Making a Firework Cake with a Star Gun

Two separate events have led me to explore this subject.

Harry emailed me and said that Skylighter had received a shipment of functional, but ugly, star testing guns. He said that he was willing to make folks a great deal on them if I could find a way to illustrate the need for them and how to put them to good use.

I said that I could easily do that, and that I had in mind a bonus, creative way to put them to use.

Additionally, a fellow pyro on Passfire.com was recently mentioning that he was having problems with some stars he had made. He related that he had ignited some of them while they were sitting on the ground, and although they had burnt all the way through, there was not much effect from them and they had left a large ash on the ground ounce they had gone out.

So, all of that came together, and this little article is the result.

Well, technically it’s not.

I’ve lit and thrown many stars to test-burn them in the air, and usually could do so without burning my fingers if I licked them first. Sometimes I’d grab the leather glove, but then sometimes I was too lazy for that move.

I have made Super Bottle-Rockets using Steve Majdali’s tooling, available in the ads in the back of the PGI Bulletin. Taping a test-star atop one of these nifty little rockets is a great way to get the star way up in the air where it is ignited. But, making a rocket to test each star can become a bit too much work.

Way back when, I got the bright idea of getting a slingshot, taping a piece of visco fuse to a star, loading it all into the slingshot, firing up the visco, pulling back on the rubbers, waiting until the star just ignited, and letting ‘er fly. I just knew I’d invented a new useful pyro device. Even called it my “Kentucky star gun.”

I posted my “unique” invention on a pyro discussion list, and a well known fireworker responded that he’d been doing just that for years, and that he had some good welder’s gloves (which covered the arm in addition to the hand), which he could sell me, and which were handy for that operation.

Darn. I’d reinvented the wheel once again. That happens a lot in hobbyist fireworking.

But, with all these devices, the idea is to test-burn a star or comet flying through the air at some distance from us.

Often color stars don’t show their true colors if we are too close to them while they are burning. They’ll look quite different at a distance of 100 feet. And they burn differently when flying through the air than they do sitting still.

For instance, willow stars and glitter stars won’t create their unique effects at all if they are just sitting on the ground burning. But put them up flying through the air, and we can begin to appreciate their effects and visualize what hundreds of them flying out of a shell-burst will look like.

And, honestly, a slingshot or hand-tossing will not get the star very far from me nor very high in the air. They will often burn me. If half of my attention is on not getting burnt. I won’t really focus on noticing how the star performs.

Enter the tried and true star gun.

My star gun has 5 tubes on it: 3/8-inch, 1/2-inch, 5/8-inch, 7/8-inch, and 1 1/8-inch inside diameters.

Using FFg or FFFg sporting grade black powder, I use lift powder loads as follows:

3/8-inch	Shallow 1/8 teaspoonful
1/2-inch	Flat 1/8 teaspoonful
5/8-inch	Heaping 1/8 teaspoonful
7/8-inch	Flat 1/4 teaspoonful
1 1/8-inch	Heaping 1/4 teaspoonful

To test a star, I determine which of the tubes will be a close fit for the star, while still allowing it to freely fall to the bottom of the tube. Occasionally it is necessary to persuade the star to get to the tube bottom with a thin wood dowel.

I insert 3 or 4 inches of Visco fuse into the tube’s fuse hole, drop the correct amount of lift powder into the tube through a funnel, and insert the star.

Fire up the Visco, retreat, and prepare to observe the test star in flight.

Heck, single one-inch comets fired out of the large tube can be a little show all in themselves if it’s a night when I simply must “smell the smoke” from something.

OK, that’s using a star gun for what God intended it to be used for, but now let’s get creative.

I got to thinking that a star gun could be used to create a small 5 shot repeater cake device, progressing from the smaller tubes up to the largest of them, and making an increasingly impressive little display in the process.

Stars in ever-increasing sizes could easily be rigged up to create such a cake.

But I have a complete assortment of Skylighter special effects fuses: falling leaves and flying fish in various effects and colors. Why not play with these a bit to see what would make the most fun and impressive little show?

I’ll test these fuses one at a time to see which of them I like best, and which light best when shot, unprimed, out of the star gun.

First I insert the 4-inch piece of Visco fuse, and then dump the correct amount of black powder into the tube. Then I tip the star gun over, keeping the mouths of the tubes slightly higher than their fused ends.

I’m thinking that about 3 seconds of burn time for the special-effects fuse will be a good display duration. The burn time is shown on the Skylighter label for each fuse. In this case I’m testing red-crackling flying-fish fuse, which burns at about 1.9 seconds per inch, so I mark the bundle of fuse at 1.5 inches with a Sharpie.

Then I cut the flying-fish fuse with my anvil-cutters, and push the fuse into the tube with a wooden dowel.

With this particular fuse, ignition was very good as all the fuse lit when it came out of the star gun. The display was very nice, and the fuse burned out just before it came back down to the ground.

Warning: I do not reload the star gun in my pyro shop or anywhere else where I am around pyrotechnic devices. The star gun may still have a glowing ember in it and I don’t want flaming black powder to be ejected from it, along with a star or fish-fuse inside my shop. I treat the star gun as if it could go off at any time once it has been fired once.

The rest of the special effects fuses worked as follows:

The falling leaves fuses really don’t work well in this little device. They burn too long and come back to the ground before creating their signature effect.

All of the flying fish fuses worked well, but one-inch lengths worked better than the one-and-a-half inch pieces. The shorter lengths ensured that they burnt in the air rather than on the ground.

The first thing I did was plan a route that the fuse would take. Then I drilled the bottoms of the star-gun tubes to allow the fuse to pass through them on that route. The center tube fuse-hole was left as-is.

The first time I constructed the repeating cake, I used fast-visco fuse as shown in the photo below.

This configuration burned a little too quickly for my tastes, and there was not much delay between the last two shots because of the short length of fuse in that section.

So, I constructed the cake again using Chinese Visco fuse, as shown here.

This configuration burned much more to my liking, and the extra fuse between the final two shots lengthened the delay between them.

Stay Green and Have Fun!
Ned

Colored Gerbs

In Making Gerbs (Firework Fountains)I described a method for making homemade fountains, called gerbs, including how to make the tools for ramming them. In Using Homemade Gerbs Creatively I explored a few creative devices using fountains.

I was ready to move on from gerbs, but then I received a note from Paul N, a loyal Skylighter customer. In his letter, he began by referring to his homemade waterfall, in which he used consumer fountains, a trick I described in Consumer Fireworks Display: Firework Waterfall, Firecracker and Star Set Pieces.

In part, Paul said:

I of course did not relay this message to Harry, lest he get an even bigger head about the service he provides to us pyro fanatics. I could sure relate to Paul’s enthusiasm and inspiration. How often I have felt that same way.

I have never seen colored consumer fountains at local shops that might be used in the way that Paul envisions.

I like to use colored fountains as one of the stages in devices like wheels and girandolas (horizontal flying wheels). Just recently I was giving some more thought to homemade colored gerbs, and had dug out a past PGI Bulletin article by John Glasswick, entitled Gerb Colours.

John is a friend of mine and a master pyro craftsman, his gerbs and wheels are something to see. We see one another just once a year at the PGI conventions, and we have often competed against each other with our wheels or ground displays. It has been no disgrace to have him beat me in a competition, and it’s been a real honor the few times I’ve edged him out in points.

John hails from Canada, and spells words funny, like colour and splendour, but we won’t hold that against him. He graciously allowed me to use the information in his article as the foundation for this one. In that essay, John relates that he got many favorable (favourable) comments about the colors of his gerbs one year at the convention, along with quite a few requests for his formulae.

John started with a favorite red formula that had been shared by Tom DeWille on the Pyrotechnic Mailing List several years back. This red formula was slightly modified to create the other colors, with one exception; blue.

The blue composition came from Joel Baechle’s Pyrocolor Harmony, to which John added 15 parts titanium for sparks. About that book, John states, “I found Joel’s book well worth purchasing, and the book has also been invaluable for me for star colour formulas.”

Note: There is another nifty blue gerb formula and method described by Mr. Gilliam in the Fireworks Tips #52 article, Blue Steel Gerbe.

So, rather than quickly moving on from the subject of gerbs, why don’t we spend one more week on them, and explore color gerbs.

The following are the formulae from John’s article, as well as Joel Baechle’s blue composition, to these formulae John added 13% titanium. I use either fine spherical titanium such as CH3010, which produces a short, dense spray of fine sparks, or the coarse spherical Ti such as CH3001, which produces a long spray of larger silver sparks.

If you want a simple colored flame with no silver sparks, the titanium may be omitted completely. It could also be replaced with ferro-titanium if less brilliant, yellow-silver sparks are desired, or even coarse charcoal for a softer, orange spark spray.

Blue Gerb Composition	Ratio	16-Ounce Batch
Ammonium perchlorate, 200 micron	0.38	6.10 ounces
Black copper oxide, or red	0.16	2.50 ounces
Titanium	0.13	2.10 ounces
Parlon	0.12	1.90 ounces
Aluminum, 325 mesh fine flake	0.10	1.60 ounces
Hexamine	0.08	1.30 ounces
Airfloat charcoal	0.03	0.50 ounces
Total	1.00	16 ounces

Red Gerb Composition	Ratio	16-Ounce Batch
Strontium nitrate	0.44	7.05 ounces
Parlon	0.17	2.70 ounces
Magnalium, 200 mesh	0.17	2.70 ounces
Titanium	0.13	2.10 ounces
Red gum	0.09	1.45 ounces
Total	1.00	16 ounces

Green Gerb Composition
Same as above except substitute barium nitrate for the strontium nitrate.

Note: I ended up using only these three basic color compositions. Other colors were made by combining these comps in various ratios as described later on.

I will include John’s other formulae, though, as listed below:

Lime Gerb Composition
Same as green except use 0.43 barium nitrate, and 0.01 sodium nitrate.

Yellow Gerb Composition	Ratio
Barium nitrate	0.26
Sodium nitrate	0.18
Parlon	0.17
Magnalium, 200 mesh	0.17
Titanium	0.13
Red gum	0.09

Orange Gerb Composition	Ratio
Strontium nitrate	0.29
Parlon	0.17
Magnalium, 200 mesh	0.17
Sodium nitrate	0.15
Titanium	0.13
Red gum	0.09

Purple Gerb Composition	Ratio
Potassium perchlorate	0.20
Strontium nitrate	0.20
Parlon	0.16
Magnalium, 200 mesh	0.16
Titanium	0.12
Black copper oxide, or red	0.08
Red gum	0.08

Turquoise Gerb Composition	Ratio
Barium nitrate	0.36
Black copper oxide, or red	0.18
Parlon	0.14
Magnalium, 200 mesh	0.14
Titanium	0.11
Red gum	0.07

Some notes concerning these formulae:

• Strontium nitrate and sodium nitrate are hygroscopic, which means they will readily absorb moisture from the air. They should be stored in tightly sealed containers, and dessicant packs stored with them will help keep the chemicals dry. It can be helpful to dry the chemicals prior to using them, by spreading some of the chemical out on a kraft-paper-lined cooking sheet and heating it in a 200-degree oven for 2 hours.

