Turbo Pyro goes LIVE at 12:00 Noon Eastern time today, June 19th

Turbo Pyro goes LIVE at 12:00 Noon Eastern time today, June 19th. You’ll be able to get in then.

Here’s your link for Turbo Pyro:

http://www.turbopyro.com

———————————————————————-
I DON’T KNOW WHETHER YOU HEARD THIS YET
———————————————————————-

I’ve added *more* stuff to Turbo Pyro. I want to make sure you have fun with your projects, so I added a bonus Smoke Bomb Kit and project–Making Jumbo Smoke Canisters eBook (including videos).

Be sure and get online fast and place your order. Again, there are only 400 Turbo Pyro Supplies Kits available.

Grab yours here:

http://www.turbopyro.com

P. S. You get instant access to the Turbo Pyro eBook and the Smoke-Making eBook right after you order.

P. P. S. Be sure ahead of time your credit card has enough $$ left on it to make the charge. Otherwise you may miss out. (V, MC, Amex, Disc.)

Harry

2 New Bonuses Added to Turbo Pyro

We’re getting very close to releasing Turbo Pyro this week.

Here’s some info on 2 new bonuses I have added to the Turbo Pyro Supplies Kits, as well as some tips on getting your order to go through on product launch day.

Early Bird Bonus #1-limited number: If you are one of the first 75 people who buy the Turbo Pyro Supplies Kit, you’ll get a free copy of the North American Fireworks Trade Directory, a $44 value.

The Trade Directory lists all of the important fireworks related companies on the continent. This included importers, distributors, wholesale/retail, manufacturers, consumer fireworks, special effects, display fireworks, consultants, companies who offer shooter training, attorneys, display shooters, clubs, shooter training, trade associations, fireworks transportation, fireworks insurance, publishers/booksellers, lab services, customs brokers, and suppliers of everything pyrotechnic you can imagine.

This is a book everyone in fireworks should keep on hand forever. If your order arrives without one of the Trade Directories, it is because we ran out before your order was placed. Sorry, we don’t have but 75 of these.

Bonus #2: Colored Smoke Bomb Kit, a $60 value. You get a complete kit containing smoke mix, potassium chlorate oxidizer, tubes, end caps, fuse, and a new smoke bomb project written by Ned Gorski, never published before. This project and kit give you step-by-step instructions for making up to 20 big, fat smoke canisters.

Great for daytime effects. Definitely a step up from the consumer smokes you’ve probably seen. Very easy and fast to make. The chemicals and supplies for this one will be included in your Turbo Pyro Supplies boxes. The project, “Making Jumbo Smoke Canisters,” will be available to you as a free downloadable .pdf document.

More about the Turbo Pyro Supplies Kits. Once you order your Kit, it will be shipped from Skylighter right away. We want you to have them as soon as possible before the 4th of July. The kits are shipped in two boxes. They have to be shipped that way to keep oxidizers separate from flammable items. Since both boxes contain hazardous items, they have to be shipped by US Mail Parcel Post. Occasionally, the post office will not deliver both boxes on the same day. Please be patient. The second box will arrive.

The Turbo Pyro eBook. Once you order your eBook, you will be given instructions on downloading it. It is a big file, over 10 megabytes. You will want to use the fastest Internet connection you can get. It cannot be emailed to you. The book comes in Adobe .pdf format. Sorry, no other formats, and no printed versions are available. Please read Chapter 1 immediately for more information about using the book, and playing the videos.

How to Order Turbo Pyro. If you are on our mailing list, you will receive a notice telling the exact time the link to the Ordering page will open.

When that time comes, as quickly as you can, go there and place your order. You will not see the familiar Skylighter.com shopping cart. Don’t worry. Just follow the instructions onscreen and place your order as quickly as you can. Please do not start an order and not finish it; you may lose your chance at the book and/or the Kit.

We cannot predict how many people will be trying to get through the same process at the same time. You may experience delays. Just keep trying. Have your credit card ready before you start.

Your credit card will not be charged at the time you place your order. We will charge your card on the day we actually ship, which will most likely be this Friday. You will be emailed a shipping notice and tracking number at that time. So be sure you whitelist any Skylighter.com email, to be sure and receive your shipping info. Your card will be charged the exact amount showing on your receipt. It would be a good idea to print that out and keep it.

That’s about it for now.

Harry Gilliam

Fireworking Safety, the Law, and You

I’ve covered many safety issues involved in making fireworks in my introductory essay to Kyle Kelley’s The Pyrotechnist Survival Guide, Bill Ofca’s Fireworks Safety Manual, and Dr. Takeo Shimizu’s treatise on Preventing Accident.

Much physical suffering on our part and that of our loved ones can be avoided if we heed the advice in those pages. I like to go back and review them regularly to see how well my operations are conforming to those recommendations.

But there is another very significant kind of pain and suffering we and our families may have to endure unless we pay attention to a different set of precautions as we embark on this new fireworking hobby.

I’m going to go over what it takes to make fireworks legally, and I’ll even show you how to make a magazine inexpensively to use for legal storage of the fireworks you make.

The US Department of Justice, Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) is charged with regulating explosives activities in the United States. Their regulations can be found in ATF Federal Explosives Law and Regulations, commonly called the Orange Book because of its orange cover.

Here is a link to a free online, PDF version of the Orange Book:

http://www.atf.gov/explarson/fedexplolaw/2007edition/index.htm

The book can be obtained from the BATFE directly, also, and from Skylighter.

Individual states either defer to Federal explosives regulations or develop their own explosives laws.

Local governments such as counties, cities, and townships can adopt their own sets of laws governing explosives and their manufacture.

You might be saying right about now, “What am I getting myself into?”

The simple answer is that you’ve gotten yourself into a serious hobby and art form, one which can cause personal injury and property damage, and one in which the government takes an interest, unlike knitting or stamp-collecting.

“Well, the heck with them. I don’t care about their stupid laws,” you might reply.

Well, guess what. The various governments don’t care whether you and I consider the laws stupid. They care about the laws and they care about whether or not we are complying with them. You’d better believe it.

We could sit around for hours or even days, debating this law or that one, which one is just or unjust. But that won’t change the fact of the existence of both the law and the agency, which enforces it.

The question is not whether the law is just or not, or whether or not I agree with the law.

The question becomes a simple one: “Am I willing to suffer the consequences if I am caught breaking the law and prosecuted? Is my family willing to suffer those consequences along with me? Am I willing to ask them if they are willing to suffer those consequences.”

There have been many pyros who have been caught breaking the laws concerning the manufacture and storage of fireworks. They have suffered imprisonment, high attorney fees, exorbitant fines, broken marriages, and loss of property.

In the end a law is simple. “We the people declare this activity, done this way, to be illegal. If you are caught doing it you will suffer these consequences.”

A law states just that and only that. It simply states, such and such an action is illegal, and if you are caught doing it you may suffer this punishment.

So, the choice then becomes simple. “Am I willing to comply with the law, or break it and risk those consequences?”

And, there are several different ways to answer that question.

1) Yep, I’ll comply with the law and not take the risks involved in breaking it.

2) Nope, I’ll not comply with the law. I’m going to engage in this activity in an illegal manner, and I’m willing to risk those consequences. But, I’m not gonna tell my wife I’m taking that risk with our money and property, or give her the choice of whether or not she’s willing to take that risk.

3) Nope, I’ll not comply with the law, and I’m willing to risk those consequences, and I have discussed it with my wife and family and they are willing to back me up in this activity and risk those consequences, too.

But, comply or not, we need to take that action with an awareness of the consequences of our actions, and a willingness to face those consequences like “men”. (Most fireworkers are men, so I’m comfortable using that term. No disrespect to wimmen fireworkers, though.)

I said in my safety essay mentioned in the first paragraph above, “When we first get into this, we really don’t know how serious a pursuit it will become for us, do we? How much should we invest in tools and a workshop if it turns out to be only a passing curiosity? If we progress in the fireworks hobby, our investment in it and in the tools and facility used for it, progresses along with it. Our safety precautions usually end up tagging along a bit behind our activities. That is dangerous.”

Now, in that paragraph simply replace the word “safety” with the word “legal”, as in “our legal precautions usually end up tagging along a bit behind our activities.”

The danger in doing that is that we do indeed risk the sorts of “dangers” mentioned above: imprisonment, high attorney fees, exorbitant fines, broken marriages, and loss of property. As we make choices concerning our activities and whether or not they comply with those laws, it would be wise to become educated about the laws, the consequences of breaking them, and our responsibilities to ourselves and our loved ones.

Fortunately, US Federal law is pretty straightforward and simple when it comes to hobbyist fireworking.

Once again, from the ATF Orange Book:

Page 64, Paragraph 37. “When is a manufacturer’s license required?”

“Persons who manufacture explosives for their personal, non-business use are not required to have a manufacturer’s license. However, no person may ship, transport, cause to be transported, or receive explosive materials unless such person holds a license or permit.”

Page 68, Paragraph 72. “Who must comply with the storage requirements?”

“…all persons who store explosive materials must store them in conformity with the provisions of Subpart K of the regulations…”

Pages 47-53, Subpart K – Storage

This section details storage which is in conformity with the regulations and which will satisfy the BATFE’s requirements.

Because no license is required by the BATFE, this storage might never be known about by them or inspected by them. But if a person is caught storing explosives without such compliant storage, the BATFE then has the right to prosecute that person. And, typically, they do.

These are the cases you hear about in the news if the Feds are prosecuting somebody: they were storing explosives illegally, or they caught the person transporting explosives without a license or permit.

This is another important point. While a person can make explosives for their own personal use, provided that they store them in a compliant manner, they may not transport them legally unless they have an ATF license or permit. And, that’s even across town to the test-shooting site. When traveling to PGI (Pyrotechnics Guild International) or local-club events, often transportation-coverage for members is supplied through the club license and/or permit.

But, man, if you decide to transport your homemade fireworks without a license or permit, and you get stopped and searched for whatever reason, or if you have an accident and the explosives are involved in some destruction, God Help You, because the law won’t.

By the way, the US DOT (Department of Transportation) only regulates “in-commerce” transportation, and does not concern itself with the above mentioned regulations concerning the BATFE’s requirements to only transport explosives under a license or permit. At least, that’s the philosophy they appear to have been operating under so far.

Note: It’s useful to mention that all of this is my best understanding of the current situation under the law. Things can change, and the laws are always up for re-evaluation. I am not a lawyer, just a hobbyist trying to be as informed as possible about the multitude of laws surrounding us, and the numerous “alphabet soup” agencies charged with enforcing those laws. If in doubt, consult an attorney. But remember that unless they are fireworks or explosives specialists, often they can only offer their “best opinion” for you. Quite often the law is simply not all that clear, and is left to the individual “authority on site” to render a personal interpretation of it.

It is impossible for me to even try to address the myriad of local and state laws governing the manufacture of fireworks. Suffice it to say that the same sort of reasoning and responsibilities mentioned above with regard to federal laws, also pertain to state and local laws.

If you don’t research those laws and make informed choices regarding them, you might run afoul of a state or local Fire Marshal who simply does not have a sense of humor about all of this “hobbyist fireworking.”

So, if the Feds do not require us to obtain a license to make explosives for our personal use, as long as the restrictions on storage and transportation mentioned above are complied with, “Why Get One?”

Well, that’s an interesting subject.

We’ve mentioned the BATFE, DOT, State and Local agencies, and now another of those “acronym named” agencies comes into play. The CPSC.

The Consumer Products Safety Commission seems hell-bent on putting hobbyist fireworking and pyrotechnics supply houses out of business. Despite the BATFE’s declaration that no license is required for such activities, the CPSC has repeatedly forced pyro chemical suppliers to not sell more than very limited quantities of certain chemicals and supplies to unlicensed individuals.

On top of that, even though there is a perfectly valid and available “Type 50 – Manufacturer of Fireworks” license available from the BATFE, the CPSC has told the pyro supply houses that only a “Type 20 – Manufacturer of High Explosives” license is acceptable for purchases of certain items.

Go figure. I personally don’t mind trying to get informed about the law and trying to abide by it, but man, sometimes “they” sure don’t make it easy.

So, many pyro-enthusiasts are biting-the-bullet and getting their BATFE Type 20 licenses. A background check is required, and the resulting “Letter of Clearance” must be obtained. Compliant storage, as mentioned above and described in the following section, and a simple approved work-site, such as a picnic table, are necessary.

A form must be filled out and a relatively small fee must be paid. There’s an interview, fingerprinting, and a security check. And that’s about it. You don’t have to “qualify,” be tested, nor have any particular skills or background. The BATFE is not our enemy, and if we are willing to work with them, they definitely don’t view us as their enemy.

The license covers us for materials purchases, for transportation issues, and for general peace-of-mind. I personally consider it to be a good investment, if local and state laws will allow a license to be obtained.

As mentioned already, Subpart K – Storage, in the Orange book details the BATFE’s requirements for storage, regardless of whether we have a license.

Requirements for regular inspection, by the owner, of magazines to ensure that they have not been tampered with, are detailed. Housekeeping, smoking, repair, lighting, and various other issues are also addressed in this section.

Note: Interestingly, the requirements for keeping “Records and Reports” which are detailed on page 37, pertain only to “licensees and permittees.” The questions and answers regarding the requirements for “Recordkeeping,” back on page 67-68, address only licensees and permittees, as well. So while there may not be specific requirements for recordkeeping concerning the stored explosives for a non-licensed hobbyist, it’s probably a good idea to keep a log of the weights of the explosives taken in or out, or at least put in, so that the maximum weight of 50 pounds is never exceeded. A regular inventory of such explosives and their weights could also easily answer any potential questions concerning the weights and types of explosives stored in the magazine.

In general, most hobbyists install some form of a Type 4 storage magazine to comply with these requirements. A Type 4 magazine is a permanent magazine in which “low explosives” (as defined on Page 48) may be stored.

Among common fireworks components and devices, the only things, which cannot be stored legally in a Type 4 magazine, are loose “flash powders” and “bulk salutes.” Bulk salutes are flash devices stored all in one container or box together. If salutes are going to be stored in a Type 4 magazine, they must be mixed in a box with some color shells or similar. Loose flash powder may not be stored in a Type 4, period.