  Warning: I repeat, this oven-drying is only done with these individual chemicals, never mixtures.

  Once gerbs are made using either of these chemicals, they should be burned in short order or they should be stored in tightly sealed containers (ziplock baggies work well) with some dessicant packs.

• Barium compounds are toxic, and simple precautions such as wearing gloves and a respirator will prevent them from being absorbed through the skin or lungs. Some folks are very sensitive to barium, and I’ve heard tales of those who have suffered its poisoning. It does not sound like fun.

• Some folks substitute saran for parlon with good results.

There is an article, Lancework – Pictures in Fire, by the Kosankes, in Pyrotechnica XV, which contains formulae for lance. The authors begin with red, green, and blue compositions and then combine those three powders in the following ratios to create other colors:

Yellow – 0.25 red, 0.75 green

Orange – 0.60 red, 0.40 green

Chartreuse – 0.14 red, 0.86 green

White – 0.14 red, 0.28 blue, 0.58 green

Purple – 0.60 red, 0.40 blue

Aqua – 0.25 blue, 0.75 green

Similarly, the Veline color star formulation system, found in Tom Peregrin’s Introductory Practical Pyrotechnics, starts with four basic color compositions, red, green, blue and orange, and mixes them to obtain other colors:

Yellow – 0.45 orange, 0.55 green

Chartreuse – 0.20 orange, 0.80 green

Aqua – 0.20 blue, 0.80 green

Maroon – 0.85 red, 0.15 blue

Salmon – 0.25 red, 0.60 orange, 0.15 blue

Purple – 0.15 red, 0.05 orange, 0.80 blue

I’ve always found it interesting that these basic color comps are not combined in the same combinations that paints would be. They are rather mixed so that the light they emit combines to give the appearance of a completely different color. I used these color-combining methods to achieve the other various colors of gerbs using the basic color compositions: red, green, and blue.

In his article, John states, “I have found the compositions difficult to ignite, but I have had no problems as long as they are primed with a 50:50 mix of black powder/gerb composition.”

In the Making Gerbs article, I described a Starting Fuel composition. I rammed one increment of this fuel before introducing any standard fuel, especially in gerbs where I was going to be drilling the nozzle aperture with a twist-drill. This prevents sparks during that drilling.

This Starting Fuel is perfect for priming the gerbs as John describes. The first rammed increment above the nozzle will be Starting Fuel. The second increment will be 50:50 Starting-Fuel/gerb-composition. Then increments of the colored gerb composition will be rammed.

This is called “step priming”, and is a common practice, especially when rolling round stars, when a low-temperature composition is going to ignite a high-temperature one.

This will work well to ignite our color gerbs, with one big exception. No composition containing ammonium perchlorate may be in contact for any length of time with a composition containing potassium nitrate, such as the Starting Fuel or any other standard black powder composition.

This is because the combination of potassium nitrate and ammonium perchlorate forms extremely hygroscopic ammonium nitrate within a short amount of time. If you try that combination, you’ll soon end up with a soggy mess which will not burn.

You might try standard priming if you’re going to ram your blue fountain and take it right out and burn it.

But, with the blue gerb comp which contains ammonium perchlorate, or any color mixture which contains that composition, we have to have a different first-fire/priming mixture if the gerbs will be stored for any length of time.

First Fire Composition		8-Ounce Batch
Potassium perchlorate	0.60	4.8 ounces
Airfloat charcoal	0.25	2.0 ounces
Sulfur	0.15	1.2 ounces

This composition will be used to ignite the ammonium perchlorate containing gerbs in the same step-priming fashion described above.

For simplicity, it actually can be used to prime any of these color gerbs.

For this project, I want to make several of each type of gerb in the basic colors, and I want to try mixing the basic compositions to form the other colors. So, I want to mix up 16 ounces of each of the red, blue, and green formulae for starters.

I think I’ll make up those basic mixes without the titanium in them. I can then see what they look like with just the colors, and then I can add the Ti to the mix for individual gerbs to see how they look with that metal in them.

Many of you may know this, but there is a nifty way to remember the basic colors of the rainbow: Roy G. Biv: Famous pioneer in paint coloration. Well, maybe not.

Red, Orange, Yellow, Green, Blue, Indigo, Violet (Indigo is the bluish purple, and Violet is the reddish purple, and I usually just lump them together as purple when I think of the rainbow.) ROYGBIV

So, I want to make a rainbow of colored gerbs.

To make a 16 ounce batch of one of the formulae, I take the decimal ratio of each individual chemical, and multiply that decimal by the final batch size to arrive at the amount of that chemical to use. For example:

0.44 x 16 = 7.04 ounces of strontium nitrate

0.17 x 16 = 2.72 ounces of parlon

0.17 x 16 = 2.72 ounces of magnalium

0.13 x 16 = 2.08 ounces of titanium

0.09 x 16 = 1.44 ounces of red gum

Total = 16 ounces

(My little digital scale weighs to the nearest 0.05 ounce, so I round the above amounts to the nearest 0.05 ounce, to get 7.05, 2.7, 2.7, 2.1, and 1.45 ounces, respectively.)

I then add all the individual chemical amounts together to make sure that the total is about 16 ounces (may vary a bit due to number rounding). In this case the total comes to exactly 16 ounces.

After weighing the chemicals out individually, I screen them one at a time through a fine-mesh kitchen colander, into a bucket. I check the weight of the complete composition and make sure it is very close to the original total batch weight I wanted. This ensures that I didn’t miss a chemical, and that I weighed each one accurately.

Note: If, during the screening, I discover that any of the individual chemicals won’t pass the screen, I mill that single component in a small coffee grinder until it is very fine. I have a mill that is dedicated to fuels, and one that is used only on oxidizers. I never put metals into any of the grinders.

I put the lid on the bucket and shake it a bit, to thoroughly mix the contents. Then I gently screen the mix one more time through the colander to break up any remaining clumps of chemical.

I did not granulate these compositions. I did use rubber o-rings on my tooling drifts to keep the loose comp from fluffing out when the tooling was inserted into the tubes.

A few more tips from John Glasswick’s article will come in handy now.

He does not press his gerbs, but simply compacts the compositions with his body weight on the tooling. Since the nozzle clay really holds up best when it is solidly compacted, I decided to ram the nozzle as I usually do, with 12-16 rawhide mallet blows. I used bulkhead mix without any grog in it since I plan on hand-drilling the hole in the nozzles.

After the nozzle was rammed, I started with a flat half-tablespoonful of the starting fuel, and consolidated that increment with 8 light hits with the mallet. I followed the starter fuel with an increment that consisted of 1/2-teaspoonful of starter fuel mixed with 1/2-teaspoonful of gerb composition. I simply mixed these fuels in a paper cup with a gentle swirling motion before introducing the mix into the gerb tube.

Note: Since I’m ramming the blue composition which contains ammonium perchlorate, and I’m planning on mixing that comp with other colors to produce color-mixes, I actually just used the potassium perchlorate first-fire composition for the priming of all the gerbs I made for this project.

Then I rammed increments of gerb fuel and finished off with a clay bulkhead, just like any standard gerb. I rammed all of these increments with the same 8 gentle drops of the rawhide mallet.

Note: One of the reasons John does not pound on his compositions is that they contain sponge titanium which he uses. Rough metals like that can cause sparks when they are hand rammed with a mallet. I’m using smooth spherical titanium, and I consider this to be safer to hand ram, although I am using gentle hits when I do this with these formulae. It is best to do this outdoors with no large quantities of exposed compositions just in case any accident occurs.

John notes that he uses thicker walled tubes for these gerbs because they burn hot and can burn through the walls of thinner tubes. I used 1/4-inch wall tubes throughout these gerb projects.

And, finally, because these compositions have magnalium in them, among other ingredients, they produce dross or slag when they burn. This dross can tend to clog a narrow nozzle aperture, so the holes that we’ll drill in these nozzles will be on the large side. For these 3/4-inch ID tubes I’m going to drill 3/8-inch nozzle holes. 5/16-inch ones might work, too, and would produce a bit more thrust and a higher spray of sparks.

• Blue

  I rammed a gerb in a 7.5-inch tube using the blue composition, without any titanium in it. It ate up 1.9 ounces of the blue composition, and once the starting fuel increments burned, it produced a really nice blue flame about 10-inches long. The fountain burned for one minute.

  The same gerb, using 1.75 ounces of blue comp and 0.25 ounces of titanium, mixed in a paper cup prior to ramming, burned exactly the same except it also produced a nice 6-foot tall spray of bright silver sparks.

  

  Blue Gerb Without Titanium

  Note: I am not cropping these gerb photos so that you can see their relative brilliance by comparing how much of the surroundings light with each one.

• Red

  I rammed a red gerb in a 7.5-inch tube, without any titanium in it. It took 2 ounces of the composition to do this. After the first-fire increments burned, a brilliant 8-inch red flame spouted forth for 60 seconds. But, the tube sidewall did burn through for the last 10 seconds and a lot of the flame started spewing sideways out of that enlarging hole.

  The gold-glitter and silver-titanium gerbs I made a couple of weeks ago only burned for about 30 seconds, so I could settle for a 30 second burn with these color gerbs as well. To accomplish that, looking at the sketch of a gerb and noting that the actual fuel grain in the 7.5-inch tubes is a little over 5 inches long, I could start with half that fuel grain. This would result from ramming the gerbs the same way, but starting with a 5-inch tube.

  A red gerb in a 5-inch long tube, rammed with 1 ounce of composition, burned for exactly 30 seconds, with no tube sidewall burn-through. It’s hard to overstate the brilliance of these red gerbs. Man, they are fierce!

  My assistant in these comparisons was my granddaughter, Michelle, and the red gerb was her favorite by far.

  I added 0.15 ounce of titanium to 1 ounce of the red comp and rammed that in a 5-inch tube. That gerb burned identically to the one above, but with a 6-foot spray of silver sparks. Very nice.

  

  Red Gerb Without Titanium

• Green

  Since the green gerb composition simply replaces the red’s strontium nitrate with barium nitrate, I expect it to perform similarly to the red. (Famous last words.)

  So I’m going to try 1 ounce of the green comp in a 5-inch tube. (It actually only took 0.75 ounce of the comp.) This gerb burned with a brilliant green for exactly 30 seconds, with no tube burn-through.