Other than that, a Type 4 is the storage most of us need, even if we are getting a Type 20 license (Manufacturer of High Explosives). In order to comply with CPSC’s requirements, if we explain to ATF why we want that license, and declare that we will not store loose flash powder or bulk-salutes in our Type 4 magazine), then typically the inspectors will tell us that we’re good-to-go with a Type 4.

Just remember, any explosives we manufacture and store must be stored in such a compliant magazine, whether or not we get a license.

Page 51 of the Orange book details the various requirements for the construction of Outdoor and Indoor Type 4 magazines.

Much less expensive than magazines made for just that purpose, metal shipping containers are commonly used to make outdoor Type 4 magazines They can be relatively inexpensively modified to meet the BATFE’s requirements. Page 54 has a table of distances to determine how far an outdoor magazine must be situated from inhabited buildings, highways, railways, and other magazines.

Remember the ATF places limits on the total, maximum weight of explosive material that may be stored in each type of magazine. If one wishes to install/construct an outdoor Type 4 magazine in their area, it’s useful to consult with others in your area who have done so, and with the BATFE to see what their specific recommendations and requirements are.

Many hobbyists install “Indoor” Type 4 magazines to have BATFE compliant storage for their activities. The requirements for these magazines are spelled out on Page 51.

Indoor Type 4 magazines may store a maximum of 50 pounds of actual explosive materials (does not include the weight of the containers, etc.) The magazine must be “fire-resistant and theft resistant.” “No indoor magazine is to be located in a residence or dwelling.”

An indoor magazine must be in a separate structure—not in a residence or dwelling. It appears that there is no minimum distance it must be separated from the residence of the hobbyist. The separate structure may be a garage or shed near a residence, but it may not be attached to it.

“Indoor magazines are to be constructed of masonry, metal-covered wood, fabricated metal, or a combination of these materials. The walls and floors are to be constructed of, or covered with, a non-sparking material. The doors must be metal or solid wood covered with metal.”

Covering any exposed metal to make it non-sparking can be as simple as painting it with a high-quality paint/coating such as epoxy-appliance-paint or rubberized truck-bed-lining/coating.

“Hinges and hasps are to be attached to doors by welding, riveting, or bolting (nuts on inside of door). Hinges and hasps must be installed so that they cannot be removed when the doors are closed and locked.”

“Locks. Each door is to be equipped with (i) two mortise locks; (ii) two padlocks fastened in separate hasps and staples; (iii) a combination of a mortise lock and padlock: (iv) a mortise lock that requires two keys to open; or (v) a three-point lock.”

From Wikipedia: A mortise lock is one that requires a pocket–the mortise–to be cut into the door or piece of furniture into which the lock is to be fitted. In most parts of the world, mortise locks are generally found on older buildings constructed before the advent of bored cylindrical locks, but they have recently become more common in commercial and up market residential construction in the United States.

“Padlocks must have at least five tumblers and a case-hardened shackle of at least 3/8-inch diameter. Padlocks must be protected with not less than 1/4-inch steel hoods constructed so as to prevent sawing or lever action on the locks, hasps, and staples.”

“Indoor magazines located in secure rooms that are locked as provided in this subparagraph may have each door locked with one steel padlock (which need not be protected by a steel hood) having at least five fumblers and a case-hardened shackle of at lease 3/8-inch diameter, if the door hinges and lock hasps are securely fastened to the magazine.”

So, if I have my indoor magazine in a shed, garage, or other building, which has a door, which locks with two mortise locks, the requirements for the lock on my magazine get drastically simplified.

“What the Hell??!!” I can just hear you saying right about now.

“How can I ever comply with all of this, only half of which I sorta understand?”

Well, it turns out it can be pretty simple, really.

An extremely simple indoor Type 4 magazine, which will satisfy these requirements, is a good-quality gun-safe, available at gun shops and sporting-goods stores. Make sure the locks meet the above requirements, and that the building is separated from your residence. Use epoxy appliance spray paint to cover any exposed metal on the inside of the magazine. Install some nice shelving in it. Drill some holes in the bottom and/or back of it to bolt it to the wall and/or floor to make it “theft-resistant.” And, there you have it, presto-chango, BATFE-compliant, Type 4, indoor storage.

Another option, which will come up if you search online for “lockable powder storage container,” is BATFE-compliant black powder storage boxes from sporting-goods outlets such as Cabela’s.

Here’s how you can convert a Ridgid Jobsite Storage Box, from Home Depot, into a legal Type 4 Indoor Storage magazine.

This is just one approach to creating an Indoor Type 4 magazine, compliant with the BATFE’s requirement that “all persons who store explosive materials must store them in conformity with the provisions of Subpart K of the regulations” contained in the Orange Book. (Page 68, Question 72)

Note: Please keep in mind that what follows is my interpretation of the specifications and regulations in the orange book, combined with the advice I have gotten from others. I’m no lawyer or ATF inspector. These regulations are always up to personal interpretation by the individual ATF inspectors in your area. If you have any questions about the below-listed points, it is best to clarify them with your local ATF office.

Let’s review the BATFE’s specifications for “compliant” storage.

Type 4, Indoor magazine:

• Is for storing “Low Explosives.” (no loose flash powder, no bulk salutes, no dynamite) (555.202 (b))
• May not be located in a residence or dwelling. (555.210 (b) Indoor (1))
• May only be used to store up to 50 pounds of explosives. (ditto)
• Need not be any “minimum distance” from residences or road. (555.206 only pertains to “Outdoor Magazines”
• Is to be fire-resistant and theft resistant. Need not be weather-resistant if the building in which it is stored provides protection from the weather. (555.210 (b) Indoor (1))
• Must be constructed of masonry, metal-covered wood, fabricated metal, or a combination of these materials. The walls and floor are to be constructed of, or covered with, a non-sparking material. The door/s must be metal or solid wood covered with metal. (555.210 (b) Indoor (2))
• Hinges and hasps are to be attached to doors by welding, riveting, or bolting (nuts on inside of door). Hinges and hasps must be installed so that they cannot be removed when the doors are closed and locked. (555.210 (b) Indoor (3))
• Each door is to be equipped with (i) two mortise locks; (ii) two padlocks fastened in separate hasps and staples; (iii) a combination of a mortise lock and padlock; (iv) a mortise lock that requires two keys to open; or (v) a three-point lock. (555.210 (b) Indoor (4))
• Padlocks must have at least five tumblers and casehardened shackle of at least 3/8-inch diameter. Padlocks must be protected with not less than 1/4-inch steel hoods constructed so as to prevent sawing or lever action on the locks, hasps, and staples. (ditto)
• Indoor magazines located in secure rooms that are locked as provided in the above specifications may have each door locked with one steel padlock (which need not be protected by a steel hood) (same lock specs as above) if the door hinges and lock hasp are securely fastened to the magazine. (ditto)
• There is to be no smoking, matches, open flames, or spark-producing devices within any room containing an indoor magazine. (555.212)
• The workspace used to manufacture fireworks must be at least 200 feet away from the magazine. Many hobbyist fireworkers maintain a pyro-shed, or a “work area” as simple as a portable table and tent-shelter, separated from the residence and storage magazine by a minimum of 200 feet.

I have a nice shed on my property. It is weatherproof. It is separated from my residence. I can create a “back room” in it, in which there are no spark-producing devices such as light switches, machines, or electrical outlets.

I can install two locks (a keyed entry lock and a deadbolt lock) on each of the doors leading back to the back room: the main entry door and the door to that room.

I can use the “front room” of the shed as a non-pyro workshop, as long as I keep the back room and magazine closed and secured during such operations.

So, given all of the above BATFE requirements and specifications, what sort of Type 4 indoor magazine could I put in the back room of my shed?

My pyro-buddy, Gary Smith recently sent me a picture of such a magazine design that he’s been working on. It got my “wheels turning.”

This is simply a Ridgid Jobsite Storage Box, typically used on construction sites for overnight storage of valuable tools and materials. I bought one of these boxes at my local Home Depot.

This box is constructed per the BATFE’s specifications, is coated completely with heavy orange paint, making it non-sparking, and is fire-resistant and theft-resistant, especially when it is bolted to the floor or wall.

It has two recessed areas for the kind of theft/tamper-resistant locking the BATFE specifies.

For the locks, Home Depot sells Master Lock Magnum locks, Model M5XT. They have 3/8″ thick shackles, measured across the “points” of the octagonal cross-section. The shackles are “boron-carbide,” and the locks are specified as having stainless-steel rust protection. The package indicates “Meets Maximum ASTM Industry Strength Standards,” and one package comes with two locks, which open with the same key.

The locks are specified on the package as having 1-inch of clearance between the shackle and the body of the lock when the locks are locked. The Ridgid job box instructions specify a Master No 5 lock, which has between 7/8 and 1 inch of such clearance.

So, it looks like these locks meet both the BATFE and Ridgid specifications. I’ll keep the lock-package inside the magazine in case a BATFE field inspector ever wants to go over the lock specifications to verify that they do indeed meet his/her interpretation of the agency’s requirements.

The locks are installed in the job box and held in place with u-bolts and nuts, which come with the box. When the door is closed, and the locks are locked, the body of the locks close around L-shaped bars, which project from the door. When the lock is unlocked, the lock-body slides out further in its little compartment and creates enough space for the L-Bar to slide into. (Trust me, it works just fine.)

When the door is closed and locked, the method of protecting the locks from tampering is as specified by the BATFE, including that the box is to be contained in a securely locked building.

Note: I whacked my projecting bars with a mini-sledge hammer to adjust them, so that the maximum length of the L part of the bars is engaged by the locks when they are locked.

I used a hand-held grinder, crowbar, sledgehammer, and wood block to remove the feet from the “bottom” of the box, which is now to be the “back” of the unit when it is installed as a magazine. Grinding the welds to cut them, and prying/pounding on them eventually got them off of the box.

Note: I have heard of serious incidents and accidents where someone using a grinding wheel or other grinder to sharpen tools or grind something else, has set off pyrotechnic compounds or fireworks which were stored nearby. Simply put, Do Not Grind Any Metal Near Pyrotechnics or Fireworks. Please!

I then figured out which way I wanted the door to open in the new box configuration. That then determined which end of the box would be the new “bottom” of it.

I used construction adhesive to reattach the feet to the new bottom, and to glue the swinging handle to the box, so that it would stay out of the way during installation. Placing the feet on the new bottom of the box, will keep the box up far enough off the floor to allow the door to swing freely without hitting the floor while opening and closing.

I allowed the glue to set up and dry completely before going on to the next steps.

I wanted some nice, wood shelves in the magazine, strong enough and far enough apart to support 5-gallon buckets of composition if needed.

I used some 3/4-inch-thick plywood, and some 1-inch X 1.5-inch wood scraps to create this shelving. All the wood is simply held in place with good-quality construction adhesive.

I ran a good bead of glue under the back edge of the shelves where they meet the back of the box to support them and prevent them from bowing under weight. Finally, I installed some wire-mesh “spice racks,” from the shelving department of Home Depot, on the inside of the door to provide some convenient storage for small items like one-pound cans of Goex black powder. These racks were installed so they fit between the wood shelves when the door is closed. The bolt-ends and nuts on the inside of the units were covered with clear caulking to make them non-sparking.

To install the magazine in the back room of the shed, I drilled four 1/2-inch holes in the back of the magazine, and used 1/2-inch lag-bolts and washers to secure the box to the plywood wall.

The heads of the bolts and washers were also covered with clear caulk to ensure they are non-sparking.

So, there you have it, one simple option for a legal magazine complying with the BATFE’s requirement for safe storage of explosives.

If an individual inspector ever disagrees with any of these design criteria, I’d be willing to explain the reasoning behind my “understandings,” and I’d be willing to be further educated on BATFE’s requirements and adjust my operation and magazine accordingly.

Happy fireworking, And stay safe and legal,

Ned

ngorski@skylighter.com

Gary Smith’s Secret to Making Roman Candles

What’s All the Mystery about Making Roman Candle Fireworks?

I really like Roman candles. But even though Roman candles appear to be the simplest of fireworks devices, they are a real challenge to make so that they perform consistently. Especially if you use the traditional methods you’ll find in all the books.

I’m going to show you a secret method for making Roman candles that you haven’t seen before. I promise you absolutely will not find Roman candles made like these in any of the books (at least, not yet!). Best of all, you can use this new method to overcome all the Roman candle problems that traditional candle-making methods create.

Look. Where rubber hits the road is how well your fire works in a fireworks display, right? Well, read on and learn how Roman candles work, what goes wrong, and how to make Roman candles like nobody you know has ever seen.

Here’s a video of one of the first successful Roman candles I made using the method I’m about to teach you.

Notice now consistent the timing is between the shots. One star is coming down and going out, quickly followed by the next shot. That kind of consistency and effect is what I was going for. And that’s what is hardest to achieve using traditional Roman candle fireworks-making techniques.

With all the candles I’ve made using this new method, the timing between shots has been within one second of each other. If you talk with pyrotechnics folks who have made their own Roman candles, they’ll tell you how remarkable that is.

You see, anyone can learn how to make a Roman candle, but making them so that the timing and height of the shots is consistent, well that’s what you don’t see very often.
Of course, Roman candle fireworks are a great way to test the color, burn time, effect and ignitability of your new star compositions. And a single candle is just fun to light, sit back, and enjoy. You can gang multiple candles together, say 7 of them in a bundle, or set them up in a fanned rack to fill the sky from left to right with Roman candles’ shots.

So Why is a Roman Candle Firework Called Roman?

Despite the fact that we Gorskis prefer to call these devices “Polish Candles,” for some reason that name has not caught on yet. So, why were these devices called “Roman candles” to begin with?

It seems that as far back as the early 1800’s, both French and Italian authors were using the term “Roman candles” to describe such devices. Since Italy was one of the countries which greatly influenced the development of fireworks, it is not very surprising that one of its most prominent fireworks devices would have its name associated with its greatest city, and the name of its once-sprawling empire.

Exactly What Is a Roman Candle?

Traditionally, a Roman candle has been thought of as a single-tube fireworks device which fires multiple, consecutive shots of projectiles skyward, and which emits a fountain-like spray of sparks between shots.

Those projectiles can be individual firework stars, comets with various colors and effects, single crossette comets, mine-shots of multiple stars, combination star-and-report devices, or small aerial star shells.

But one comet fired skyward from a mortar is sometimes considered to be a single-shot Roman candle. And indeed, single-shot candles, arranged in fan-shaped mortar racks, have become common in many modern displays.

Consumer-firework Roman candles can be as small as 1/2-inch inside-diameter tubes, and large professional-display candles can be found with a tube ID as large as 3 inches.

I’d suppose if you asked someone, “What are the most common types of fireworks you can think of,” the response would be something like, “Firecrackers, sparklers, bottle-rockets, and Roman candles.”

Certainly Roman candles play a part in many of our childhood fireworks memories. Often they were held in our hands as they fired, but there have been so many mishaps resulting from malfunctioning candles that hand-held Roman candles are now discouraged.

I once made the mistake of thinking I could hold a one-inch display candle in my hand as it fired. The first shot propelled a star skyward, and the rest of the candle backward out of my hand to who-knew-where. I had to quickly find it and stabilize it with my foot as it finished firing. I still haven’t lived that down in my local fireworks guild. I don’t recommend you try any similar stunts.

With these larger Roman candles, it’s best to tape them to a stake and firmly secure them to the ground before ignition.

How Is a Roman Candle Constructed?

The most common, and traditional method of Roman-candle construction involves alternating layers of black-powder lift charge, cylindrical stars, and a slow-burning candle/delay composition, with the bottom of the tube plugged with a clay bulkhead.

If you imagine lighting the candle’s fuse, it will burn down until it ignites the first increment of the delay composition. That rammed increment burns slowly like a gerb (fountain), spraying sparks out of the end of the tube, which would normally be pointing skyward. Of course, when I say “normally be pointing skyward,” this “dog and Roman candle” video from YouTube pops into my mind: http://www.youtube.com/watch?v=i8mDAae7LEY. That one shot just about takes out the kid and the old man at the same time!

When the last part of that first increment of delay composition burns through to the first star, the prime on the star burns quickly and ignites its whole surface. That, in turn, lights the first layer of black-powder lift charge, which propels the star out of the tube. At the same time, the top of the second increment of candle composition is ignited, which begins a repeat of the whole process.

The Roman candle in the sketch is called a “four-ball” Roman candle, since it will sequentially shoot four stars out of the tube. “Ball” refers to the ascending ball of flame each star will produce.

Typically candles are made with pumped, cylindrical stars, which have flat bottoms and tops. The flat bottom holds the black-powder lift charge in place, and the flat top supports the delay composition nicely.

Why Do I Make Roman Candles?

In the past 20 years or so in this hobby, I’ve only tried to make Roman candles a few times, although they are among the most elementary of devices. Quite honestly, in those attempts I was never completely satisfied with the results.

And you know what’s funny? Even though I’d made 16-inch aerial fireworks shells and 36-inch diameter girandolas, I felt like I couldn’t make a consistently performing Roman candle that would live up to my expectations.

One reason I wanted to get good at producing nice little Roman candles is that they can be fired in any location suitable for the discharge of consumer fireworks. Big fireworks devices like big shells and girandolas require a big display site and a display permit. But it’s nice now and then to make a little rocket or Roman candle and be able to take it outside to shoot and see how it performs.

In his 1947 book “Pyrotechnics,” George Weingart has a section on rolling cases (tubes), for Roman candles. He also has instructions for making an individual, 3/8-inch ID, eight-ball Roman candle.

Weingart describes a simple machine for mass-producing consumer-fireworks candles. I have seen the remains of a similar machine at the Rozzi’s Famous Fireworks plant near Cincinnati, Ohio. My understanding is that the machine I saw was the very one Weingart based his sketches and descriptions on.

How to Make a Roman Candle

I’ve seen traditional Roman-candle-making instructions elsewhere, and they seldom differ significantly from the ones in Weingart.

A parallel tube is plugged at the bottom with a rammed increment of clay or with a glued-in section of wooden dowel. A scoop of black-powder lift charge is loosely put into the tube, followed by a star, which fits nicely into the tube. This is capped off with an increment of the candle-composition delay powder, which is rammed “with about six light blows of a small mallet” according to Weingart.

And this is where Roman-candle construction gets tricky. That increment of delay composition must be rammed solidly enough to get it really consolidated and locked into the tube. That is necessary in order to prevent fire from being prematurely blown down the tube past it when the star above that increment is shot out of the tube.

The delay charge must also be in the tube tightly enough that fire cannot creep between it and the inner tube wall as it burns, which would also prematurely ignite the star below it.

If you’ve ever rammed fountain composition in a paper tube, you know it takes a fair amount of force to solidly compact the powder, in order to produce the right effect when the fountain is lit.

But, when one is ramming Roman-candle delay composition, that increment sits on top of a loose star sitting on loosely granulated black-powder lift charge. This is an inherent conflict: not an ideal situation for getting a solidly compacted increment of delay composition.

And here’s what you see as a result–the most commonly seen Roman-candle failures–stars which fire from the tube in a rapid-fire, unevenly-paced manner; sometimes more than one star fires at once; or the paper tube ruptures because of the amount of pyrotechnic material, which ignites everything at once prematurely.

All of this results from not having a solid base on which to ram each increment of candle composition. That makes the construction of these simple devices a real challenge, especially in candles larger than about a half-inch ID. Larger diameter delay increments are harder to solidly compact sufficiently than smaller diameter ones.

There must be a better way.

Enter my pyro buddy, Gary Smith. Recently on Passfire.com Gary posted a video of a fairly complex Roman candle he’d made. The individual shots were color-to-report inserts, which are harder to make than simple stars.

But, what I noticed immediately was that his shots were very evenly spaced apart, and that there was a nice fountain of fire-dust spewing from the mouth of the tube between shots.

This was a very nicely constructed, consistently-performing Roman candle, that I knew from personal experience was hard to achieve. I simply had to know more.
Gary was kind enough to share with you and me the unique method he developed of achieving nicely compacted, traditional delay increments between the shots. And that is what produced the consistent effects, which so impressed me when I first saw his video.

Using Multiple Tubes to Make One Roman Candle

Huh? Say what?

I thought we’d already defined a Roman candle as a “single-tube fireworks device which fires multiple, consecutive shots of projectiles skyward.”

How can we use more than one tube to make a Roman candle?

Well, therein lies Gary’s trick, which hopefully will forever be known as the “Smith Method” of constructing candles.

Looking at the sketch of the Roman candle above once again, you’ll notice there is a recessed, empty space below the clay bulkhead in the paper tube. Putting the tube on a base, which has a ramming nipple, and then dropping loose clay into the tube and ramming it with a drift and mallet creates that void.

Way back in Skylighter Newsletter #89, I gave directions for mixing clay nozzle and bulkhead mixes. I also showed how to ram nozzles and bulkheads, and a photograph of a cutaway tube with a nozzle rammed in it.

Either of those clay mixes is usable for the clay plug at the bottom of a Roman candle. And the photo shows how a clay nozzle or bulkhead locks into a paper tube by slightly expanding the tube in that area.

I can just imagine Gary thinking, “How can I get each delay increment solidly locked into the paper tube the same way the clay plug is?”

And then the light went on in his head: “Cut the tube into sections, ram each delay increment solidly into its section, and then reassemble the tube sections into one solid case.”

I imagine a picture popping into his mind something like the sketch below.

Although the sketch shows a 4-ball candle, additional 2-inch middle sections can be added or removed to increase or decrease the number of shots.

Note: The top, 3-inch or longer tube section creates the first “mortar” out of which the first star is shot. Within certain limits, the length of a mortar determines how high the projectile goes. Technically, 3 inches is the shortest practical tube from which to shoot the first star. But with a tube that short, the first shot will not go as high as the shots that follow it. So, I actually prefer to use a top tube section that’s 5-inches long.

I have arrived at the specific dimensions for this particular Roman candle based on my particular stars and delay composition. To the left of each increment of the delay (candle) comp there is a 1/2-inch void just like the one to the left of the clay plug.

The nipple on the ramming base creates this 1/2-inch recess in each section. A tube section is slipped onto the ramming base. The proper amount of delay composition is loaded into the tube and then rammed with a drift and mallet.

This creates a very solid, securely positioned increment of delay composition, which prevents most types of Roman candle failures.

There it is, simple as that: the Smith secret to Roman candle construction.

Now, here’s how to make a Roman candle using this method to show all the steps involved.

Now, How to Make a Roman Candle

For this Roman candle, I’m going to alternate shots of D1 glitter stars with shots of Willow Diadem silver-streamer stars. First a glitter shot, then a silver streamer, then glitter, silver streamer, etc. The candle in the video at the beginning had only silver-streamer stars.

For the willow diadem stars, I’m still using the total amount of metal that is specified in the formula. But rather than using three different types of metal, I’m only using fine, spherical titanium, Skylighter #CH3010. This long-burning star leaves a nice, long silver tail behind it that “pops” as the bits of titanium catch fire and burn.

The dimensions in the sketch above are based on my primed 5/8-inch diameter, 5/8-inch long pumped stars, which I made the same way I made the gold-glitter comets in Fireworks Tips #111.

I prime the ends and sides of the stars so that fire is transferred as quickly as possible from the top to the bottom of the star. The final primed stars end up being a little under 3/4-inch diameter and about 3/4-inch long.

The star dimensions dictate that I use 3/4-inch ID parallel tubes for this project. Either the extra-strong, 1/8-inch wall Skylighter TU1066 tubes, or the standard, 1/4-inch wall Skylighter TU1065 tubes will work well in this project.

These long tubes work well because they can be marked, and all the Roman candle sections can be cut out of one length of tube. This makes it easy to reassemble the sections later on.

I want to make an 8-shot candle, so I mark and cut a tube as shown below. I write a number on each section, starting with #1 at the bottom of the tube.

The markings will enable me to reassemble the tube sections exactly as they came apart, which will increase the potential for me to arrive at a nice straight finished candle. I allow about 1/16-inch for each of the saw cuts.

In the drawing above, notice that there will be a star at each of the cuts. So I mark 8 cuts, plus the cut at the top of the candle. The bottom section will be 1.5-inches long and the top one will be 3-inches long.

Then I cut the tube into sections.

I use a little sandpaper to smooth the inside and outside edges of each end of the tube sections. Smooth ends make for smooth reassembly later on.

Now I put section #1 on the nipple of the ramming block with the bottom of the tube down.

I made the ramming base and nipple by drilling halfway through a piece of 3/4-inch thick plywood, and epoxying a length of 3/4-inch diameter aluminum rod into the hole. I got the rod from Home Depot (in the nuts-and-bolts aisle where they have a rack of metal rods and angles), and cut it with a hack saw just long enough that 1/2-inch of it projects from the plywood. I used a file to smooth the top end and edges.

I load 10 grams (one flat 1/2-tablespoon) of bulkhead-clay mix through a funnel into the tube. When loading the clay into the short tube through the funnel, I use a 1/2-inch wooden dowel to push the clay through the funnel and slightly compact it into the tube. This helps get all the clay through the funnel and down into the short tube, so it doesn’t spill out over the top.

I ram the clay plug with a 3/4-inch rammer from one of my sets of rocket tooling, and 8 moderate blows with the rawhide mallet. This results in a 1/2-inch thick plug in the tube section. A section of 3/4-inch wooden dowel could certainly be used as a rammer in this project, as shown in the article on making gerbs.

Note: I want to fully consolidate the clay and lock it into the tube without damaging or splitting the tube. This takes a bit of practice. With the softer, standard tubes, a slight bulge will form in the tube, which can be felt if one runs their fingers up and down the tube.

Now it’s time to ram the delay-composition increments into the other sections of the tube. I have played with a variety of delay compositions, from relatively fast-burning ones to those that are slower burning. I like to keep the delay increments about 1-inch long between the stars. This provides a nice, solid plug, which does not allow fire to pass prematurely around it.

So, the burning speed of those 1-inch increments determines how much time there is between shots of the Roman candle. With the stars I am using, I prefer the timing I get using the following candle delay composition (This is a classic star formula which can be found in various books).

Chrysanthemum 8 (from Shimizu) Delay Composition

Chemical	%	79-gram batch
Potassium nitrate	0.49	35 grams
Charcoal (airfloat)	0.40	29 grams
Sulfur	0.06	4 grams
Dextrin	0.05	4 grams
Water	+0.10	7 grams
Total	1.10	79 grams

Note: The weights have been rounded off, and this size batch will make enough composition for the 8-shot Roman candle I’m making.

I grind the potassium nitrate in a blade-type coffee mill fine enough to pass a 100-mesh screen. I do the same with the sulfur. The charcoal and dextrin are already that fine.

25-50% of the airfloat charcoal can be replaced with 80-mesh or even coarser charcoal for longer hanging sparks in the fountain plume between candle shots.

The chemicals are put in a sealed plastic tub and shaken to mix them. Then they are worked through a 20-mesh screen or kitchen colander 3 times to thoroughly mix them and break up any remaining clumps of chemical.

Using a spray bottle, I spritz the composition with water as it sits in a plastic tub on a scale, until 7 grams of water has been added. Between every couple of spritzes, I swirl the comp in the tub to spread the water around.

I work the water into the powder with gloved hands and then push the damp composition through the 20-mesh colander twice to really integrate the water.

Then, just as I did with the increment of the clay in tube section #1, I ram increments of the still-damp delay composition into the remaining tube sections. I always place each section with its bottom down on the ramming nipple. This creates that 1/2-inch void in the bottom of each section as shown in the sketch.

Sections #2 through #8 now get 10 grams of the composition rammed into them. Ramming that amount of comp yields delay increments that are 1-inch long in each section. Finally, I ram 5 grams of the composition in tube section #9, which produces a 1/2-inch long delay increment.

Then I allow the delay increments to dry overnight, using my drying box. They would dry in a few days if they were put in a warm location of the storage area.

Note: Often, directions for making candles specify ramming dry, granulated delay composition. At first I wondered if I should granulate and dry the comp, and I discussed this with Gary. His theory is that damp composition slightly wets the adhesive layer inside a paper tube, and when it dries it really glues the delay increment in place. Makes sense to me, and ramming it damp really creates a dense, hard plug of composition.