  0.10 ounce of titanium added to the 0.75 ounces of green fuel produced the same effect, with the addition of the silver sparks.

  

  Green Gerb Without Titanium

• Yellow

  For starters, I thought I’d try something simple to produce a yellow gerb: a combination of the red and green comps I already had mixed up, in a 0.25/0.75 ratio, as the Kosankes recommend with their lance method.

  So I took 0.25 ounce of the red comp and 0.75 ounce of the green and mixed them together. That mixture got rammed into a 5-inch tube, and I had 0.10 ounce of the mixture left afterwards.

  That gerb burned with a brilliant yellow flame, similar in brilliance to the red and green gerbs. I did notice a bit of a green tint around the edges of the flame, so I tried one with 0.30 red and 0.70 green to see if I could balance it on the yellow a bit better.

  I did like the more pure yellow color of that mixture better.

  

  Yellow Gerb

• Orange

  Yellow worked, why not try the Kosanke proportion for orange: 0.60 red/0.40 green.

  A 5-inch tube, burned with a brilliant orange flame for 30 seconds. The color looks more like red in the photo and video, but the gerb definitely had a brilliant orange color to it.

  

  Orange Gerb

• Purple

  One more color to try out. I prefer a purple that leans toward the blue end of the spectrum: an indigo. So rather than try the Kosanke 60/40 red/blue, I thought I’d try something more along the Veline proportion: 0.20 red/0.80 blue.

  Oh, man, really nice 30 second purple fountain tending toward the blue end of the spectrum, just like I like it.

  

  Purple Gerb

5/16-Inch Nozzle Aperture

I decided to try out my standard gerb tooling which automatically forms a 5/16-inch hole in the nozzle, rather than hand-drilling a 3/8-inch hole in a solid nozzle. This should increase the pressure inside the tube during the burn, and also increase the possibility that the dross formed by the burning fuel will clog the nozzle as it burns.

I used a 5-inch tube, 0.75 ounce of the red fuel to which I added 0.10 ounce of 36 mesh charcoal. This gerb burned for 30 seconds with a flame that was similar to the gerbs with 3/8-inch nozzle holes. It did produce a nice, soft, 5-foot tall spray of orange sparks which did not detract from the brilliance of the red flame.

Note: One more time, remember to begin each gerb with an increment of the starter fuel, and then one of 50/50 starter fuel/gerb composition.

Well, I have ways to make each of the 6 colors of the rainbow in brilliantly burning 30-second gerbs: Red, Orange, Yellow, Green, Blue, and Purple.

These colors, and other possible combinations, all start with only 3 basic color compositions: Red, Blue, and Green. I really have to try Aqua, one of my favorite colors, and then there’s chartreuse. What color is chartreuse, anyway?

And, if I want to I can make a blue fountain that burns for 60 seconds. (I suspect it is the magnalium in the other mixes which burns so hot that tube burn-through begins at 45-50 seconds with them.)

I can add the titanium to the compositions for a tall spray of silver sparks, or the gerbs can be burned with only the brilliant colors illuminating everything around them.

These fountains will make great additions to wheels and girandolas, and in the back of my mind I can imagine them lined up on a frame, shooting their flames on an angle, and creating designs and letters with them.

So many projects, so little time.

Paul, I hope the red and blue gerb compositions fit the bill for the “idea” you have in mind for your next backyard-waterfall project. Michelle’s favorite color is the red, and mine is the blue with the gentle orange charcoal sparks.

Thanks to Tom DeWille, Joel Baechle, and John Glasswick for blazing a path which we can follow when creating these beautifully colored flames.

Stay Green, and red, orange, yellow, blue, and purple, too.

Ned

Using Homemade Gerbs Creatively

Last post, Making Gerbs (Firework Fountains), I made some homemade gerbs, also called fountains, using either a gold glitter composition or a silver titanium one. These fountains create nice effects, either fired one at a time, or in a “front” with the gerbs in a line, spaced 8-10 feet apart.

One of the things I really love about handmade gerbs is their versatility. In this article I will show you how to incorporate these fountains in some other creative devices:

• I’ll mount some gerbs on a frame to create a waterfall.
• I’m going to show how to make a very simple, beautiful, color-changing spark wheel.
• I’ll recreate the Chromatrope wheel that was described in Mortar Racks, Fusing Techniques, and a Firework Wheel, using homemade fountains to drive it.
• I’ll show how to make a simple set-piece in the shape of a star, using two different types of titanium in the silver formula.
• And a simple line rocket will be assembled.

I totaled up the number of the glitter gerbs and the titanium fountains I need for all the projects I have planned, and I rammed them as described in Making Gerbs (Fireworks Fountains).


I drilled 1/4-inch nozzle holes in all of them except the four titanium gerbs that I have planned for the sample waterfall. I made 3/8-inch apertures in those nozzles so that they spray the silver sparks out more gently.


Also, the glitter gerbs are going to be used in pairs with the titanium ones. The glitter gerbs will burn, and then they will passfire from their bulkhead ends to the nozzle end of the Ti ones. So, I’ve drilled 1/4-inch passfire holes through the bulkheads of the glitter fountains.


When they are going to be used individually, I fuse the gerbs with Visco as shown in the photo above. But when they will be used in devices such as the ones I have planned for this project, I fuse them differently.


I cut some 4-inch lengths of thin blackmatch from Quickmatch or Super-Fast Paper Fuse. This match is doubled and inserted into the nozzle holes of the gerbs.

I screen together, through a 40 mesh screen, a black powder prime composition, consisting of:

Component	Ounces
Potassium nitrate	1.5
Air float charcoal	0.3
Sulfur	0.2
Dextrin	0.1

In a paper cup, I add enough water to the prime powder to create a slurry with the consistency of jam. This slurry is put in a plastic baggie, the top of the baggie is twist-tied closed, and the excess plastic is cut off. I clip a very small corner off of the baggie, and pump the prime into the nozzle holes until they are full.


I finish this priming/fusing off with a dusting of fine black powder granules, and the prime is allowed to dry for a couple of days.

This combination of blackmatch and black powder prime ensures a very positive ignition when the flame from quickmatch fusing reaches the ends of the gerbs.


Now I install paper buckets on the fused ends of all the gerbs, and on the passfire ends of the glitter gerbs. These buckets consist of 4-inch by 9-inch pieces of 40-pound kraft paper glued and rolled onto the ends of the paper tubes, resulting in a double walled bucket.

Traditional fireworks waterfalls use thin-walled paper tubes filled with a potassium perchlorate and aluminum composition, and hung pointing downward. The waterfall I’ll be making with these silver titanium gerbs will be a little different than that.


I was watching a special on Niagara Falls the other day, and I noticed that the water projects horizontally off of the rock river-bed and then gradually arcs over and starts to fall vertically. I started to wonder if something like that could be done with these Ti gerbs.


So, as an experiment, I’m going to mount four Ti gerbs, with the 3/8-inch nozzle apertures, horizontally on a board, 12 inches apart. I’m interested in seeing what sort of effect that produces.


Note: In past articles I’ve shown how Super-Fast Paper Fuse or Fast Yellow Visco can be wrapped with aluminum foil duct tape to produce quickmatch if one does not have access to that fuse.

I was not completely thrilled with the effect this falls produced. Many of the silver sparks burned out flying horizontally before they started to fall vertically. Even with the 3/8-inch nozzle aperture the gerbs still had too much thrust.


The next day I decided to make one gerb without any nozzle at all. I just pressed silver-titanium comp into the tube, and burned it. I was happier with the unchoked tube and would use gerbs in that configuration in the future. The waterfall effect would have been better with 16-foot vertical supports instead of the 12-footers that I used this time.

For the wheel frame, I took a 4-foot piece of 1×2, and mounted a threaded tube through a hole in the center of it. I will later use a 1/4-inch lag bolt to mount the wheel to a vertical support post.



Then I drilled a pattern of holes in the ends of the 1×2, through which I’ll tie on the gerb drivers.

I use waxed string to tie the glitter gerbs to the outer end of the 1×2, nozzle end pointing out. Then the Ti gerb is tied on next to it facing in the same direction. These drivers end up staggered so that the glitter gerb’s sparks do not ignite the fusing of the Ti gerb.

A quickmatch passfire is tied into the passfire end of the glitter driver and over into the thrust end of the Ti one.


I tie the pair of gerbs together to further improve their stability. Additionally, I covered the string ties with aluminum foil duct-tape so that there would be no chance of the ties burning through when the passfire ignites.


Note: In the past, to attach drivers, I’ve used plastic zip-ties, or iron wire, which are both less susceptible to flame damage, but this time I wanted to use the string, which is simpler, less expensive, and lighter.



The completed wheel is now ready to mount to a support post. There is a wood block at the top of the post to space the wheel out and away from the support to keep the wheel from hitting it.

When I am attaching the quickmatch drop-leader to a device which is designed to move, such as a rocket, girandola, or wheel, I always install a “positive disconnect” section. A “positive disconnect” is simply a section in the quickmatch which is designed to burn through and fall away. This is done by exposing, and overlapping bare blackmatch from the ends of two pieces of quickmatch and wrapping with clear packing tape. I then tie the packing tape bucket to secure it in place.

This disconnect ensures that the plastic-and-paper match pipe and the blackmatch string actually detach from the device. I have had moving devices fail to move due to the incomplete detachment of the quickmatch leader. This is a bad thing.

Note: Mounting the drivers at a 45-degree angle to the 1×2, instead of at a 90-degree angle increases the final wheel display’s diameter. It also decreases the thrust that the drivers impart to the wheel, thereby slowing its rotation and making it appear more graceful.

Note: As I was constructing the wheel, I was constantly thinking through the ignition and burn sequences, and imagining all the possible things that could go wrong and could be avoided. The aluminum foil over the string ties was such a counter-measure. In even this small wheel there is a lot of time and effort and I’d really like it to work well. There’s a huge difference in the feeling I have when something works as designed, as opposed to disappointment I feel when it crashes and burns.

I also remade the Chromatrope wheel, this time with homemade gerb-drivers. The ends of the arms on the two spark wheels will have pairs of gerbs mounted on them in exactly the same manner as the simple wheel above. One wheel will rotate clockwise, and the other will move counterclockwise.

Homemade fountains can be arranged in a multitude of ways to create a set-piece, forming letters, a word, or any other design.


I decided to create a simple, 5-fountain, star set-piece to illustrate what can be done with these gerbs.

I used 12-foot 1×4’s to make the framework, and mounted the gerbs with zip-ties and a shim under the nozzle end to slightly point the exhaust out away from the frame. The shim is simply a section of a 1.25-inch ID paper tube.

For this little project I made 5 gerbs with the coarse spherical titanium (CH3001) and 5 with the fine spherical Ti (CH3010). The two effects were dramatically different.

The star on the left, using the coarse Ti, could have easily been made twice as large, and the one on the right with the fine Ti could have been made slightly smaller.

With one last little bit of creativity, I assembled a couple of line rockets. The first one had one driver (this type of rocket makes a nice effect flying into a bonfire as the fire is lit). The second one had two drivers in opposite directions, one burned then passed fire to the other, produced a back-and-forth flight.


In both cases, the gerbs were taped to a piece of PVC plumbing pipe which has the same OD as the fountain tubes.


The pipe is installed on a length of iron wire as the wire is strung tightly between two solid supports, like trees.

In this case, in order to develop enough thrust with the Ti gerbs, I drilled the nozzles with a 3/16-inch drill.

In his book, Introductory Practical Pyrotechnics, Tom Perigrin has some fun ideas for other creative variations on the line-rocket theme. Rat Packs, Jeweled Rats, Pigeons: So many experiments, so little time.

So there you have it. Plenty of ideas on ways to put simple homemade gerbs to use. They don’t make much noise, they are relatively safe, their effects last a long time, they make for instant gratification, and they offer endless opportunities for creativity.

Have fun and stay safe,

Ned

Making Gerbs (Firework Fountains)

After talking for the past few weeks about all the interesting things we can do with commercially-made consumer fireworks, let’s now make some simple, easy-to-make display items of our own.

In a past article I wrote about making nozzles and bulkheads. We’ll be putting those lessons to work in this article.

In Making Your Own Firework Tubes I explored cutting, treating, and rolling paper fireworks tubes. These tubes will also be used in this project.

Homemade fountains, called gerbs by pyro-folks-in-the-know, are very versatile devices. They can be used as stand-alone fountains shooting sprays of sparks skyward, as drivers on wheels, as downward spraying tubes in a homemade waterfall, or as line rockets.

I’ll be demonstrating those line rockets, sometimes called rats or pigeons, in the post following this one, so stay tuned. I’ll also be using these fountains as drivers on a fireworks wheel. I described using commercial cone-fountains to drive one of these unique Chromatrope double-wheels in Mortar Racks, Fusing Techniques, and a Firework Wheel.

Devices very similar to these fountains, employing a slightly faster-burning fuel and a somewhat different nozzle configuration, were what I described in the How to Make End-Burner Rocket Motors. In that article I showed how gerbs can be used to create a design, called a gerb set-piece.

From Wikipedia: A gerb is a type of firework which produces a jet of sparks, usually from 15 to 60 seconds. It is a thick-walled tube filled with pyrotechnic composition and possessing a choke, which is a narrowing in the tube. Gerbs are often referred to as “fountains.”

I don’t know what the origin of the word “gerb” is, but I learned, while trying to find out, that there is a Star Wars race of the same name. Interesting.

The word is pronounced the same as “germ” but with a “b” instead of the “m.” I wouldn’t want to saunter up to a group of pyros, trying to appear experienced in the ways of fireworks, and say “gerb” as in “Gerber” baby food, now would I?

Gerbs are one of the most simple of fireworks, but they offer the opportunity to learn some basic fireworking skills, and also to get in the habit of practicing basic safety precautions.

I’ll be using a 1/4-inch wall, 3/4-inch ID, 7-1/2-inch long, paper fireworks tube in this project: Skylighter tube #TU1068, or cut from #TU1065.

This size tube, 3/4-inch ID, and the rockets and gerbs that are made with it, are traditionally referred to as “one-pound” tubes and devices.

I have treated the tubes with Minwax Wood Hardener, and have allowed them to dry completely.

I have made some clay nozzle mix, and also some bulkhead mix, as described in a previous article.

In the Skylighter Project Plans
article, How to Make Saxon Fireworks Wheels by John Werner, two fuel formulae are included. I have used these compositions for saxons, stars, and gerbs, and they are among my favorites.

I have slightly modified the two formulae so that they use only readily available chemicals.

Component	Ratio	72-Ounce Batch
Potassium Nitrate	0.49	35.3 ounces
Airfloat Charcoal	0.12	8.65 ounces
Sulfur	0.06	4.3 ounces
Sodium Oxalate	0.08	5.75 ounces
Antimony Trisulfide	0.15	10.8 ounces
200 mesh Magnalium	0.10	7.2 ounces

(For the Antimony Trisulfide, either Chinese Needle or Dark Pyro may be used.)

Component	Ratio	72-Ounce Batch
Potassium Nitrate	0.51	36.7 ounces
Sulfur	0.10	7.2 ounces
Airfloat Charcoal	0.09	6.5 ounces
Spherical Titanium	0.30	21.6 ounces

(For the Titanium, either the fine (CH3010) or the coarse (CH3001) metal may be used. Each one will produce its own unique effect. The fine will produce a short, dense spray of small sparks. The coarse will produce a longer spray of fewer, large sparks. In this project I am using the coarse titanium.)

Each gerb will use about 3 ounces of fuel, and I plan on making about 24 of each type of gerb for use in these projects. So I am going to make 72 ounces of each formula.

To make smaller batches, simply multiply the ratio amount of each component by your final batch size to determine how much of each chemical to use. For example, if I want to make a 12-ounce batch of the gold glitter comp, I determine how much potassium nitrate to use by multiplying 0.49 x 12 and get 5.88 ounces (which I’ll round off to 5.9 ounces).

The two fuels above will be all I need if I am using tooling which forms the nozzle aperture as I ram the gerb. But, if I am using tooling which forms a solid nozzle in which I then make a hole with a twist-drill for the aperture, I want to ram a first increment of fuel which has no metal included in it. This eliminates the possibility of creating sparks with the drill.

I only need a small batch of this starting fuel because I’ll only be using one increment of it in each gerb.

Component	Ratio	8-Ounce Batch
Potassium Nitrate	0.73	5.85 ounces
Sulfur	0.14	1.10 ounces
Airfloat Charcoal	0.13	1.05 ounces

After weighing out the individual chemicals for one of the fuels, I screen the potassium nitrate, sulfur, and charcoal together through a 40-mesh screen, four times. I never put any chemicals like the antimony sulfide, magnalium, or titanium through my good screens because the metals will clog the holes in my screens, and future compositions that get screened could end up with some of the metals in them.

Then I put the screened composition into a bucket for which I have a lid. I screen the remaining chemicals through a fine-mesh-screen kitchen colander, allowing them to fall into the bucket, too.

Then I put the lid on the bucket and shake it for awhile to thoroughly mix the ingredients.

I add enough denatured alcohol (available in the paint department of stores like Home Depot) to form a workable putty with the consistency of bread dough. The glitter batch required 20 ounces of the alcohol by weight. The titanium batch required 16 ounces, and the starting fuel batch took 2.4 ounces. No water is used when making these dampened compositions.

The putty is then screened through a 1/4-inch mesh screen onto a kraft paper lined tray. I’ve made a framed screen which fits nicely into some kraft-paper-lined metal cookie sheets.

After granulating the putty through the screen, I spread the granules out evenly with a coarse-toothed comb and allow them to dry thoroughly.

Note: This alcohol-granulation step greatly reduces the dust that gets produced during the following ramming operation. It produces soft, relatively dust-free granules which will crush easily during the ramming to form a densely consolidated fuel grain.

Skylighter sells one-pound gerb tooling, #TL1110. I have a set of gerb tools that is very similar to that one.

Note: You can see the rubber o-rings that I keep on my rammers. These keep dust from easily fluffing out of the tube as the rammer is inserted.

It is possible to make your own gerb tooling. I start out with two, 4-inch diameter discs cut out of 3/4-inch plywood (or these can be square). I also cut some lengths out of a piece of 3/4-inch diameter oak wooden dowel.

I started by drilling a 3/4-inch hole, 1/2-inch deep into one of the plywood discs. Then, using the same centering hole, I drilled a 1-1/4-inch wide, 1/4-inch deep, recess in the disc.

The two plywood discs are glued together, and a 3/4-inch piece of the dowel is glued into the hole of that same size. This assembly is allowed to thoroughly dry.

I’ve cut two 9-inch lengths of the dowel to make the rammers. I leave the one rammer flat-ended, with the ends sanded smooth. I bevel the end of the other rammer at a 45-degree angle except for the center 1/4 inch, using my belt sander.

The convergent angle that is formed on the top of the nozzle by this beveled former helps direct the hot gasses out of the aperture and reduces burn-through of the tube side-wall.

I use aluminum foil duct-tape to cover the flat top of the base nipple and the end of the flat bottomed rammer so that they don’t stick to the clay or fuel as they are being rammed.

It is also possible to make longer-lasting rammers out of aluminum rod.

The only additional tools I’ll need for this project are a solid post on which to pound the gerbs, a rawhide mallet, a funnel, and some measuring spoons. I’ll also use a drill bit to hand-twist-drill the nozzle aperture.

I ram devices on a 6×6x36-inch piece of treated pine, which absorbs the shock nicely without bouncing.

A rawhide mallet transfers all of its force to the rammers, whereas a rubber hammer would bounce off and would not be nearly as effective.

The first step in the actual process of making gerbs is to place the paper tube onto the tooling base, and ram the nozzle clay. I place a mark on the nozzle end of the tube because once the completed gerb is rammed it will be difficult to tell the nozzle end from the bulkhead end.

As you can see in the sketch of the gerb, I want the actual throat of the nozzle to be about as high as the tube ID, or 3/4 inch in this case.

I mark my nozzle-forming rammer with a Sharpie at the point where the top of the tube will be when the rammer is inserted far enough to be sitting at the top of such a nozzle.

Then I experiment with introducing and pounding enough clay to form that 3/4-inch tall nozzle. In this case, 0.5 ounce (a flat tablespoonful) of the bulkhead clay created just the right nozzle thickness once it was rammed.

I used 16 moderate blows with the mallet to ram/consolidate the clay. A very slight bulge in the tube where the nozzle is pressed is good; you can see in the sketch that perfection is when you ram the nozzle and bulkhead so that they slightly bulge the tube wall. This locks them into place and helps them withstand the extreme gas pressures of the burning gerb. But obviously I don’t want to apply so much force that the tube is damaged or splits.

I’ve been pounding nails with a hammer just about all my life, so it comes naturally to me. It pays to take some time to practice swinging the mallet smoothly and with consistent blows, and it is an acquired skill which will pay off handsomely once it is mastered.

If I am forming a solid nozzle that I’ll have to drill into to form an aperture, I use the bulkhead clay mix which has no grog in it. Any grog in the mix would prevent me from being able to do such drilling.