Once the tube sections and delay increments are dry, it’s time to assemble the sections of the Roman candle, with lift charges and stars installed as I go along.

One homemade jig really helps at this stage, and ensures the assembled Roman candle ends up perfectly straight. I took this tip from one of the photos of Gary’s process, and expanded upon it for my own purposes.

The jig is made up of two, 36-inch long pieces of 1-inch by 1-inch aluminum angle channel from the same section of Home Depot mentioned above. One of the pieces has two 1/4-inch diameter, 2-inch long carriage bolts and nuts installed in each end to act as feet to stabilize the channel during use.

I lay out the now-dry candle tube sections in numerical order on the jig. I also lay out my stars in the order in which I want them fired, along with a cup of FFg sporting-grade black powder from a gun shop.

Of course, with a bit of dialing in, I could also use my homemade black powde for the lift.

I’ll be using Elmer’s glue to assemble the candle and a 1/4-teaspoon kitchen scoop to measure the black powder lift charges.

I have cut out little disks of tissue paper the same diameter as the tube OD to go between the stars and the lift powder. The tissue prevents the black powder from migrating up past the star between the star and the inner wall of the tube. I want to keep all the lift powder down below the star to maximize the star’s propulsion out of the tube.

To assemble section #1, I stand it, bottom down, on my workbench, and drop 1/4-teaspoonful of the black powder into the top of that section through a little funnel. I place a tissue paper disk over the top of the tube and push a star and the tissue down into the tube, seating it firmly against the black powder. Then I apply a thin ring of Elmer’s glue around the top edge of that section.

I then push section #2, bottom down, onto the glued section #1, and wipe any excess glue off with a paper towel. Then, while I’m pressing those sections together, I pick them up and lay them into the trough of the alignment jig. Pushing them down on the jig ensures that they are perfectly aligned, and I push them together end-to-end to make sure the glue joint holds tight.

Then I carefully pick them up, continuing to press the sections together, and stand the assembly upright.

Again I load lift powder, tissue, and star, and run a ring of glue around the top of the tube. Then, I assemble section #3 in the same manner as #2.

I repeat this process until all nine sections have been assembled and I have the whole shebang resting in the jig.

I could just press the sections together end-to-end, make sure they’re sitting nice and straight on the jig, and let the glue dry. But, nooo, not me. I’m a bit more of a perfectionist than that.

Note: That’s kind of a funny revelation. When I was a kid, my Dad was always hollerin’ at me for not cleaning up his shop after using his tools, or for not finishing up a project I’d started. Now, with my pyro avocation, I’ve gotten very particular about cleanliness in my shop in order to prevent serious accidents. And I’ve also come to know that meticulous work habits are a sure way to achieve consistency with my artistic fireworks devices. We live and learn. Sorry, Dad, and thanks; I finally got it!

So, I go one more step to really clamp the candle sections tightly, end-to-end as the glue dries, and to ensure my candle ends up perfectly straight when it’s dry.

I lay another piece of the aluminum angle channel on top of the glued-up candle. (You were wondering what that extra piece was for in the pictures above, right?)

Then I take 12-inch pieces of masking tape and put bands of the tape, stretched tightly with the sticky-side-out, around the aluminum and candle sandwich. This really holds the glued tube sections nice and straight.

To really pull the tube sections tightly together as the glue dries, I install two 1/2-inch square, 4-inch long, pieces of steel bar, and two tightened strap clamps. Gently tightening the clamps snugs the tube sections together, but I don’t tighten them so much that the ends of the tubes are damaged.

Of course, long rubber bands or elastic bungee cords could be used in place of the strap clamps. Pieces of wood could also be used instead of the steel crossbars.

It takes 2-3 hours for the glue to dry sufficiently to allow the assembled candle to be removed from the jig. I remove the strap clamps and steel bars, tear the bands of masking tape, which remove easily because they were applied, sticky-side-out. Et voilà! A sturdy, straight Roman candle emerges.

A little 100-grit sandpaper quickly knocks any rough spots off the outside of the tube joints.

Well, let’s stick a piece of Visco fuse into this puppy, take ‘er outside, and fire it up. Right?

Hold on there, podnah. Not so quick. The candle tube, as it currently is, really is not that strong yet. End-to-end glue joints don’t have much structural integrity. If this particular Roman candle is going to survive the pressures when it fires, those joints will have to be reinforced a teensy bit.

Enter fiber-reinforced, gummed, kraft-paper tape. One of my favorite supplies is a tape that I get from Staples: 2.8-inch wide, fiberglass reinforced, paper packaging tape, Staples #468231. This stuff is light, thin, and really molds well to the tube once it’s wet.

Although I usually cut the tape to length with scissors because of the fiber-reinforcement, I use my manual tape dispenser as a wetting station to wet the tape. A sponge could also serve this purpose.

The glued-together candle is 18.5-inches long. I cut four 18-inch strips of the kraft tape to use to reinforce the tube. Each strip will run lengthwise on the tube, and will wrap around to cover about 3/4 of the tube circumference. Therefore, the four strips, staggered as they are applied, will create 3 complete layers of tape on the candle.

I run a strip of tape through the dispenser’s wetting station, and carefully apply it lengthwise on the Roman candle tube. Each strip has to be kept straight; the long edge of the tape needs to be parallel to the length of the tube. I get the first strip pasted down tight. Then, I butt the long edge of a new strip right up against the edge of the first piece of tape. Since each strip only wraps around 3/4 of the tube’s circumference, once it is pasted down, the second piece of tape will overlap the first one some. I repeat this process for all 4 pieces of tape. That way the gaps in the tape get staggered around the circumference of the tube.

In between each strip application, I burnish the previous strip down nice and smooth with a scrap of paper tube. When all the strips are on, I give the whole tube a nice hard burnishing to produce a flat, smooth application of all the tape.

Oh, yeah, that baby’s looking nice, and feeling strong now. After inserting a hooked piece of Visco fuse as shown in the candle cross-section sketch, I put on a wrapping of colorful paper, and tie the paper snug around the fuse. Now she’s ready to take out, tape to a stake in the ground, and light.

You might be thinking, “That was a lot of work to produce one, simple fireworks device, wasn’t it?”

Naah. Not really. There was probably about an hour’s worth of work in the construction of that one candle, all told. It may sound like a lot of time and effort, but once you get going on the project, it’s really not that complicated.

This new Smith Method of making Roman candles is such an improvement and can produce such nice consistent results for the hobbyist, that I just can’t help but be excited about it, especially after my past, less satisfying results.

When I carefully look at the videos of all the Roman candles I made using this new method, every initial delay after ignition was just about exactly 4 seconds, and every intermediate delay was within one second of 8-seconds long. It don’t get no better than that.

On top of that, I’m already imagining creative variations on the above theme: mine-shot candles, crossette-comet candles, color-to-report-insert candles, married-comet ones, matrix-comet projectiles, and crackling-microstar-comet varieties.

I hope to tackle those projects in the coming months.

Additionally, the Roman-candle competition at the PGI (Pyrotechnics Guild International) convention allows candles up to 2-inches ID. I do have some nice, stout 1.5-inch ID tubes, so I just may have to come up with some larger versions of these babies to take to Mason City, Iowa in August.

Have fun and Stay Green,
Ned
ngorski@skylighter.com

How to Make a Fireworks Strobe Rocket

What is a Strobe Rocket?

If I had to make the choice of being able to construct only one type of rocket, it would be a difficult decision. I truly love the low-level simplicity and effect of the Spectacular Glitter-Tailed Rocket with Willow-Diadem-Horsetail Finish.

But for pure, high-powered, awe-inspiring and crowd-pleasing rocketry display, the strobe rocket is sure hard to beat.

The following video is a six-pound strobe rocket. I constructed this 1.5-inch ID model in a seminar I taught at a local pyro club event.

Note: The “one-pound” and “six-pound” rocket motor designations have nothing to do with what the rocket actually weighs. They are fireworking terms, which refer to the rocket engine tube’s inside diameter (ID), and have their roots in antique rocket-making terminology.

That baby was really up there by the end of its flight. You can tell that from the delay between the video and audio of the report heading. These large strobe rocket engines really do sound like helicopters in flight, too. For such a relatively simple fireworks device, they sure are satisfying and attention grabbing when they work well.

Even when they don’t “work well,” and CATO (blow up) on the launch pad, these rockets are impressive! There is a lot of power packed into that engine tube, so it pays to put a long piece of Visco fuse on them, and have everyone plenty far away from the launch area just in case.

This is the third in a series of whistle-related articles. The first installment dealt with making whistle fuel and simple fireworks whistles. That same fuel will be used in these strobe rockets. The second article described the construction of basic whistle rockets. Many of those same techniques will be used now to make strobe rockets. So, it’s a good idea for you to familiarize yourself with those basic methods before forging ahead with this project.

Note: I will not be repeating all the basic construction details from the whistle rocket tutorial. You really will need to be familiar with those techniques if you are going to tackle this strobe rocket project.

A strobe rocket utilizes whistle fuel for power, along with strobe fuel to create the popping sound and flashing light that is unique to them.

Pressing Rockets

Note: Once again, as in the whistle projects, hand ramming with a mallet is never employed with these fuels and devices. Only a press equipped with a safety shield should be used to press these items. Fireworks Tips #121 detailed the construction of such a hydraulic rocket press. For small rockets, some folks use a manual arbor press to consolidate (press) the fuels.

Strobe Rocket Fuel

In addition to the whistle fuel I referred to above, one other fuel is necessary for these strobing rockets–strobe fuel. This fuel is very similar to the composition that was used to make strobe pots. Please study the methods and precautions that were spelled out in that essay.

This strobe fuel is what gives these rockets their distinctive popping sound and flashing light as they fly. But, strobe fuel alone is not powerful enough to make a rocket fly.

Back in the ’80’s, Doc Barr started playing with a basic strobe rocket, using a black powder fuel to boost the strobe fuel’s power. His results are chronicled on Page 58 of The Best of AFN II.

A funny and educational quote from Doc’s article is, “All rockets have the potential of exploding on takeoff, but these do it with an annoying frequency. About 1 out of 10 act more like an open-ended salute than a rocket. So ‘light fuse and retire quickly’ is my Eleventh Commandment.”

In the late 80’s and early 90’s, folks like Doc and Steve LaDuke started working with whistle fuels in rockets, resulting in the high-powered fireworks whistle rockets like I described in the whistle rocket article mentioned above.

Somewhere along the line, these rocketry pioneers had the bright idea to combine the powerful whistle booster fuel with the impressive strobing fuel, and the modern strobe rocket was born.

Traditionally, nitrocellulose (NC) lacquer is added to the standard white strobe composition specified in my strobe pot article. In his BAFN article, Doc Barr said he pressed his strobe fuel slightly dampened with NC lacquer. Many modern builders dampen their fuel with NC lacquer, granulate the dampened fuel through a 12-mesh screen, and dry the granules before pressing the fuel in the rocket motor.

Years ago I made a slight change in this method. Rather than using NC lacquer, I now dampen my strobe fuel with an additional 2% mineral oil dispersed in Coleman Fuel, as I described in the whistle-fuel procedure.

Chemical	Percentage	16 Ounces	450 Grams
Ammonium Perchlorate	0.57	9.15	257.1
Magnalium, 200 mesh	0.24	3.8	107.1
Barium Sulfate	0.14	2.3	64.3
Potassium Dichromate	0.05	.75	21.5
Mineral Oil	+0.02	0.3	9

Note: The ammonium perchlorate, barium sulfate, and potassium dichromate are each milled individually in a blade-type coffee mill until they are fine enough to pass through a 100-mesh screen.

Warning: Potassium dichromate is toxic and a known carcinogen. A good respirator and rubber gloves are required when working with this chemical, and when using it in pyrotechnic compositions. Don’t breathe this stuff or get it on your skin. Wear your protective gear even when you are pressing the finished fuel in the rocket motor.

I’ll be making 3/4-inch ID (one-pound) size, strobe rocket motors. Each motor will use about 39 grams of whistle fuel and 25 grams of the strobe fuel. So, the 450-gram batch of strobe fuel shown in the formula above will be enough for approximately 18 motors.

All the dry chemicals are weighed out individually, then mixed thoroughly by gently passing them through a 20-mesh screen or kitchen colander. I put this mixed powder into a small plastic bucket.

I weigh out the mineral oil into a clean quart jar, such as a spaghetti sauce jar, and then I add 1/2 cup of the Coleman Fuel to the oil. After tightly screwing the jar’s lid on, I shake the liquid to completely mix the two ingredients.

This mixed liquid is then added to the dry powder, and it is completely blended in with gloved hands. The damp composition is then dried over a pot of hot water, as described in the tutorial on making whistle fuel. Once again, the fuel is never brought anywhere in the vicinity of any open flame or source of sparks.

After a couple of hours of drying over the pot of warm water, the fuel will be dry, will stop smelling of Coleman fuel, and will resemble grayish-green sand. I use my gloved hands to break up fuel clumps as it is drying.

The Rocket Tooling

To make the 3/4-inch ID strobe rockets for this project, I’ll be using my tooling, which is very similar to the Skylighter TL1361 tool set. Strobe rocket tooling is almost the same as whistle rocket tooling. The main difference is the spindle is about twice as long. The number of rammers (”drifts”) can vary from tooling to tooling.

Just as I did in the whistle rocket project, I polish the drifts and spindle using very fine sandpaper and metal polish to facilitate removal of the drifts during the pressing.

Strobe Rocket Motor Tubes

Once again, because of the high pressures used to make these engines, and the high thrust they develop, I use the extra-strong TU1066 3/4-inch ID paper tubes. For these motors I cut the tubes 6 inches long.

The Tube Support

A 6-inch long, PVC plumbing pipe and band clamp tube support is used to reinforce the paper tube during construction.

Drilling the Fuse Hole

Just as I did with the whistle rocket motors, I drill a 1/8-inch hole through the side of the paper engine tube, right where the bottom of the fuel grain will be.