If I am using tooling which forms the aperture (no drilling required), then I use nozzle mix which has the grog in it. This mix is less susceptible to erosion during the burning of the gerb.

Now I want to press my fuel grain in the paper tube on top of the formed nozzle. I place a mark on my flat-ended rammer where the top of the tube is when that rammer is inserted all the way to the top of the nozzle’s beveled edge. Then I put more marks on the rammer every 1/2 inch below that first mark.

The last mark is 1 inch from the lower end of the rammer. That marks the top of the last fuel increment.

I want to ram the fuel in half-inch increments so that they are very solidly consolidated. Very slightly rounded half-tablespoons-full of the fuel produces increments of that size in these tubes.

If this is a gerb in which I’m going to have to drill the nozzle aperture, then the first increment of rammed fuel is made with the starter mix which has no metal in it.

Note: I measure out about 3 ounces of the fuel into a paper cup, and this is the only exposed composition in my work area as I work. I keep the rest of my compositions in tightly capped containers. Minimizing this kind of exposure can save my life in case of an accident. I wear safety glasses while I work. I consider it to be safe to hand-ram the fuel with the spherical titanium in it, but I would not do so with a rougher, sponge-type titanium.

After that starter increment, I ram increments of the standard fuel until I reach the last mark, which leaves a 1-inch empty void in the tube. I use 8 moderate blows of the mallet to consolidate each increment of the fuel. Again, I try and repeat these blows with the same force each time in order to produce consistently burning gerbs. If I don’t, my gerbs will burn with differing degrees of power-sometimes producing a high spray, then dropping down lower. I want all my gerb’s to burn the same.

I now ram one increment of the bulkhead clay, which fills 1/2 inch of that void, and leaves the last 1/2 inch of the tube empty.

Note: One secret to really effective gerbs is to ram about 1/8 inch of black powder, similar to FFg sporting grade powder, in between the final fuel increment and the clay bulkhead. When the gerb burns to that point, the black powder burns almost instantaneously, producing a “bounce” which finishes the gerb off dramatically, leaving no doubt that it’s done.

The commercially made gerb tooling that I have automatically forms a 5/16-inch nozzle aperture. If I have pressed a solid nozzle with homemade tooling, I use a 5/16-inch drill bit, gently twisted into the nozzle by hand, to form the hole in the rammed nozzle clay. I let the drilled-out clay fall back into my tub of clay mix because it’s just fine to re-use it. I drill until the bit is just through the clay and into the starter fuel.

As you’ll see a bit later in this essay, it is also possible to use different size drill bits to vary the size of the nozzle hole. This also changes the thrust of the gerb, the height of the spray of sparks, and other aspects of the effect.

I then take some Chinese Visco fuse, double over about 1/2 inch of it, making a little “V” on one end of it, and insert that doubled end into the nozzle hole. I like the Chinese Visco, as opposed to the American, for lighting rockets and devices like these gerbs because it throws out a tremendous amount of sparks as it burns. As a result, it lights things very reliably.

The gerb is now ready to be stuck in the ground, taped to a stake, or inserted into a wood base with a drilled recess, ready for ignition.

These gerbs, made with either fuel, burn for 20-25 seconds. The glitter fuel produces a graceful, soft, golden spray of popping glitter globules. The titanium fuel produces a forceful, bright spray of silver sparks.

I have to say that even after almost 20 years making fireworks I still get excited when I make one of these devices, take it out into the field, and light the visco, waiting to see how it performs. I suppose it’s the one activity I’ve never lost interest in.

I won a PGI gerb competition a few years back with a pair of 1-1/2-inch ID gerbs. I carefully weighed out alternating increments of the glitter and titanium fuels, so that the pair burned with simultaneous pulses of the bright titanium sprays alternating with periods of the soft glitter plumes. Then I ended both gerbs with dramatic “bounces.” I was very pleased with the fountains and apparently so were the judges.

The final resulting pressure at which a gerb burns is determined by the power of the fuel and the size of the nozzle aperture. With a given fuel, the pressure and height of the spray can be adjusted by changing the size of the hole in the nozzle.

A large hole, or no nozzle at all, will result in a low pressure, short spray, and the fuel will burn relatively slowly. When these fountains are hung in a line, upside-down, to create a waterfall, this sort of slow, graceful, low pressure burning is desirable.

A smaller aperture will result in high pressure, tall spray, and faster burning of the fuel. Too small a hole will result in the strength of the nozzle or tube being exceeded, and the tube will violently rupture or the nozzle will be blown out of the tube.

So within certain limits the size of the drill used to make the nozzle aperture can be adjusted and the burn of the resulting gerb can be observed and noted.

This is all just part of the fun of making firework. In my playing around, I found that the glitter gerbs work very well with 1/4-inch to 5/16-inch nozzle apertures, burning for 25 seconds. With a 3/16-inch hole, the gerb burned 3-5 seconds faster with more thrust, and the glitter effect was almost completely lost.

The titanium gerb results were: 5/16-inch aperture – 20 second burn with about an 8-foot tall spray; 1/4-inch aperture – 20 second burn with a 10-12-foot tall spray; 3/16-inch aperture – 16 second burn with an impressive 16-foot tall spray.

Here’s a link to a video of a glitter gerb, a titanium gerb, and a pulsing gerb.

A 1/4-teaspoon “bounce” increment of FFg sporting black powder produced a very impressive final “thwump” at the end of the gerb’s burn.

Next time I’ll use these gerbs to drive wheels and line rockets. They can also be used, hanging upside-down, to create a waterfall/rain-shower effect.

‘Til then, stay green and have fun,

Ned

Cutting and Hardening Fireworks Tubes

In some upcoming posts, I’ll be discussing fountains (gerbs), wheel drivers, line rockets and black powder rockets.

These projects will require parallel wound paper fireworks tubes. To understand the difference between parallel and spiral wound fireworks tubes read the heading above the tube section on the Skylighter website.

There are lots of different diameter and length tubes listed in that section. Why would we need to know how to cut and treat those tubes?

If you look at product number TU1065, you’ll see a typical one-pound, 3/4-inch ID, 1/4-inch wall tube that is 30-inches long. Those tubes currently cost $54.59 for 25 of them, or $2.18 each. Four 7-1/2-inch tubes can be cut out of each of them, and each of those typical length rocket tubes would end up costing you $0.55 each.

Now, if you look at product number TU1068, you’ll see those same tubes, but 7-1/2-inches long, selling for $40.71 for 50 of them, or $0.81 each.

That’s a pretty big difference. If we know how to cut our own tubes out of the 30-inch long ones, we can save some money.

Additionally, some devices like short-duration fountains, stinger rockets, and other types of rockets require tubes of lengths that are different than 7-1/2 inches. Knowing how to accurately cut various lengths of tubes will be necessary when making those items.

Also, if these tubes are treated with a hardener, they will have a higher burst strength and will be more resistant to the flame burning through the tube side-wall while the device is functioning. So, it’s nice to know how to treat the tubes to accomplish this.

You might be saying, “Ned, why don’t you just use a hacksaw or coping saw to cut the tubes by eyeballing the crosscut?”

I have two main goals when cutting tubes: I want a very square cut which runs at exactly 90 degrees across the tube, and I want a straight, smooth cut.

I have used a, power miter, wood working saw to cut many tubes. This is a quick way to accomplish those goals. But it has some disadvantages. I don’t use such power tools in my fireworking shop, so to use that tool I have to go to the shop where it is located. It is also a bulky, heavy tool, which is not conducive to taking to pyro events where I might be cutting tubes and making various devices. Power tools are also dangerous, and can “grab” tubes when they are being cut unless one is very careful.

In the past year or so I’ve settled on a tube-cutting method which accomplishes my goals but which does not have the disadvantages I’ve listed above.

I found a plastic, Stanley, hand-sawing miter box at Home Depot, which has black plastic cams for locking a work-piece in place during sawing. Unless I’m just making one quick cut, I screw the miter box to my workbench to hold it securely in place during cuts.

I also found a nice, sharp, clean-cutting pull-saw at the same store. This saw cuts the tubes easily, quickly, and with very straight, smooth cuts.

Once the miter box is screwed down to my workbench, and the tube is locked in place with the cams, all it takes is smooth, gentle, pulling strokes on the saw to produce a nice, quick cut.

I like to cut about 1/4 inch off of the end of one of the long tubes so that I’m starting with a nice, square end, and then I’ll start measuring and cutting my tubes.

One of the really interesting things in pyro circles is how many different ways folks have to “skin the cat.” There are quite a few variations that folks employ to cut their tubes, and many of them work well. This is just one way that I’ve found which produces the kinds of results that I’m looking for.

For many devices, treating the tubes to increase burst strength and decrease side-wall burn-through is not necessary. For others, this process can really increase the performance of the tubes.

The most well-known product for treating paper tubes is Minwax Wood Hardener, available at Home Depot and other hardware and paint stores.

Warning: This stuff contains some pretty nasty ingredients. The solvent evaporates very quickly, putting highly toxic and flammable vapors into the air. Read the warning label, and only use it outdoors in a well ventilated area. Seriously!

I use two methods to soak the tubes in the wood hardener. If I’m only treating a few tubes, I’ll put them in a plastic, Ziploc freezer bag, and pour the hardener into the bag until the tubes are submerged. Then I’ll zip that bag closed while expelling most of the air. I’ll then put that closed bag into another one and zip it closed as well.

I like to soak the tubes for 15-30 minutes, and I’ll tumble the bag occasionally to make sure all of the tubes’ surfaces are being soaked.

Once the tubes have soaked for the allotted time, I’ll open the baggies and pour the excess hardener back into the cans using a funnel.

An alternative that I’ll use if I’m treating quite a few tubes is to put the tubes into a one-gallon paint can that is about half full of the hardener. I’ll insert as many tubes as I can, and then top the can off with the hardener. Occasionally I’ll pull the tubes out one at a time and rotate them so that both ends get evenly treated.

While the tubes are soaking, I cover the can with a plastic bag to minimize evaporation.

Then, with either method, I’ll remove the treated tubes and stand them on end on waxed paper to dry, once again in a well-ventilated outdoor area. The tubes can take 1-3 days to dry completely, depending on the climatic conditions.

The way I tell if they are completely dry is to put a few of them into a plastic bag and seal it. Then I’ll open the bag in an hour or so and see if I can smell any more of the evaporating hardener solvent. I’ll allow the tubes to dry until I can no longer smell it.

There is a nifty way to tell if the treatment is actually increasing the tubes’ burst strength. I’ll cut some 2-inch long sections of both treated and untreated tubes, and close off one end of each tube with masking tape.

Then I introduce 20 grams (0.7 ounce) of powdered clay, either bentonite or hawthorne-bond-fireclay, into the tubes.

Using a flat rammer, my rocket press, and a pressure gauge, I’ll slowly increase the pressure on the clay in the tube until the tube splits. I’ll make a note of the pressure at which the tube fails, and repeat the test several times to insure that the results are reliable.

Performing this test with treated and untreated one-pound, 3/4-inch ID, 1/4-inch wall, Skylighter firework tubes, I got the following results:

Untreated tubes failed at	4550 psi on the clay
Treated tubes failed at	5450 psi on the clay

That is an improvement of about 20% in the burst strength of the tubes.

Skylighter has also started to stock high-quality tubes in the 3/4-inch ID, 1/8-inch wall size.

I tested these tubes as well:

Untreated High Quality tubes failed at	6800 psi on the clay
Treated High Quality tubes failed at	6800 psi on the clay

“But can’t we make our own tubes?”

I have made some homemade tubes, with some success, but in the end I think it’s hard to beat store-bought ones.

If I had to roll my own though, I’d use one particular method that a well-known rocket expert, Terry McCreary, has popularized.

This method uses a metal former (mandrel) around which a release paper is wound, followed by rolled on layers of polyethylene-coated kraft paper. This paper is available at http://www.centralpack.com (in Protective Wraps) and a 24-inch by 600-foot roll of it currently costs $27.08 plus shipping. The paper is also available in 18, 36 and 48-inch widths.

This 600-foot long roll would make over one hundred and thirty 3/4-inch ID tubes, 1/8-inch wall, and 18 inches long. You can see that this results in some pretty inexpensive tubes, if you don’t count the cost of your labor.

For the mandrel which will form the tube, I purchased a 3/4-inch OD, 1/16-inch wall, steel tube, 36 inches long, at Home Depot in the nuts-and-bolts aisle. I cut the tube in half with a plumbing tubing cutter and filed the ends smooth. This produced two 18-inch formers. A hacksaw could also be used to cut the tube.

The release paper is parchment paper which is used for baking, and is available in grocery stores. I tear off a 20-inch long piece of it for each former and then I wrap the paper around the formers.

It is important to get the paper wound on the mandrels very tightly to eliminate any loose or weak spots in the final tube. It helps to roll the paper-wrapped-tube on a flat, hard surface, pressing down with the palms of your hands, until the paper is tightly wound onto it.

For each tube, I cut three 18-inch long pieces of poly-kraft paper off my 24-inch roll. I cut these using a large framing square and a razor knife to get very straight, square cuts.

Then I roll these three pieces on the tube former over the parchment paper, poly-coated side in, which results in a total of 72 inches of kraft paper rolled on. The resulting wall thickness is 1/8 inch, and the final tube OD is just a little over one inch. Once again I roll each piece of paper on very snugly.

The edge of the kraft paper is secured down with 3-inch lengths of 2-inch wide, clear packing tape.

Then the tubes are put in a 275 degree oven for an hour. This melts the polyethylene coating on the kraft paper and glues each lamination to the next one, resulting in a solidly glued-together tube.

The tubes are then removed from the oven and allowed to cool for several hours until they reach room temperature. The steel mandrels are then pushed out of the center of the tubes with a 1/2-inch diameter wood dowel, and the parchment paper is unwound and removed from the inside of the kraft tubes.

These 1/8-inch wall, handmade tubes were tested and have a burst strength of 4100 psi on the clay.

I have a simple, accurate method of cutting tubes to the lengths that I need.

Treating the standard tubes increases the burst strength by 20%.

Untreated high quality tubes have a 50% higher burst strength than untreated standard tubes.

Treating the high quality tubes does not increase burst strength in the tubes that I tested.

I have a method that I can use to make my own handmade tubes if I choose to.

There are some devices that would work fine with the untreated standard tubes, some that would work better with treated standard tubes, and others (like end-burning rocket and girandola motors) that will require the high quality tubes.

In forthcoming Fireworks Tips articles we’ll be playing with some of those devices.

Stay Green,

Ned

Consumer Fireworks Display: Firework Waterfall, Firecracker and Star Set Pieces

Mortar Racks, Fusing Techniques, and a Firework Wheel

In the last few weeks I’ve discussed making small Cremora fireballs and electric matches to use in a Consumer fireworks display, as well as firing systems and wiring techniques.

I’ve also covered many topics which deserve attention when planning the show and purchasing devices for it.

This week we’ll be looking at the construction of mortar racks from which to fire artillery shells during the show, how to construct a really nice wheel using fountains from the local fireworks store, and some techniques for using various fuses to attach devices together for the display.

Mortars are the tubes with plugged ends that fireworks shells, comets or mines are fired from. Mortars can be made of HDPE plastic, fiberglass, paper, or in some special cases, metal.

The mortars need to be secured in an upright and safe position. This can be done by burying the mortars (guns) about 2/3 of their length in the ground. Here are a couple of shots of some of the large guns that were buried for shows and competition at a recent Pyrotechnics Guild International convention.

Often, especially with smaller guns, the mortars can be securely held in place in racks, either perpendicularly or at an angle. The racks can be constructed of metal, wood, or a combination of the two.

Here are a couple of artillery shell racks made by Brian Paonessa at Skylighter, using Skylighter’s PL3182
fiberglass mortars. One is a fan rack, and the other holds the guns straight up and down.

Here is a shot showing some of the construction details of the fanned rack. Brian has glued and screwed the rack together.

Below is the angled PL3175 artillery shell mortar rack that Skylighter sells. The swing-out feet hold it in an upright position. When using this rack, I drill holes in the feet and drive spikes through them and into the ground to keep the rack from bouncing and falling over.

As you can see in the photo of the PGI racks above, wooden racks can also be held upright by attaching them together with lengths of wood 1×3s, or by pieces of plywood attached to both ends of them. In either case, screws or nails are used to keep the whole assembly upright and rigid.

Care must be taken to avoid driving fasteners into the mortars. In pyro this is known as a “bad-thing.”

Typically, except in the case of fan-racks, racks are set up so that their ends are perpendicular to the front of the crowd. That way, if a rack happened to come loose and fall down, it would not be firing toward the crowd.

Here is another way to secure wooden racks. Screw-eyes are installed into the rack ends, and rebar pins are used to hold the racks in place. Both ends of the racks are supported in this manner, and racks can be erected end-to-end with only one pin between them.

No matter what method is used to erect them, once the racks have been assembled, they ought to be secure enough to withstand a healthy kick with a boot.

In this section I’ll be referring to and using the various kinds of fuse shown in the photo below. Each one serves its own purpose and has its own unique burn-rate. The burn rate of a roll of any particular kind of fuse can vary. So it’s a good idea to cut 10 inches of the fuse off that roll and time it with a stopwatch as it burns to determine its exact burn rate.

American Visco	2.5 seconds per inch
Chinese Visco	1.7 seconds per inch
Fast Visco	0.25 seconds per inch
Fast Fuse	0.1 – 0.15 seconds per inch
Time Fuse	2.2 – 3 seconds per inch
Quickmatch	Instantaneous
Foil-Taped Fast Visco	Instantaneous
Foil-Taped Fast Fuse	Instantaneous

The foil-taped fast-Visco or fast-fuse may be used as excellent substitutes for quickmatch, which is not shippable. I described how to make it in Really Nice 4″ Plastic Ball Firework Shells .

In the rest of this article, I will refer to quickmatch, and you’ll know you can make substitutes for it with the fast-Visco or fast-fuse as described above.

So, I have filled 6 tubes in my rack with an artillery shell, comet, or a mine. If they are to be hand-fired, the shell-leaders (fuses) can simply be left hanging out of the guns, ready to be lit one at a time with a propane torch.

These shell leaders are fast-Visco fuse, and I’d expect a burn rate of about 4 inches per second, which will produce about a 3 second delay between lighting the fuse and the shell launch.

A shell of this size will take about 3-4 seconds to rise in the sky and display its starburst. So if I light the next fuse immediately after the first shell has launched, and so on, I’ll get a nicely paced series of bursts that lasts a total of 18-20 seconds.

If the shell fuse leaders are a bit on the short side and threaten to drop down into the mortars, they can be held in place with a little masking tape. Be sure the shells are all the way on the bottom of the guns, though, to insure proper height when they are launched. A shell that’s not seated solidly on the bottom of its mortar can become a “low break,” which, in turn, can cause fires or injuries.

But, let’s say I want all of these shells to launch at the same time at some point during the show or at the end of it (the “finale”). In that case I’ll chain them all together with a length of quickmatch. Chaining shells simply means attaching their fuse leaders together in a series. If the shells are chained together with quickmatch, and then the end of the quickmatch is lit using a piece of Visco fuse or an electric match, once the flame hits the quickmatch the shells will all ascend skyward in quick succession.

This is done as follows:

• Cut a length of quickmatch as long as the run of mortar tubes containing the shells, plus about a foot. Always use a razor blade or anvil cutters to cut fuse, never scissors.

• Pierce the quickmatch wall with an awl where each shell leader comes out of the top of the mortar, making sure that all the layers of match pipe are pierced and you can see the black match inside.

• Put a fresh diagonal cut on the end of the shell leaders with a razor blade in order to expose the powder inside the leader.
• Insert the shell leader into the quickmatch for an inch or so.
• Use masking tape or aluminum foil tape to secure the shell leader into the quickmatch. I really like the aluminum foil duct tape with the peel-off paper backing. The stuff sticks like crazy, will not gradually come loose over time, and is fireproof.

• Use string to tie the fuse chain down to the rack between each mortar. I like waxed string for this purpose. It makes “threading the needle” with it a breeze. This prevents the first shell from yanking the chain as it is launched, which might pull the rest of the leaders loose from the chain.

Warning: In the past, some folks have used a staple gun to staple quickmatch chains to the tops of wooden racks. More than once, the stapler has created a spark which has ignited the chain and instantly sent shells skyward. This has killed or seriously injured some people. Don’t use a staple gun to secure flammable fuse, nor use one anywhere near pyrotechnic compositions.

The nifty thing about this fusing method, and the following ones, is that they can be applied to fusing rockets set side-by-side in launch tubes, or to fusing cakes laid out in a field or on a piece of plywood. A whole show can be laid out, fused together with a combination of these methods, and fired by lighting one fuse or firing one electric match.

But Wait, There’s More! Maybe I want that nice 3-4 second delay between the shells’ firing that I spoke about earlier. Maybe I want a different delay time, but I want to fire the shells in a chain as in the section above. How can I build that delay in between each shell in the chain?