Marking the Tooling Drifts for Safety

At least 1/8-inch clearance is allowed between the spindle and the point where the drifts would contact it. I mark my tool drifts with masking tape to be absolutely sure they never pinch fuel between the drift and the spindle while the fuel is being pressed. Pinched fuel can explode upon pressing. That 1/8-inch clearance is enough to prevent this.

My particular tooling set only has one hollow rammer and one solid rammer. Some tooling comes with two or three hollow drifts, and each one must be marked with tape accordingly for safety.

Pressing a Strobe-Rocket Motor

The first thing I do in this pressing process is scoop out a paper cup full of whistle fuel, and a paper cup full of strobe fuel, set them aside and put the large tubs of my fuels away in safe storage. As I’ve mentioned before, this is perhaps the most important safety precaution: limiting the amount of exposed flammable composition when working with it.

For my strobe rocket, I press the whistle fuel in the tube in the same way and with the same pressures I did when making the whistle rocket motors. Pressing three 7-gram increments, and one 4-gram increment of the whistle fuel brings that fuel halfway up the spindle. These increments are pressed with the hollow rammer.

I use black rubber o-rings on my rammers to keep dust down to a minimum during the pressing. These o-rings, as seen at the top of the solid drift in the photo of the tooling above, also serve another purpose.

Each time the rammer is about to be reinserted into the tube, I slide/roll the o-ring down toward the end of the rammer. Then, as I insert and press the drift down into the tube, the o-ring seals against the top of the tube and prevents much dust from blowing out. When the drift is removed after that increment, the o-ring’s position marks where the top of the tube was, and just how far into the tube the drift went while pressing that increment.

When the drift is removed from the motor after an increment is pressed, the o-ring stays put on the drift exactly where the top of the motor tube was before the drift was removed.

Critical: I keep a full-scale sketch of the motor on my workbench as I’m pressing the motor. I’ll put the drift, with the o-ring marking where the top of the motor tube was, down on the sketch, and keep track of how high the pressed fuel is coming in the motor. In this way I can precisely determine when the whistle fuel is pressed up to the desired level, and switch to the strobe fuel increments.

I keep the hollow rammer cleaned out as I press the fuels, because I never want to be pressing fuel up inside the rammer, between it and the spindle.

Then I press three 7-gram increments of the strobe fuel with the hollow rammer, and one 4-gram increment of that fuel with the solid rammer, being very careful to not press past the safety-tape line on that rammer.

This brings my strobe fuel up to about 3/16-inch to 1/4-inch above the end of the spindle, as checked once again by comparing the drift and o-ring with my sketch. The final strobe fuel increment is adjusted so that it reaches that level.

This strobe-fuel distance above the spindle is critical. Too little strobe fuel will cause the motor to start its whistling delay burn too soon. Too much strobe fuel above the spindle will cause the motor to burn too long, turn back toward earth, and perhaps even return all the way to the ground before the heading bursts.

Note: Ask me sometime how I know about the effect created when too much strobe fuel is pressed above the spindle. The story deals with a six-pound strobe rocket coming back to earth, going through the roof of a meeting tent as there was a “parting of the seas” in the crowd, bouncing off a swimming pool diving board, and the heading explosion nearly scaring Doc Barr to death, or at least into regaining the memory of most of his previous sex life. Oh, I can laugh about it now, but it was damn embarrassing at the time.

After the strobe fuel has been pressed to that critical distance above the spindle, another two 7-gram increments of the whistle fuel are pressed above the strobe fuel, as shown in the sketch above. This whistle fuel section creates the whistling “delay” portion of the rocket’s flight before the ignition of the header.

As I mentioned in the whistle-rocket article, other “delay” effects can be produced. Colored fuels can be used instead of the whistle delay fuel, or titanium can be added to the whistle delay fuel. The amount of delay fuel has to be dialed in to produce the desired effect and length of flight.

The motor is then capped off with a 7-gram increment of bulkhead clay, with a passfire hole hand-twist-drilled into it. I never drill into whistle fuel with titanium in it, as I warned in the whistle-rocket article.

If I do use whistle fuel containing titanium in the delay section, I cap it off with 1/8-inch of fuel with no metal in it. Then I carefully hand-twist-drill the passfire hole.

Troubleshooting: The various amounts of fuel, and the distance up the spindle between the two fuels, have been dialed in for my own fuels and tooling. If your pressed rocket motor blows up on the launch pad, then less whistle fuel and more strobe fuel should be used. On the other hand, if your rocket doesn’t have enough power at launch, more whistle fuel and less strobe fuel should be used.

So, there we have it, a finished strobe-rocket motor. One final thing I’ll do is carefully re-enlarge the fuse hole with my awl since the hole can become a bit closed down and filled with fuel during the motor’s pressing.

Creating a Rocket Header

These rockets can fly so high that I really like to only use report headers on them. The effect of a star-shell header could get lost up at that altitude. As I showed with the whistle rockets, the hollow end of the motor tube can be filled with loose whistle fuel, perhaps containing some titanium, and then capped off to create a small report heading.

Loose strobe fuel, which is also a powerful explosive, can be used in this way, too. If more hollow space is desired, the motor tube can be extended with an extra piece of the same motor tube, glued and taped onto the motor tube to extend it.

For a larger, more impressive report heading, Skylighter’s PL1020 or PL1022 plastic #5 can shell casings can be used. These plastic cans measure slightly less than 2 inches in diameter, and work well on these one-pound rockets.

I fill the recess in the can’s cap with hot glue, drill a quarter-inch hole in the can’s bottom, and hot-glue a piece of quickmatch or fast fuse into that hole. When gluing the fuse into the can, I make sure all the gaps around the fuse are filled with glue to prevent any composition from leaking out of the can after it is filled.

The fuse will transfer fire from the top of the rocket motor to the heading.

Then I fill the can with my report composition of choice. The traditional filling would be flash powder, but making flash has become a bit problematic for some in the current legal climate.

If one has legal access to the necessary chemicals, I’ll describe a safe way to make a flash report with one of these cans. But first, I’ll detail three alternatives for making a report without flash powder.

A simple report can be made by filling the can with black-powder-coated rice hulls, with the addition of some coarse titanium if silver sparks are desired. One of the cans can hold 45 grams of the BP-coated hulls, and 14 grams of the titanium.

Two other alternatives would be to fill the can with loose whistle fuel or loose strobe fuel. A can will hold 57 grams of my whistle fuel, or 67 grams of my strobe fuel. For silver sparks, 14 grams of titanium can be added to either of these fuels by putting the fuel and the titanium into a small paper cup and gently swirling the two together to mix them before pouring them into the can.

Note: I mention this flash report composition option out of a sense of responsibility. Folks will make flash reports. There is a long tradition of it in all kinds of fireworks. But, flash powder is the most powerful composition that fireworkers work with, and many really serious pyro accidents involve it.

No matter which report composition I used, I then glued the caps onto the plastic casing cans with PVC plumbing cement from Home Depot. I did this outdoors because of the fumes, wiping the excess glue off with a paper towel.

I then strengthened the casings with some 1/2-inch wide fiberglass-reinforced strapping tape. Since my tape roll was 1-inch wide, I split the end of the tape in half. This allowed only one half of the width to tear off as I used it.

Note: During this taping process, the normal handling of the binary-mixed flash report is enough to sufficiently mix the ingredients. No rough shaking is necessary. Once the can is closed, handling this report is no more dangerous than the normal handling of a commercial fireworks salute.

I then finished the headings off with a layer of aluminum foil duct tape.

Here is a video of each of the four different report compositions, made as described above.

Attaching a Heading, Fuse, and Stick to a Strobe-Rocket

I first trim the header fuse so that it is long enough to go all the way through to the bottom of the passfire hole, and is pressed against the rocket’s fuel grain. I bare the last 3/4 inch of the fuse.

Then I put a bead of hot glue around the top of the motor tube and quickly install the header, carefully making sure the fuse goes all the way down into the passfire hole as I do so. I reinforce the joint between the header and the motor tube with an additional fillet of hot glue.

I’ve found that the slick side of a piece of the paper backing from the aluminum foil duct tape comes in handy for smoothing fillets of hot glue without burning my fingers.

The joint is then reinforced with some vertical, 3-inch strips of strapping tape, finished off with horizontal bands of the tape around the heading and the motor tube. This really strengthens the connection.

A 45-inch long, 5/16-inch-square, poplar rocket stick, with a beveled end, is then hot-glued and strapping-taped to the motor. If the rocket is to be flown immediately, then a 6-inch piece of Visco fuse is inserted into the motor’s fuse hole.

If I am going to store the motor for a while before launching it, I won’t install the Visco fuse now, but will instead seal the end of the motor and the fuse hole with aluminum foil tape to prevent the whistle fuel from absorbing moisture.

Well, it’s been a bit of a journey, but in the last 3 projects we’ve made whistle fuel, whistles, whistle rockets, strobe fuel, strobe rockets, and impressive report headings. While these powerful fuels and devices are not exactly beginner’s projects, if they are approached one step at a time, with good safe work habits, they can indeed be some of the most impressive and satisfying fireworking devices around, both for the builder and for the audience.

Stay Green and Have Fun,
Ned

How to Make Fireworks Whistle Rockets

What Is a Whistle Rocket?

I think a really impressive fireworks device speaks for itself, so here’s a video of one of these whistling firework rockets in action.

A whistle rocket does just that: whistles and screeches as it leaps skyward. The motor uses the same whistle fuel that was used in the “How to make a whistle” article. Whistling rockets are “hot.” They leap off the launch pad and can really reach a seriously high altitude if they’re made well.

I’ve made whistle rockets in sizes from 1/4-inch ID super-bottle-rockets up to 1.5-inch-ID “six-pounders.”

I’ve lifted some big ball shells (called “headings” when they’re carried by rockets) with the larger whistle rockets. But, often they fly so high that the effect of such a heading is lost. For that reason I prefer to simply put a large report heading on them with some coarse titanium in it for impressive silver sparks when the header explodes.

Other variations in construction can include various “delay” effects during the coasting portion of the flight following the initial powerful thrust portion–from simply allowing the rocket to continue whistling across the sky, to having the whistle change to a brilliant red flare or a color changing one, before the heading finishes the rocket’s flight.

Be aware, though, that whistle rockets are not your “father’s black-powder rockets.” The rocket fuel used in these babies is powerful. If the rocket engines are not dialed in carefully and fused properly, very impressive CATO’s (”bombs on a stick”) can result.

Warning: Do not EVER hand-ram whistle rockets using a mallet. The fuel is sensitive and could be set off in that process. Whistle rockets must be pressed using a manual arbor press for small rockets or a hydraulic press for larger motors, which require more pressure. It is wise to use a safety shield on a press just in case something goes wrong and the motor ignites during construction.

Whistle Rocket Fuel

I’ll be using the same fuel that I specified in the article on making whistles. The alternative fuels I mentioned in that essay can be used to make whistle rocket motors. But there will be the requisite “dialing in” in order to maximize performance and consistency with those variations.

So, study that article and make some of that whistle fuel, observing all the pertinent safety precautions.

Whistle Rocket Tooling

I will be making one-pound, 3/4-inch ID, whistle rocket motors for this project. Skylighter carries TL1311 tooling used to make these engines.

This tooling set comes with a base, a spindle, a hollow rammer for pressing the fuel increments around that spindle, and a solid rammer with which to press the increments of fuel above the spindle.

Note: You may notice the tooling I’m using in this project, which I’ve had for years, is different than the Skylighter tooling. But, my spindle is about the same size and the motor construction and performance are very similar.

Whistle Rocket Motor Tubes

Because of the high pressure at which the fuel is pressed in these motors, and the thrust they develop during flight, high-strength paper tubes must be used in their construction.

Skylighter TU1066 3/4-inch ID, 1/8-inch wall, extra-strong tubes are an excellent choice for these whistle rocket motors. I cut the 30-inch long tubes into 4.75-inch long tubes for these engines.

The Tube Support

Because of the high pressure used to press these motors, the tubes would bend, split, and collapse if they were made using no tube support. A good support is absolutely essential when making these motors.

A 4.75-inch piece of 1-inch ID, PVC plumbing pipe serves well as a tube support. It is sliced lengthwise with a hacksaw to ensure that it will go around the paper tube and fit snugly when the slice is closed. The support is held tight with metal band-clamps, installed side-by side, and tightened with their screw-adjusters alternated around the circumference of the support.

Polishing the Tooling

Unlike the fuels for charcoal tailed rockets, whistle rocket fuel tends to be “sticky.” The high pressures used to press the fuel around the spindle cause the fuel to adhere to it. This makes the motor hard to remove from the spindle once the engine is pressed. And the sodium salicylate fuel I prefer is reportedly stickier than fuels made with potassium benzoate or sodium benzoate.

Here is a solution, though, regularly touted by master-rocketeer Steve LaDuke. Polish your tooling, especially the spindle, using very fine, 600-grit sandpaper and a good metal polish. I got an excellent polish, Mothers Billet Metal Polish, at my local auto-parts store.

First, if I have any scratches or small imperfections on the spindle, I remove them using a small piece of the sandpaper to smooth the tooling. Sanding in a lengthwise direction on the spindle ensures any remaining scratches run in that direction, rather than in a circumferential pattern, which would make the motor-removal more difficult.

Then, using a small section of soft rag, the tooling, including the rammers, is polished until it all has a mirror-smooth finish. This really enhances the ease of use of the rammers, and the finished rocket motor’s ability to be removed from the spindle.

I even do the best I can to polish up inside the hole inside the hollow drift (”drift” is another word for “rammer”). This will help release any fuel which gets between that hollow part and the spindle during pressing.

Polishing the tooling this way is time well spent. It will help avoid a lot of aggravation in the next steps of pressing the motor and removing it from the spindle when it’s done.

Pressing a Whistle-Rocket Motor

Besides being pressed in a longer tube, and on a longer spindle, a whistle-rocket motor is not much different than a regular whistle. But I do fuse whistle rocket motors differently than I fuse standard whistles.

Drilling the Fuse Hole

You’ll note that the fusing technique shown in the diagram is different than most rocket fusing. There is a method to my madness.

The first thing you might notice is there is no clay nozzle in whistle rocket motors. A whistle rocket needs to have the bottom of its motor tube wide open. So the fuel has to be ignited right at its bottom edge, or else there’s a good chance the motor will blow up due to over-pressurization after ignition.

It can be a challenge to install a fuse from the bottom of the motor, only touching the edge of the fuel-grain, with no nosing to hold it in place.

Some folks hot-glue the fuse to the inside surface of the paper tube. Others use masking tape to attach the fuse to the rocket stick. I’ve tried both of those methods. With some care they can work fine, but at other times I’ve had the fuse fall off as it was burning, before igniting the motor.

So, I came up with the solution of installing the fuse as shown above. Before pressing any fuel, I drill a 1/8-inch hole through the motor casing, right at the outside edge of where the fuel grain will begin. I use a piece of wooden dowel to back up the inside of the paper tube during the drilling operation.

Marking the Tooling Drifts for Safety

Next, I mark the tooling drifts with masking tape to ensure they never come into contact with the spindle when I’m pressing a motor. I allow about 1/8-inch margin of safety between the drift and the spindle when I’m applying the tape.

Pressing Rocket Fuel into the Tube

The hollow drift is used to press the increments of fuel, until the fuel is above the spindle. All the increments are pressed to 7500-psi (pounds per square inch) on the composition.

In the article on making whistles, I illustrated the method for determining how much hydraulic press force to use with a solid drift. Applying 2200-psi of pressure according to my press’s gauge results in an actual 7500-psi on the composition with the solid drift.

But, since the hollow drift has the hole in it, less force will have to be applied to it to achieve this same pressure on the fuel.

With some math, I’ve determined that the surface area of the end of this hollow drift is about 80% of the surface area of a solid-end drift. For this reason, when using the hollow drift I’ll only apply about 80% of the force with my press that I’d apply when using the solid drift.

So, for the increments that are pressed around the spindle with the hollow drift, I’ll press up to a gauge reading of 1750-psi on my hydraulic press.

The first thing I do when pressing a motor is remove a small paper cup of the fuel from the tub of fuel. Then I close the tub tightly and set it aside away from where I am working. That way, only the small cup of fuel is exposed in case something goes wrong.

With the support securely fastened around the paper tube, and with the fuse-hole-drilled end of the tube mounted on the spindle, I introduce 7 grams (1/4-ounce) of the whistle fuel, using a funnel.

I then consolidate that fuel increment with the press in two steps, by first pressing up to only 1000-psi on the gauge.

I remove the drift and use the smooth, round end of my awl to clean any fuel that is wedged in there out of its hole. Then, I insert the drift back into the tube and press the rest of the way up to 1750-psi on the gauge.

If I press all the way up to the full pressure on the hollow drift in one step, fuel will work its way up between the drift and the tube, and between the spindle and the drift, in its hole. This can bind the drift in the motor, which makes it difficult to remove after the increment is pressed. Pressing the increment in two stages, and cleaning the drift between those two pressings usually eliminates stuck-drift syndrome.

When I’m pressing a really large motor, such as a 1.5-inch ID model, I’ll actually press each increment in 3 or 4 stages to reach the full pressure in order to keep the drifts from getting stuck.

Four, 7-gram increments of the fuel, pressed in this manner with the hollow drift, bring the fuel to just above the spindle, using my fuel and tooling. This can vary a little from batch to batch of the fuel, or with different tooling.

After the fuel is above the spindle, I switch to the solid drift. Now I press the same 7-gram size increments in one pass up to the full 2200-psi reading on my gauge.

For the rocket shown in the initial video in this article, I press fuel to one inch above the spindle. That requires three 7-gram increments with the solid drift, for a total of 49 grams of fuel in this motor.

I cap the motor off with a 7-gram increment of bulkhead clay mix.

Adjusting the Total Flight Time of the Whistle Rocket

The portion of the rocket’s flight after the initial high-thrust phase, and before the heading bursts, is called the delay section of the flight.

The fuel around the circumference of the spindle, and above it for that same distance, about 1/4-inch, burns very rapidly in the highly pressurized thrust period of the rocket motor’s burn.

Then, the solid portion of the fuel above that thrust fuel burns more slowly in a less pressurized environment. That’s why the whistle sound changes so drastically after the initial thrust burn.

So, in this rocket motor I had 1/4-inch of thrust fuel above the spindle, and then about 3/4-inch of delay fuel above that. If I shorten that delay fuel, the delay portion of the flight would be shorter. If I lengthen the delay fuel column in the motor, that delay portion of the flight would be longer.

Looking at the video at the beginning of this article, the one-inch of total fuel above the spindle produced that particular flight and delay before the heading exploded. I was pretty happy with that rocket’s flight. I might have lengthened the delay fuel column another 1/4-inch to see if that produced a more pleasing flight in the next rocket.

Other interesting modifications can be made to the delay fuel grain. Once the fuel has been pressed to above the spindle, spherical titanium can be added to the fuel increments that get pressed with the solid drift. The delay fuel is weighed into a paper cup. I add 10% of that fuel’s weight in titanium. Then the cup is swirled to mix the components.

The titanium fuel mix is pressed one increment at a time, the same as described above. The metal will produce a silver spark trail as the delay-fuel burns. If the hard metal is added to all the fuel (below the top of the spindle), it will tear the spindle up pretty quickly. Since it also might pose a sparking threat, I only add it to the delay fuel.

If I plan to have a passfire hole, I usually drill the hole down through the center of the clay bulkhead into the fuel. But, I don’t want to drill into any fuel containing titanium; so I’ll cap any titanium-fuel off with 1/8-inch of plain fuel (no titanium in it). Hand-twist-drilling into that is safer.

The effects you can create using the delay fuel are limited only by your imagination. For instance, in his article “How to Make Fireworks Rockets with Green and Red Tails,” Dave Stoddard describes delay fuels used to change the rocket tail’s color to a green or red flare as it flies upward.

Removing the Tube-Support from the Tube, and the Motor from the Spindle

After the fuel and clay have been pressed in the tube, it’s time to remove the motor from the spindle. This is easier if the support is removed from the engine first, which loosens the motor on the spindle just a tad.

First, I loosen and remove the metal band-clamps from the support, and then slide the PVC support off of the motor.

Then the motor is twisted off the spindle. Putting the spindle base in a vise or holding it rigidly in the rocket press can facilitate this. Using both hands to twist it, the motor is carefully removed from the tooling. Do not use clamps or pliers on the motor itself, or you will risk cracking the fuel grain, which will cause the rocket to explode instead of fly.

Drilling Passfire Hole into Clay Bulkhead

If I am going to put a heading on the rocket, then I’ll need a passfire hole in the clay bulkhead to transfer fire from the last of the rocket fuel to the heading.

I create this passfire hole by carefully hand-twisting a drill bit into the center of the bulkhead just through the clay into the pink fuel. (Remember that the last 1/8-inch of fuel that was pressed should contain no titanium, even if titanium was added to the rest of the delay fuel.)

Warning: Never use a power drill to create the passfire hole. The friction and heat caused by such fast drilling could ignite the motor. Only use hand twisting on the drill bit to create the hole.

I’ve found that starting the hole with a sharp 1/8-inch drill bit, hand twisted through the clay until it just barely penetrates the fuel, works well. Then I’ll expand the hole with a 1/4-inch diameter bit to widen and create the final passfire hole.

Simple Rocket Headers

Several types of simple headers can now be employed on this whistle rocket.

There is a 1-inch long empty space in the motor tube above the drilled clay bulkhead. First of all I like to insert a couple of pieces of black match, from either quickmatch or fast-fuse, into the drilled bulkhead passfire hole. I cut these pieces of match about 1.5-inches long so they reach the bottom of the passfire hole, and extend just to the end of the motor-tube.

These strands of blackmatch ensure positive fire transfer from the last of the rocket-fuel to the header.

For a spray of stars at the end of the rocket’s flight, a small amount of black powder can be put into the tube’s recess, followed by some of the stars.

For a falling glitter comet, some of the black powder followed by a single 3/4-inch comet can be used to fill the end of the motor.

For a small report at the end of the rocket’s flight, the end of the tube can be filled with either loose black powder or loose whistle fuel. A pinch of coarse titanium can be added to either of these powders to produce silver sparks when the header fires.

With any of these types of headings, the motor is then capped with a 1-inch end disk, glued on.

If a report heading has been made, I like to reinforce the report tube-section and end cap with some strapping tape, finished off with some peel-and-stick aluminum-foil duct tape. This reinforcement really helps a report heading to “pop.”

For a star or comet heading, simply gluing a paper disk on is sufficient to finish the end of the motor.

Installing Rocket Stick

The last step to finishing this rocket is to install the stick. I’m using a square poplar stick that I ripped on my table saw. It measures 5/16-inch square by 36-inches long. I bevel the end of the stick, hot-glue it straight on the motor, and finish the attachment with two bands of strapping tape. I make sure the stick does not cover the fuse-hole.

A 6-inch piece of Visco fuse can now be inserted into the fuse hole, and the rocket is ready to be placed in a launch tube and flown.

Sealing the Rocket Motor for Storage

If I’m going to store the finished rocket for a while, I like to seal the bottom of the motor and the fuse-hole with some aluminum-foil duct tape. This prevents the hygroscopic rocket fuel from absorbing atmospheric moisture during storage, and protects the motor from flame or sparks until flight-time.

Prior to flight, the tape is completely removed from the motor’s bottom, and the Visco fuse is installed through the fuse hole.

Motors without sticks can be stored in sealed plastic baggies along with a bag of desiccant to ensure they do not absorb moisture.

Conclusion

Well, there you have it–one of the most interesting and powerful rockets you can make.

Next time I’ll show you a nice variation on this basic motor, the strobe rocket, and some different ways to create a rocket heading.

See ya then,
Ned

How to Make Pyrotechnic Whistle Mix

Weighing and Screening Pyrotechnic Chemicals

How to Make a Hydraulic Rocket Press

In my experience, there are three basic machines, which become necessary as one gets deeply into fireworking: a ball mill, a star roller, and a hydraulic press. Ball mills were discussed extensively in Fireworks Tips #91, and I showed some options for star rollers in #92. Now it’s time to look more deeply at rocket presses.

Commercial Rocket Presses

In past newsletters I have shown several of my hydraulic presses in action as I’ve made rockets, comets, pressed stars, black powder pucks, or fountains.

Some devices, like simple gerbs or black powder rocket motors, can be made by simply hand-ramming them with a rawhide mallet and a pounding post. Or they can be pressed with a hydraulic press.

Other devices such as whistle rockets or strobe rockets utilize more sensitive fuels, and require hydraulic pressing for their manufacture. Hand-ramming these motors is simply asking for a disaster.

Since I’m about to present projects showing how to make whistles, whistle rockets, and strobe rockets, I thought an introductory essay on hydraulic presses would be in order.

In the previous articles mentioned above I’ve shown my small Hobby Fireworks press. It’s a nice press and was not too expensive. It sits on top of my workbench and is light and portable. I can take it to club events like the PGI convention. Unfortunately, Hobby Fireworks has gone out of business.

Over the years I made some modifications to the press so that it suited my needs better. I replaced the 1/4-inch-thick steel plate on the top of the bottle jack with one that is 3/4-inch thick. The thinner one started bending a bit, and I want that plate to be perfectly flat.

I replaced the original 4-ton bottle-jack with a fast-action 6-ton one. The new jack can exert forces up to 12,000 pounds, which is about all I ever need, even when pressing large 4-inch comets and large rockets. Additionally, the new jack raises very quickly compared to standard-lift models.

The jack is available at Northern Tool, and currently it sells for $28, including a nice, collapsible lug wrench.

When I showed an advance copy of this article to my friend, Dan Creagan, he sent me a photo of a jack he had just found at WalMart, apparently identical to this one except it was painted black and had the Torin Brand name on it. It only cost Dan about $19.

I had the welding shop reinforce the press’s adjustable cross “bridge” so that it would withstand the additional force exerted by the 6-ton jack.

I drilled holes in the back of each horizontal leg-support so that I could bolt the press down to the workbench to secure it during use.

The pressure release knob had a hole drilled through it and a 3/16-inch rod-handle installed for fast and easy operation.

This press has gotten a lot of use over the years, and if I had welding capabilities and I wanted a nice little press, I’d duplicate this model.

There are H-frame shop-presses available at various suppliers. In the past I’ve referred to one such press sold by Greg Smith Equipment. It’s a floor standing unit, and weighs over 150 pounds, but it looks like a pretty nice press, has a good range of adjustability, comes with a pressure gauge, and sells for only slightly more than $200.

Simple Do-It-Yourself, Hydraulic Press

Note: My friend, Jim B, has a favorite saying; “For every 10 pyros, you’ll get a dozen different ideas on how to do any task in pyro.” The ideas I present in the following project are designed to simply get your creative juices flowing. I seriously doubt anyone will build a model that is exactly like mine. But maybe these ideas can point you in the right direction.

In addition to the commercially-manufactured options described above, I got to thinking about a sturdy, relatively lightweight, bench-top press which did not require much welding. I’ll describe one possibility that came to mind.

The setup and operation of the hydraulic bottle-jack is similar to the Hobby Fireworks press. I had six, 4×4-inch, 3/4-inch-thick, steel-plate shims cut at my local steel supply, to augment the adjustability of the press. Between the 5.5-inch travel of the bottle jack’s piston, and the 4.5-inches of adjustability the shims provide, the press has a total of 10 inches of travel between all the way down and all the way up.

This allows me to adjust the press’s top plate with the hex-nuts only one time per the particular device that I’m pressing. I never needed more than that 10 inches of adjustability for any of the devices I make. I’ve tripled-up the top hex-nuts because of the forces they endure during pressing. I don’t want to be stripping any threads.

The Press’s Main Frame:

The main frame of the press is made from four 3/4-inch x 36-inch threaded rods, nuts and washers from Home Depot. I had my local steel supply-house cut the bottom and top plates, which are 12-inch long pieces of 1-inch (thick) x 9-inch steel plate.

One-inch-thick steel plate is obviously very strong, and that strength is necessary to withstand the forces, which will be involved in pressing fireworks devices. I wouldn’t want to use steel plates that are thinner than the ones I used, and I also wouldn’t want to make them larger and spread the threaded rods out farther. This could lead to bending the plates.