Near the end of the Pyrotechnica XI article, Traditional Cylinder Shell Construction, Part II, “Finale and Flight Chaining” is addressed. This is a fascinating explanation of “old-time” chaining methods using quickmatch, paper buckets (rolled tubes of kraft paper), string, spolettes and regular time fuse. It’s a valuable addition to my pyro library. In the photo above, there are about 3 inches between the center of each mortar. If I run one of the Visco fuses down the line instead of the quickmatch, and attach my shell leaders every 3 inches, then I will get 3 inches of delay between shots.

3 inches of the American Visco fuse will give me a delay of 7.5 seconds between shells. That’s more than I want, but that might work in some cases. 3 inches of the Chinese Visco will give a delay of 5.1 seconds between shots. That’s more like it. I could go with that, although it’s a bit more of a delay than I really want.

To use Visco for a chain, simply tape the end of each shell leader alongside the Visco fuse as it runs along the tops of the mortars. The two fuses must be parallel to and touching each other for at least an inch of tape. Then tie the chain down to the mortar rack as shown above. Don’t try to run the shell leaders into the Visco fuse chain at a right-angle. You’ll get poor or failed ignition that way.

There is another, more precise, way of incorporating delays into a chain of shell leaders, though. It incorporates sections of cross-matched time fuse, or the hand-rammed spolette fuses that I described in Firework Shells in 2-1/2 Days – Part 3.

The roll of 1/4 inch time fuse that I have burns at a rate of 2.2 seconds per inch. If I use 1-1/2 inches of it between each shell in the rack, I’ll get a 3.3 second delay between the firing of each shell. This is done as follows.

I want 1.5 inches of time fuse delay, and I’m going to split each end of the fuse 1/2 inch for cross-matching. So I cut five, 2-1/2 inch sections of the time fuse. I split each end 1/2 inch with my razor blade, insert three 2 inch pieces of the thin black match that can be found in the fast-fuse or quickmatch, and I tie each end of the time fuse closed with a clove hitch and overhand knot to secure each knot.

Then I make “buckets” out of 3-1/2 inch x 3-1/2 inch pieces of kraft paper, rolled around a 1/2 inch wood dowel, with the edge of the paper glued down. I then tie a bucket on each end of the cross-matched time-fuse pieces, with the knots just to the inside of the pieces of cross-match. Tie the knots very tightly so that hot gasses cannot escape the bucket and transfer over to the next one before the time fuse has burned through.

Now it’s just a matter of making a chain of these bucket time-delays, in similar fashion to the chains that were made above. The first bucket in the chain has a piece of quickmatch coming into it from the ignition source, and a piece of quickmatch coming out of it into which the first shell’s leader is tied or taped. I don’t want a delay before this first shell’s fuse is ignited. This first bucket also lights the first time-fuse delay element.

I bare the black match in the quickmatch for 3/4 inch before inserting it into the buckets. It’s easy enough to clip the buckets a bit shorter with scissors as necessary. It’s just important to avoid cutting into the cross-match with the scissors, and to leave enough bucket so that the knot can be tied without any blackmatch protruding beyond it.

During the chain assembly, it can help to tie each delay down to the rack before assembling the next link in the chain. This helps to insure that the quickmatch pieces leading to the shells are long enough, and are routed away from each other and away from the mouth of a previous mortar, which would lead to a premature ignition.

The chain shown above is designed to be ignited from the left end, to have 3.3 second delays between each shell, and to pass fire from the right end to the next device in the line if desired.

This same type of chaining using time fuse, can be used to link box-cakes to each other. Let’s say I start with the ignition of a cake that has a 30 second burn time, and I want to overlap the next box 5 seconds into the first cake’s time. I’ll put a 25 second delay time fuse and buckets at the ignition point of that second cake. On and on, this type of show can be assembled.

Now for the added bonus section in this article. I find it to be fun and creative to take consumer fireworks items from the fireworks store, and assemble them into larger and more impressive assemblies. Fireworks cone-fountains can be hung upside down in a line to form a waterfall, and they can also be used as drivers in this large wheel. “Drivers” provide the force to make the wheel go round.

Chromatropes are a traditional fireworks display exhibition pieces. They are simply composed of two counter-rotating wheels, each of which is a basic assembly of wooden crosses with the drivers attached at the ends of each arm. They produce the kind of effect shown below.

The device shown above has 8 pairs of crossing fountain-sprays, or 16 drivers. This would be 8 drivers per wheel, and with 1 driver at the end of each cross-member, each wheel would have 4 cross-members. We’ll build a simpler version, with two wheels, each having 2 cross-members and 4 cone-drivers.

Here is an illustration of a chromatrope out of Weingart’s Pyrotechnics.

You’ll notice in both the photo and the illustration that the drivers are mounted at a 45 degree angle to the arms, and will shoot their spray out at that angle. This angle also diminishes the amount of force with which each driver will drive the wheel. I’m going to mount the cone-drivers at less of an angle to increase their force when turning the wheels, since the cones are not as powerful as handmade drivers.

Here’s a very simple pictorial essay on this consumer fireworks model. The hubs that the bolt-axles go through are simply 3 inch long 3/8″ threaded tubes/nuts/washers, available at a hardware store in the lighting department.

I have cut 1-Inch x 2-Inch x 8 foot pieces of lumber in half to produce 4 foot long arms, and I’ve cut steep angles on the ends of each arm.

Then I drill 3/8 inch holes in the center of each arm, insert the threaded tubes, put some wood glue between the arms, and tighten the nuts and washers.

I’ve removed the wrapping paper from the cones and drilled some mounting holes in their hollow bases. I’ve also installed some extra scotch-tape to insure that the fuses are secured in their tops.

I then mount the cones to the arms with iron wire, and I install buckets and quickmatch to fuse them together. I have clipped the cone visco fuses on an angle to get fresh powder exposed, and I’ve glued and tied the buckets to the cones to insure that they don’t slip off.

I’ve assembled a T-support with 4×4 lumber and reinforcements. This insures that the wheels don’t hit the vertical support during operation.

I’ve assembled the wheels so that they are driven and turn in opposite directions. You’d be surprised how easy it is to mess this detail up.

On the day of the show, I’ll tie the two wheel ignition points into one leader so that both wheels will light at the same time.

I always test at least one of the wheels with the cones you want to use to make sure that they are powerful enough to get the wheels spinning once they are lit.

Stay Green,

Ned

Wiring Fireworks and Firing Systems in a Fireworks Display

In recent Fireworks Tips articles I’ve discussed making electric matches with which to ignite fireworks electrically, and the construction of Cremora fireballs which can be impressive additions to any show.

I’ve also looked at the issues involved in thoroughly planning a consumer fireworks display.

Now it’s time to discuss using those electric matches in conjunction with an electric firing system and shooting wire, and hooking fireworks devices up to them out in the field.

In the next article, I’ll also show you how to use visco fuse, fast-visco fuse, quickmatch, time fuse, and fast-fuse to attach fireworks devices to each other for sequential firing.

Using these methods together can result in a nicely timed display, and will also enable you, the display designer, to sit back and enjoy the show with the rest of the crowd.

“Scab wire” or shooting wire is the wire that is used to connect the firing panel to the electric match. It essentially extends the length of the leads of the electric match, or connects multiple igniters in one firing circuit. It is important to know the wire’s resistance for a known length of it.

Scab wire usually comes in rolls that have “duplex” wire on them, which means that the wire is two-conductor wire. Two insulated wires are attached to each other, side-by-side.

Two-conductor, copper, 22-gauge, yellow-insulation wire is probably the most commonly found scab wire out in the field. There is also copper-clad, aluminum, orange-insulation wire that is being imported and used.

I cut the wire with the wire-cutters (dykes), split the insulated wires apart with the same tool, or the razor knife, or with my fingernails, and strip the insulation with the dykes or with my fingernails. If I use the dykes to strip the insulation, I’m careful to avoid damaging the wire itself, which is easy to do. I therefore prefer to strip the insulation with my fingernails.

The most important thing to know about the wire that you are using is its resistance. This is listed as “ohms per 1000 feet” in wire data tables. It’s easy to determine this for yourself, though.

All you need is the wire and a multimeter, which measures voltage and resistance. A digital meter like the one on the left is a good investment because it will be used in this step and also in future testing of firing circuits. The analog meter on the right is good for testing batteries and can be used to check resistance, but it is not as accurate as the digital meter.

Note: In a circuit which contains electric matches, I only use the digital meter to check resistance. The analog meter can fire ematches, which is NOT something you want to happen!

To determine the resistance of my shooting wire, I take 50 feet of my duplex (two conductor) wire, bare 1 inch of both wires at one end of it, and twist those ends together securely. I then separate the wires at the other end for 3-4 inches, and bare 1 inch of those ends. Now I set the dial on the multimeter to the setting for measuring resistance (ohms) and wrap one bared end of the shooting wire on one of the meter’s probes, and the other end of the wire on the other probe.

I’m actually measuring the resistance in 100 feet of the single-strand wire since the measurement current is going out 50 feet to the twisted ends, and then back 50 feet to the meter.

I should get a reading between 1.6 ohms for the 22 gauge copper wire, and 3 ohms for the copper clad aluminum wire. This exact reading will depend on the actual wire you are using. I then multiply this reading by 10 to get the resistance in ohms per 1000 feet of the wire.

The yellow wire I’ve described has a resistance of 16 ohms per 1000 feet, and the orange wire’s resistance is about 30 ohms per 1000 feet.

I have a few different firing systems. I have a new Skylighter 12 cue wireless firing system (GN6020) which puts out 4.5 volts. Then there are my older model 8 and 12 cue wireless panels which put out 12 and 18 volts. I also have a hard-wired 144 cue firing system which sends out 24 volts, and I’ve recently seen the 10 cue capacitive discharge, hard-wired firing system (GN6011) at Skylighter which fires with higher voltages.

To determine the firing voltage of my firing systems, and to check the batteries in the panels before use, I simply set a multimeter on DC voltage, hook it up to one of the firing cues, and fire that cue. The meter will read the voltage that is being sent to that pair of connectors by the firing panel.

Before the show, I use the meter to check the batteries in my firing system, both in the transmitter and receiver. I always have spare batteries for the multimeter and for the firing system in my kit of spare stuff that I bring to a display.

This subject sounds like the simplest thing in the world, doesn’t it? But, believe me, there may be no quicker way to insure failure with a fireworks display than to ignore some of the “rules” of electric wiring that I’m about to relate.

If you keep these tips in mind electric firing can really be an incredible enhancement to any display.

• Attaching an electric match to the scab wire

Nope, I don’t need electrical tape, masking tape, or wire-nuts to do this. I start by separating the two wires at the end of the scab wire and at the end of the electric match. Then I strip 1 inch of insulation off of each of the 4 wires with my thumbnail.

The two pairs of wires are then tightly and completely twisted together.

An overhand knot is tied in each pair of wires.