The PVC plumbing pipe sections on the threaded rod uprights are there to keep me from cutting my knuckles on the threaded rod as I insert and remove devices in the press.

Installing a Blast-Shield

When I’m pressing whistle or strobe rocket motors, which use pressure sensitive, powerful fuels, the installation of a blast-shield is a good idea. The 1/2-inch thick plastic sheet will offer some protection just in case a motor “goes off” while it is being pressed.

The blast-shield is attached to the press and held in place with 3/8-inch eye-bolts, large fender washers, and hex nuts. Polycarbonate plastic such as Lexan is used in bullet-resistant windows, and serves well for blast-shields.

The other benefit of the PVC pipe on the threaded rods is to hold up the bottom blast-shield, eye-bolt supports.

Jack Return Springs

The two 7-inch springs, also from Home Depot, serve to return the bottle jack to its “down” position when the pressure-relief valve is opened. The top of each spring is attached to the 4×4-inch plate that is welded to the screw-out jack-post. The bottoms of the springs are attached to eye-bolts that are mounted in holes drilled through the bottom steel plate.

I had my welding-shop weld on small hex nuts for the top spring attachment at the same time they welded the plate to the jack post. This was the only welding required in this project.

Pressure Relief Valve Handle

To create an easily-operated handle for the jack’s pressure-relief valve, a hole was drilled through the end of the relief valve. A piece of 3/16-inch galvanized steel rod, bent in an L-shape was inserted through the hole, and the small end was pounded flat on a vise-anvil to hold it in place.

Holes in the Steel Plates

The holes in the top and bottom steel plates were drilled using a drill-press. That was the only large piece of equipment that was necessary in the fabrication of the rocket press. The threaded-rod holes were drilled at 9.5-inch centers, side to side, and 5.5-inch centers, front to back.

The jack is attached to the bottom plate with three, 5/16-inch bolts, which go up through the steel plate and into holes I drilled and tapped in the bottom of the jack. (Threading holes in metal is done with a tool called a “tap.”)

Two extra holes were drilled toward the back of the bottom steel plate, through which bolts will go to attach the press to my workbench. This will make the press nice and steady as I’m pressing rockets.

I used a hand-held grinder to smooth all the edges and corners of the steel plates. Then I primed and painted the plates using spray primer and finish paint.

Hydraulic Pressure Gauge

There are a few pressure-to-force (PtoF) hydraulic pressure gauges available to the pyro-hobbyist community. These gauges employ a one-square-inch-area piston, so they directly read out the number of pounds of force being applied to the item being pressed.

For example, if the PtoF gauge is reading 2000 psi, the actual force being applied to the tooling is 2000 pounds, the equivalent of 2000 pounds of concrete sitting on top of the tool.

An advantage to using one of these gauges is that you won’t need to install a pressure gauge on the press’s bottle jack.

I personally like to use a gauge that is actually installed in the bottom of the bottle-jack. Doing so enables me to eliminate one loose, movable component, like the PtoF gauge, when I’m aligning and pressing devices in the press.

Using a gauge on the jack, though, requires that the gauge’s reading be multiplied by the area of the jack’s piston, in order to determine the actual force being exerted by the jack. I’ll show what that means in a minute.

Installing a gauge on the bottle-jack presents what is probably the most challenging aspect of this project–drilling and tapping/threading the bottom of the bottle-jack, and installing a hydraulic pressure gauge. But, it’s good to know how to do this, even if a PtoF gauge is going to be used.

Installing a gauge on a bottle jack requires the partial disassembly of the jack, drilling a couple of holes, tapping/threading the hole where the gauge will be installed, cleaning debris out of the jack, and reassembling it.

One of the nice things about the bottle-jack I’m specifying in this project is that it is relatively easy to take apart and put back together.

First, the rubber drain/fill plug on the back of the jack’s cylindrical body is removed, and the oil that fills the jack is emptied into a clean pot. This oil can be filtered through a coffee filter and reused in the jack when it is reassembled.

When draining the oil, it helps to remove the pressure-relief valve. This valve has a 1/4″ steel ball bearing down in the hole into which it is screwed. Carefully set the ball and valve aside, and finish draining the oil. Pumping the lever assembly a few times works the rest of the oil out. Now is a good time to drill the hole in the pressure-relief valve and install the L-handle.

The lever-arm has a couple of steel pins, held in with spring-clips, and is easily disassembled. (You are making mental notes of how all this goes back together, right?)

It’s time to remove the large hex-nut at the top of the jack now. This requires that the base of the jack be held securely in a vise or a rocket press. (Waitaminnit, I’m making my rocket press! How can I hold the jack in my rocket press? I have 3 presses, and this will be my fourth.)

The hex-nut is then loosened with channel-lock-pliers or a large pipe-wrench. It may be necessary to whack the wrench with a rubber mallet or similar heavy object. The nut is screwed off when it is loose, and the central jack piston and outer jack shell-body can also be removed. The nut has a plastic O-ring gasket on it where it hits the main body, but this gasket is usually “glued” on with paint and does not need to be removed.

There is a “tapered” large rubber O-ring which sits in the groove that the shell-body came out of. Remove this O-ring. Remember that it was in there with the thin edge up, and the wide edge down.

Inside the jack, there will be a small, wire-mesh filter shoved in one of the holes in the base. Make a note of which hole it’s in, and then remove it. Actually, this is a good recommendation, which has never worked for me in real life. Each time I’ve disassembled a jack, the filter has dropped out before I get to notice where it was in the first place. I’m not sure how they get the darn thing to stay in during shipping and/or operation.

I’ll show in a moment how to determine which hole the filter ought to go back into when the jack is reassembled.

The screw-post will only unscrew so far as it extends out of the jack’s piston. It is not necessary to remove this screw-post all the way. The whole jack can be taken to the welding shop when the 4×4 plate is welded to the screw-post. If one wants to remove the post all the way, some filing/grinding is necessary to remove the small “indents” which have been knocked into the top of the cylinder to hold the post in place.

Now is a good time to measure and make note of the diameter of the bottom of the piston. In this case it measures 1.375 inches. Squaring half that diameter (the radius) and multiplying that by Pi (3.1416) yields an area of the bottom of the piston of 1.5 square inches. (3.1416 x .6875 x .6875 = 1.5 square inches)

Because of that, when my new, jack-mounted pressure gauge is reading, say, 1000 pounds-per-square-inch (psi), I’ll multiply that gauge’s reading by 1.5 to determine the actual amount of force the jack is exerting on the tooling in the press, which in this example would be 1500 pounds.

Once again holding the base of the jack in a vise or rocket press, I now carefully use a pipe wrench to loosen the jack’s inner cylinder. I apply the wrench right down at the bottom of that cylinder in order to avoid crushing or distorting the tube as I loosen it.

Once the inner cylinder has been removed, another plastic O-ring gasket can be seen inside the base where the cylinder bottoms out. This O-ring does not need to be removed. Notice that there is a top and a bottom to the inner cylinder. The top is beveled on the inside lip to make insertion of the piston easy. The bottom has a flattened edge, which bears on the O-ring seal.

The small lever-operated jacking piston/cylinder should also be removed at this time. There is a metal washer and a 1/4″ steel ball down in the base’s recess which should also be removed.

And, now, finally we’ve arrived at the final disassembly step. There is another 1/4-inch metal ball in the bottom recess of the base, held in with a plastic retainer. This can be seen in the base’s large recess in the photo above. The retainer is removed by prying it with a screwdriver, and the ball is also removed.

I’m keeping all the little parts in a clean paper cup to prevent me from losing them as I go along.

There is also an over-pressure, safety relief valve, covered by a plastic cap. This assembly, including the cap, screw-out post, spring, metal-mushroom, and very small metal ball, is all removed and placed in the paper cup.

I can just hear ya hollering, “Crikey, Ned, what the heck have you gotten me into?”

It’s really not as bad as it all sounds and looks. If you keep track of all the little parts, and remember how they all go back together, this can be fun. Really! There’s learnin’ happenin’ here.

At this point, for my own education, I spent a bit of time envisioning how the jack works when it is being operated. The small jacking-piston and cylinder create high pressure using the principle of mechanical leverage. The pressurized oil is forced through the small hole in the bottom of that recess and up past the ball/hole/retainer in the large base recess.

All those balls in this device simply act as valves, sitting in nicely machined recesses, and only allowing oil to flow in one direction, pushing the ball slightly out of its recess. Oil pushing from the other direction forces the ball against the machined seal and shuts off the flow.

As it is needed, more oil is “sucked” into the small base recess from the main reservoir between the outer jack body and the inner cylinder.

The pressure in the cylinder jacks the piston up a small amount. The process is repeated as the piston gradually is lifted.

If too much pressure is generated inside the main cylinder, the oil can push the small ball and spring in the over-pressure relief valve and allow the excess oil to escape back into the main oil reservoir between the outer jack body and the inner cylinder. This acts as a safety to prevent the jack from being over-pressurized and dangerously rupturing.

And finally, when we want the jack to retract and go down, the pressure-relief valve is loosened. This allows oil to move past the ball at the bottom of that valve, and back into the main reservoir.

Since the only hole through which oil moves out of the main reservoir is the one leading to the bottom of the jacking-cylinder’s small recess, that is the hole that the small filter will be replaced into (so it functions to remove debris from the oil as it circulates). I find which hole that is by blowing into it to make sure the air is coming out of the ball-blocked hole in the bottom of the small base recess.

And, keeping debris out of the whole jack is why I’ve completely disassembled it. After the next drilling and tapping steps are completed, all the parts will be completely cleaned before any reassembly. Small bits of metallic debris are the enemy of a properly functioning jack. They can become lodged in the various ball-valve assemblies and allow slow leakage, preventing optimal performance.

Drilling and Tapping the Jack-Base to Receive the Pressure Gauge

You’ll notice, when looking at the jack base, that all the existing holes and inner “channels” that the oil flows through are located in the right side of the base.

Conveniently, this jack’s base has a nice flat area on its left side, and plenty of room on the left-inside of the large recess where a hole can be drilled.

This is the point we’ve been heading toward. I want to drill a 3/16-inch hole down from the bottom-inside of that main base recess, but not all the way through the base. I drill this hole about 3/8-Inch deep.

I want to drill in from the left-outside of the base with the same 3/16-inch drill bit, until that hole hits the first hole that was drilled. I only want to drill as far as that first hole so that I don’t hit any of the other inner channels in the base.

The hole coming in from the side is drilled high enough from the bottom to allow the fittings I’m going to install later to clear the press’s base plate. I also plan that hole so that it is centered in the bottom “thickness” of the base, so that the strength of the remaining metal surrounding my new fitting is maximized.

Drilling this hole, centered up 1/2 inch from the bottom of the base, accomplished all the above goals. And it kept the metal thickness between the hole and the bottom of the base no less than 5/16 inch, which is needed to withstand the internal jack pressures.

These two holes are gradually deepened until they hit each other, and no further.

The two holes will form a new channel which will allow the pressurized oil inside the inner jack cylinder to reach the new gauge which will read out the same pressure that exists inside the cylinder.

Warning: The main power tool I’m using in this process is a drill-press. Like Norm Abrams says, “Read and understand the safety precautions concerning this tool before you use it.” I do this drilling at low speeds. I firmly hold the piece I am drilling with a clamp and/or other tools. This drill-press can be my best friend, or it can slice my hands open and/or break bones. Be careful.

The hole in the side of the base is enlarged with a 5/16-inch drill bit (Q drill bit) enlarging a section about 3/4-inch deep. This side hole (only) then has threads cut in it with a 1/8-inch-pipe-thread tap.

This is also a good time to drill and tap the bolt holes, in the flanges on the base, which will attach the jack to the press’s bottom steel plate.

There, the hard part, the machining, is done. I now clean all the debris, excess paint, and metal shavings off of all the parts in a pot of clean kerosene or paint thinner. I pay special attention to the base to make sure all the small metal debris has been washed off of it and out of all its holes and channels.

After the parts have dried, the bottle jack is reassembled in the reverse order in which it was taken apart. Before adding the oil back into it, I attach the new pressure gauge using hydraulic fittings and Teflon tape. My local hydraulic-fitting supply-house was able to supply the fittings that I needed, and which would handle the pressure the jack will be exerting.

These fittings were inexpensive, and it pays to use fittings certified for hydraulic pressure, rather than plumbing fittings which might rupture under that pressure.

The gauge sells for about $22 at McMaster-Carr. It is a 2.5-inch diameter dial, glycerin filled, 0-10,000 psi range, 1/4-inch pipe-thread bottom-connected, Model #4053K16.

But, the same supply-house where I bought the fittings, had a very similar gauge for only $16. I bought one for a spare while I was there.

I have temporarily hooked up gauges to lower-pressure jacks with iron pipe fittings. But those plumbing fittings are not rated for the 8000 psi that will be developed in this new jack when it is putting out the full 6 tons of force.

Remember that when the gauge reads 8000 psi, that reading is multiplied by 1.5 to determine the force that the jack is exerting. That means an 8000 psi reading equals 12,000 pounds of force, the maximum force this jack is rated for. That’s why I chose a gauge with a range of 0-10,000 psi.

The Teflon tape is carefully wrapped on the pipe threads, in the direction that will tighten the tape wraps as the male threads are screwed into the female fittings. 4-5 wraps of the tape are put on each threaded section. I’m careful not to overlap the tape down onto the end of the fittings, where bits could break off and clog the channels or valves in the jack.

After the gauge was installed and all the fittings tightened up, I filtered the oil through a coffee filter and filled the jack back up with the oil through the fill hole on the back of the jack’s body. I pumped the jack up and down a few times to work any trapped air out of the system. Then the jack was installed on the rocket press.

I topped the oil off with more, new hydraulic-jack oil until it started to run out of the fill-hole in the main jack body. Then I installed the rubber plug.

I put my Pressure-to-Force gauge on the jack-plate, and jacked the press up to various pressures. This was to make sure that, indeed, the PtoF gauge read 1.5 times what the gauge on the bottle jack was reading. I also removed the PtoF gauge, and jacked the press up to its maximum pressure and let it sit there for a while to make sure it wasn’t losing any pressure through leaks or badly sealed steel-ball valves.

Everything worked great, so I moved the press into its permanent location on my work bench and attached it there with bolts which go through the two extra holes in the back of the bottom steel plate, and on through the workbench top.

Conclusion

Great! My fourth press is now up and running. Why the heck do I need four presses? I think I’ll paint and clean up my old Hobby Fireworks press and see if I can find a new pyro who wants to give it a good home.

There’s one final thing I thought about this press when it was done: “Hey, I built that thing. I know every part of it, and if anything goes wrong with it, I know how to fix it.”

I bought an extra bottle jack while I was working on the project, and drilled and tapped it at the same time as the main one. That way I have replacement parts, or the whole complete replacement jack if necessary.

This all results in a good feeling, and I suppose that’s why I do all of this in the first place.

Stay Green, and now on to more, ahh, Pressing matters.

Ned

How to Make Flashing Fireworks Strobe Pots

Introduction

Close your eyes and listen to this music. What do you see when you do so?

Click here to listen to The Who

If you don’t see a large fireworks mine-shot, followed by a line of 30-second strobe pots, ending with another large mine-shot, then you really need to be subscribed to the Quilting-101 newsletter instead of this one on making homemade fireworks.

Man, that music gets me in the mood for strobes. The first mine-shot would grab the attention of any fireworks-display audience. Then the soft and subtle section of strobes would calm them down and get them ready for their emotions to build during the show.

Strobe pots are among the simplest of fireworks devices and are easy to make. They can really add some of that low-level variety to a pyro-display that so helps to keep an audience’s attention.

“Hey, here’s something different,” they’ll say to themselves as they stop, settle in, and start to pay attention.

How do these pyrotechnic “twinklers” work?

It is not necessary, of course, to have a scientific understanding of strobes in order to make them. Like baking a loaf of bread, chemistry is not necessary. All you need is a recipe, the right ingredients, and a feel for the proper ways to manipulate those ingredients.

But, for the scientifically minded, there are a few informative resources, which explore the strobe phenomenon in depth. In the 1979 edition of Pyrotechnica, Number 5, Robert Cardwell, the editor and publisher of the Pyrotechnica series, wrote an article, Strobe Light Pyrotechnic Compositions: A Review of Their Development and Use.

In this essay, Cardwell explores the historical development of strobing compositions and presents quite a few different formulas.

Dr. Takeo Shimizu, in Fireworks, the Art, Science and Technique (FAST), originally published in 1981, writes about “Twinklers,” which is how he refers to strobing stars. He presents an outline of the development of these strobing compositions, progressing during the second half of the 1900’s.

Specifically Shimizu writes, “In Germany, U. Krone and F. W. Wasmann suggested that a twinkle composition consists of two kinds of compositions mixed with each other, i.e. a smolder composition and a flash composition-Ammonium perchlorate smolders when it is mixed with a small quantity of magnesium. This can be used for the smolder composition. A mixture of magnesium and sulfate flashes when it is heated to a high temperature. This can be used as the flash composition.”

So, interestingly, a strobe composition is actually a mixture of these two types of comps, a smoldering one and a flashing one. When the mixture is lit, the first one begins to smolder. When the heat rises high enough, the flash comp ignites and emits a flash of light and heat. Then the mass returns to the smoldering state until the heat rises high enough to repeat the flash.

In some compositions, magnesium-aluminum (magnalium) is used instead of the magnesium. Magnesium requires a coating to prevent it from prematurely reacting with the oxidizer in the comp.

Additionally, sometimes barium nitrate or other oxidizers are used instead of ammonium perchlorate.

In 1987, John “Skip” Meinhart offered some details about his noteworthy strobing star formulas in Pyrotechnica XI. Except for Shimizu’s White formula, and Skip’s Pink formula, all the rest of the formulas use magnesium as the metallic fuel ingredient.

In the 1992 Pyrotechnica XIV edition Jennings-White explores Blue Strobe Light Pyrotechnic Compositions. Up until that point in time, blue strobes had not been explored in depth because of some unique problems associated with the chemical mixtures required to produce that color in a strobe.

All of this information ought to be able to keep you reading until late into the night if you are so inclined.

Making strobe pots

I won’t be focusing on making strobing stars in this project, but only simple, ground-effect strobe pots.

I’m also not going to be making any of the formulations, which contain magnesium. As I said, using that metal requires a special coating process because it does not form an oxidized protective layer on its own, as do aluminum or magnalium.

There seems to be some debate as to whether or not magnalium needs to be treated and coated when it is used in compositions containing ammonium perchlorate. Meinhart states, “I have had success using magnalium powders that have not been treated with potassium dichromate. In practice I have often used treated metal powders, but this does not always seem to be necessary.”

Whereas in Hardt’s Pyrotechnics, Barry Bush notes that the formulas he cites which contain magnalium or magnesium in combination with ammonium perchlorate do “require the metal powders used to be treated with potassium dichromate.” Shimizu also specifies treated magnalium, and details the methods of treatment in FAST.

Shimizu does state that if there is any reaction between magnalium and ammonium perchlorate, which would be encouraged by the presence of water, it would only be a slow reaction in which the metal is affected gradually.

I have used untreated magnalium in these formulas, with no problems. One sign of an unwanted reaction would be the heating-up of the composition as I’m working with it, so I always pay attention to see if that is occurring. I avoid adding any water to such a composition. I also don’t store these devices for long periods of time, which could produce a slow reaction of the ingredients, especially in the presence of moisture.

So, I think I’ll make simple white and pink strobe pots. The white formula is the most commonly cited one:

White Strobe Composition

Chemical	Percentage	16 Ounces	450 grams
Ammonium perchlorate	0.57	9.15 ounces	257.1 grams
Magnalium*	0.24	3.8 ounces	107.1 grams
Barium sulfate	0.14	2.3 ounces	64.3 grams
Potassium dichromate	0.05	0.75 ounces	21.5 grams

* Shimizu specifies 80-mesh, whereas other sources specify 100-200-mesh. The mesh of the metal is known to vary the flash rate of the strobe, so some experimentation is in order. Initially, I’ll be using 200-mesh magnalium, Skylighter #CH2072.

Barry Bush has an interesting note in Pyrotechnics concerning this formula. This formula “may be given a faster frequency by replacing the barium sulfate with anhydrous magnesium sulfate. The resultant fast strobe is sometimes called a “shimmer effect.” I’ll have to try this sometime in aerial-shell strobe-stars, since it is an effect I have admired in commercial shells.

Additionally, the flame created by this “white” composition is brilliant, but it does have a very slight green tint caused by the barium. Barium normally produces very green flames with the addition of a chlorine donor such as parlon or saran. Another experiment would be to include small amounts of these chlorine donors to shift the color of the white strobe pots to green.

The pink strobe pot composition is as follows:

Meinhart Pink Strobe Composition

Chemical	Percentage	16 ounces	450 grams
Ammonium perchlorate	0.57	9.15 ounces	257.2 grams
Magnalium, 200 mesh	0.15	2.45 ounces	68.6 grams
Strontium sulfate	0.11	1.85 ounces	51.4 grams
Strontium carbonate	0.08	1.2 ounces	34.3 grams
Parlon	0.04	0.6 ounces	17.1 grams
Potassium dichromate	0.05	0.75 ounces	21.4 grams

All the chemicals (except the magnalium, which I don’t put through fine screens) are fine enough to pass through a 100-mesh screen. If they are not, they are milled individually in a blade-type coffee mill.

Note: Ammonium perchlorate does not play well with potassium nitrate. The combination forms ammonium nitrate, which is very hygroscopic, attracting moisture out of the air like crazy, rendering any mixture or composition containing it wet and useless. Don’t grind either of these chemicals in a coffee mill which has been used on the other chemical, unless the mill has been thoroughly cleaned with soap and water.

Warning: Potassium dichromate is toxic and a known carcinogen. A good respirator and rubber gloves are required when working with this chemical, and when using it in pyrotechnic compositions. Don’t breathe this stuff or get it on your skin.

All the chemicals for a given formula are weighed out individually and are passed through a 20-mesh screen 3 times to thoroughly mix them.

Then the composition is mixed with enough nitrocellulose (N/C) lacquer (Skylighter #CH8198P) to create thick putty, similar to Play-Do. I did not dilute the lacquer, but used it right out of the can, as-is. The one-pound batches required 3 ounces, by weight, of the lacquer.

I started mixing the composition in a plastic tub with a paint stir-stick, and finished by kneading it with gloved hands.

The dough is then pushed with gloved fingers into paper tubes to create strobe pots. I start this process by pushing the tube into the composition-putty to get the filling started.

Large pots can be made with 1.5-inch ID tubes, cut into 1.5-inch long sections. Or, smaller pots can be made with 3/4-inch ID tubes, cut into one-inch long sections, or even longer. While thicker-walled parallel tubes, like rocket tubes can be used, strobe-pot tubes do not need to be super-strong, so spiral-wound tubes like Skylighter #TU2142 or TU2053 can be used.

Large diameter strobe pots would be appropriate for large displays and venues. Smaller ones are nice in backyard size shows. Varying the length of the paper tube will adjust the total burn-time of the strobe pots, so their duration can be dialed in for specific uses.

For this project, I think I’ll make mostly 3/4-inch ID by 1-inch long strobes to determine how well they are working and how long they burn, plus a few other sizes to see how they perform, too.

Once the composition has been stuffed into the paper tubes, they are placed on their sides and set aside on a tray to dry out in the open air. N/C lacquer releases acetone and other highly flammable solvents as it dries, and I don’t want these vapors collecting in my shop as this occurs.

Toward the end of the tube filling, the remaining strobe-putty started to dry out and became difficult to consolidate into the tube. I added just a touch of acetone to the composition to re-dampen it.

It took 3 or 4 days for these pots to dry completely. When I tried to burn them before they were completely dry, they did not burn with a regular strobing-action, but with a more continuous flame.

Priming the strobes

The dry pots will light well if they are ignited with a piece of Visco-fuse or with a propane torch. But if I want them to ignite reliably with a fast-fuse or quickmatch line of fuse, then I need to prime them.

A black powder prime containing potassium nitrate cannot be used on these compositions because of the incompatibilities between the nitrate and the ammonium perchlorate.

In FAST, Dr. Shimizu lists a different prime specifically for this use.

Ignition Composition for Twinklers

Chemical	Percentage	16-Ounces	450 Grams
Potassium perchlorate	0.74	11.85 ounces	333 grams
Red gum	0.12	1.9 ounces	54 grams
Charcoal, airfloat	0.06	0.95 ounce	27 grams
Potassium dichromate	0.05	0.8 ounce	22.5 grams
Aluminum*, flake 100-325	0.03	0.5 ounce	13.5 grams

*Skylighter #CH0174 aluminum would fit the bill in this prime.

After making sure all the individual chemicals (except the aluminum) will pass through a 100-mesh screen, I weighed them out individually and mixed them together by passing them through the 20-mesh screen three times.

I weighed out 1 ounce of the dry strobe prime composition, and added 1 ounce (by weight) of the nitrocellulose lacquer. This created a wet prime comp that had a consistency between that of honey and peanut butter.

I used a wood stick to apply this wet prime to one end of each strobe pot, and quickly pushed that wet end into some dry strobe composition for the final prime layer.

I perform one final operation to finish the individual strobe pots. I hot-glue a paper disc onto the bottom of each pot. This prevents sparks and/or slag from dropping and igniting the bottom of a twinkler prematurely as the pot burns. It also facilitates mounting the pots to a board when a show is being set up.

Mounting and fusing strobe pots for use in a fireworks display

Once the individual strobe pots have been completed, they can be mounted to a board and fused for easy installation out in the field prior to a fireworks show.

To do this, I simply hot-glue the pots to a board at the desired spacing. I find a spacing of 4 feet on-center to work well. Then a run of quickmatch or tape-covered fast-fuse
is used to fuse all the pots together. A “window” is opened up in the quickmatch-pipe, and the bared black-match is taped on top of the strobe pot with 3 wraps of masking tape.

The quickmatch can be ignited by a piece of Visco-fuse, or an electric igniter can be employed, per the information in How to Make Electric Matches and Wiring Fireworks and Firing Systems in a Fireworks Display.

Results

I burned white and pink strobes made with the 200-mesh magnalium. The white one burned for 15 seconds with a very fast strobe rate of about 10 flashes per second. The pink one actually looked red, burned for 23 seconds, and flashed about 4 times per second.

Warning: These strobe pots burn with an extremely brilliant flame and light. It is best to avoid looking directly at them to prevent eye damage. Placing the pots where their light can reflect off of a structure or trees makes their effect visible without having to look directly at them.

Click here to see a video of the white and red strobes.

I liked the performance of the pink/red strobe, but the white one flashed too rapidly for my taste.

So, I made a new batch of each color using 60-mesh magnalium. I know that using a larger granulation of the metal will slow down the burn time and also its strobe frequency.

Burning these new strobes produced the following results:

White strobe with 60-mesh magnalium, burned for 25 seconds, and flashed 1.5 times per second. I found this to be a very pleasing strobe frequency.

Red strobe with 60-mesh magnalium burned for 27 seconds, flashed at a rate that varied from slow to fast. This pot just couldn’t seem to find a groove and settle into it.

Check out the video of these two types of strobe pots:

Of the four variations I prefer the white strobe pots made with the 60-mesh magnalium, and the pink/red twinklers made with the 200-mesh magnalium.

Although I made mostly 1-inch long twinklers, I also made some larger ones. Two-inch long ones, made in the 3/4-inch ID tubes, burned as follows:

• 2-inch white strobe with 60-mesh magnalium burned for 40 seconds with about 2.5 flashes per second,
• 2-inch long red strobe with 200-mesh magnalium burned for 40 seconds with flashes varying from slow to fast again.

And, last but not least, I rigged up some white strobe pots using 60-mesh magnalium on a board and accompanied them with the music I linked to right at the beginning of this article. You can get the idea of what I had in mind in the first place as a nifty addition to a fireworks display. Click the video below of the three white strobe pots accompanying Who’s Won’t Get Fooled Again.

I do like what these simple, low-level ground devices can contribute to a fireworks show.

Enjoy,

Ned

Next Page »