The electric match wires and the scab wires are then pulled in opposing directions, the knots come together, and the twisted pairs of wires are wrapped around the main wires on opposite sides of the knots.

This results in ematch wires that are securely attached to the scab wires. The knots prevent the connections from being yanked apart in case someone trips over a wire. The wires wrapped in opposite directions prevent the two bare-wire connections from coming in contact with each other, which would prevent the electric match from firing when it is supposed to.

• Attaching shooting wire to the firing panel

Warning: When connecting electric matches to a firing system, have the system turned off and the safety key removed. Make sure all personnel are clear of the fireworks that are being wired up. If there are thunderstorms in the area, keep the wiring disconnected and the bare ends of the scab wire twisted together (shunted).

Once again there are right ways and wrong ways to attach wires to the firing system. First, I separate the insulated wires for about 3-4 inches, and strip the insulation back for 1 inch on each wire.

If I just stick the bare wires into the panel’s connectors, there’s a good possibility they can be pulled over and into contact with each other. This would short this circuit out and prevent the electric match from firing, as shown in the photo on the left below.

So, instead, I double each bare end against itself, insert those doubled ends halfway into the connectors, and then “pinch” the connectors toward each other to insure that the wires are really crimped into their connections.

You’ll notice that I’ve only inserted the doubled-ends into the connectors halfway so that I can visually insure that the connector is not clamping down on insulation instead of the wire. I have also not inserted the wires so far that the clipped ends of the wires are down inside the connector. This could make removal of the wires difficult at the end of the show, and possibly damage the connector.

• Strain-relieving the wiring at the firing panel and at the firework

So, on the day of the show, it’s getting late and dark, folks are becoming tired and are stumbling around, and there are lengths of shooting wire lying all over the shooting site, connecting the firing panel to the various fireworks.

At this point in the show setup, folks need to be reminded to walk carefully and avoid the wiring. And as soon as I do that, I’ll sure-as-shootin’ trip over a wire myself, yanking it loose from the panel, or worse, pulling way too hard on a fireworks cake fuse or a shell leader.

One simple procedure can prevent a lot of problems in the above scenario: strain relief.

Simply put, anchor your shooting wire and/or ematch leads to something solid near the fireworks and near the firing system. Often, the ematch leads can be tied off to a mortar-rack. But, if there is not something nearby to tie the wire to, I’ll simply drive a wooden or metal stake into the ground and tie the wiring to it with a clove hitch.

I place these wire-knots down the stake, near the ground so that if a wire is tripped over it won’t pull the stake over too far.

• Attaching the electric match to a fireworks device

Near the end of Making Electric Matches, I described one way to attach electric matches to the safety fuse on fireworks devices, using Fast-Fuse and masking tape. A length of quickmatch can also be used, as described in an article by Brian Paonessa.

I now know how to securely connect my wires to each other, to the fireworks devices, to the firing system, and how to safely strain-relieve them.

But, how much wire can I actually run between the firing system and the electric match?

Each electric match needs a minimum of 1 amp of electric current to run through it in order for it to fire. Because of the wire resistance which I described above, if too much wire is used between the panel and the electric match, less than 1 amp of current will flow in the circuit. We then run the risk of having the igniter fail to fire.

Ok, here it is: a formula. Don’t let it scare you off. I’ll actually help save you from having to use it in a moment.

Resistance = Voltage divided by Current

I know the minimum amount of current I want in a firing circuit: 1 amp.

I know the voltage that my firing system puts out: 4.5 volts (in this example, using Skylighter’s GN6020 firing system).

Resistance then equals 4.5 divided by 1 which equals 4.5 ohms. This amount of circuit resistance will allow a current of 1 amp to flow.

If I go above this maximum amount of resistance in my circuit, the current will drop below 1 amp. So, it’s fine if I have less than 4.5 ohms of resistance in the circuit since that will simply increase the current above 1 amp.

The homemade electric matches that I detailed in the article cited above all had a resistance of 1.2 ohms. Commercial electric matches will have typical resistances of 1.5 – 2 ohms. I’m going to assume we’re using the 1.2 ohm matches for the purposes of this discussion. (But you should always test yours.)

Since my electric match has a resistance of 1.2 ohms, and I want a maximum of 4.5 ohms of resistance in this particular circuit, then 4.5 – 1.2 = 3.3 ohms left over for the scab-wire’s resistance.

I can now calculate the maximum lengths of the wires that I can use. For example: the yellow scab wire has a resistance of 16 ohms per 1000 feet.

(Using the 3.3 ohms left for scab wire) 3.3 divided by that 16 equals 0.206.

0.206 times 1000 feet equals 206 feet.

206 feet of this wire would have a resistance of 3.3 ohms. This is the maximum amount of this wire I can have in this circuit. Any more of this wire and my total resistance will be too high.

But, this is a maximum of 206 feet of the single strand wire, and my shooting wire has two strands: one out from the panel to the ematch, and one back from the match to the panel. So, in reality, I can only have a maximum of 103 feet of the double-strand shooting wire between my 4.5 volt firing panel and my igniter.

If I am using the orange (copper-clad aluminum) wire described above, which has a higher resistance of 30 ohms per 1000 feet, then I could only use 110 feet of the single strand wire going out and back, or 55 feet of the double strand shooting wire.

The table below lists these figures for the two types of scab wire, the length of double strand wire between the panel and igniter, and for 4.5 volt, 12 volt, and 24 volt systems.

Max Resistance	Max ft. of yellow wire	Max ft. of orange wire
4.5 Volt Firing System (one igniter in circuit)
4.5 ohms	103 ft.	55 ft.
12 Volt Firing System (one igniter in circuit)
12 ohms	338 ft.	180 ft.
24 Volt Firing System (one igniter in circuit)
24 ohms	712 ft.	380 ft.

Once again, these are the maximum lengths of the double strand wire I can use in the circuit.

Now, it’s easy to run a maximum of 103 feet of the yellow, two-strand wire, hook up one end to the electric match, and the other end to my digital meter, and check the resistance in that firing circuit. The resistance should not exceed 4.5 ohms, and should fire successfully with my 4.5 volt firing system.

The test circuit shown below, with 100 feet of the scab wire, read 4.5 ohms and fired as designed.

This introduces the last bit of complexity into the subject of electric firing. Each firing cue can indeed fire more than one electric match, but as usual we have to be careful when designing the circuit so that our igniters will fire as planned.

There are two basic ways to hook up multiple electric matches to one set of connectors on our firing panel: in series and in parallel.

• Series Wiring

Series wiring has the electric matches hooked up one-to-another, so that the current flows through the complete line of igniters, one after another.

A significant advantage to series wiring is that, since the current has to flow through all the electric matches before it returns to the panel, the test lights on the panel will test all of the igniters at the same time. If there is a bad match, the test light will not go on.

Also, with a typical amount of shooting wire in such a circuit, series wiring requires less current to fire the igniters, thereby allowing longer lengths of the scab wire to be used reliably.

In the field, most pyros use series wiring, with few exceptions. Serial wiring is counter-intuitive to some people. They assume that if 2 or more electric matches are serially wired to each other, that when the first match fires, that first electric match will break the circuit and prevent the remaining electric matches in the circuit from firing. But in practice, the current flows so quickly that all the electric matches in any given serial circuit will fire at the same time.

In this series circuit, the resistances of the electric matches are added together to obtain their total resistance: 1.2 ohms plus 1.2 ohms equals 2.4 ohms of resistance for two matches.

We still only need one amp of current in the circuit, though, to fire the matches. So, using the 4.5 volt system, with my maximum resistance in the circuit being 4.5 ohms as determined in the example above, the maximum resistance of my shooting wire can be up to 2.1 ohms.

Thus, I can add a maximum of 66 feet of my double-strand-yellow scab wire, or 35 feet of my orange-double-strand wire to the circuit. This wire can be added anywhere in the circuit: between the panel and the igniters, between the igniters, or both.

Note: I always test my completed circuits to see if the actual resistance in the circuit is close to my calculated resistance. It is also important that all the matches in the circuit are the same type and have the same resistance. If one match ignites before the others do, because of differences in construction, then there is a good chance the rest of the matches in the series will fail to ignite.

• Parallel Wiring

This type of wiring connects all of the igniters directly to the firing panel (none to each other), or to the main scab wire individually like the rungs on a ladder.

A disadvantage to this circuit is that, since the current has more than one way it can flow, if even one electric match is good, the whole circuit will test “good” with the panel test light. A bad electric match will not cause the test light to remain dark!

Parallel wiring also will allow less scab wiring to be used out in the field.

The circuit above will only show an amount of resistance equal to the resistance of one electric match divided by two: 1.2 ohms divided by 2 = 0.6 ohms.

But, the circuit requires one amp of current for each igniter, or a total minimum of 2 amps of current.

So, with my 4.5 volt system, I can use a maximum of 50 feet of the yellow 2-strand wire, or 28 feet of the orange. The maximum allowable resistance in a circuit with two, parallel matches is 2.25 ohms.

Once again I always draw out a firing circuit, calculate how much resistance it ought to have, and check the actual resistance with my meter to check the circuit in actuality.

Here is a table which shows the maximum allowable length of each type of double-strand shooting wire, for 4.5 volt, 12 volt, and 24 volt systems, using either series or parallel wiring if multiple igniters are in a circuit.

# of Ematches	Max Resistance	Max Yellow wire	Max Orange wire
4.5 Volt System
1 match	4.5 ohms	100 ft.	55 ft.
2 parallel	2.25 ohms	50 ft.	28 ft.
3 parallel	1.5 ohms	34 ft.	18 ft.
2 in series	4.5 ohms	66 ft.	35 ft.
3 in series	4.5 ohms	28 ft.	15 ft.
12 Volt System
1 match	12 ohms	338 ft.	180 ft.
2 parallel	6 ohms	169 ft.	90 ft.
3 parallel	4 ohms	112 ft.	60 ft.
4 parallel	3 ohms	84 ft.	45 ft.
2 in series	12 ohms	300 ft.	160 ft.
3 in series	12 ohms	262 ft.	140 ft.
4 in series	12 ohms	225 ft.	120 ft.
24 Volt System
1 match	24 ohms	712 ft.	380 ft.
2 in parallel	12 ohms	356 ft.	190 ft.
3 in parallel	8 ohms	238 ft.	127 ft.
4 in parallel	6 ohms	178 ft.	95 ft.
2 in series	24 ohms	675 ft.	360 ft.
3 in series	24 ohms	638 ft.	340 ft.
4 in series	24 ohms	600 ft.	320 ft.

In the name of successful electric firing, I’d like to mention redundancy, and then repeat it.

If I have a critical item in a display such as a set-piece that I simply cannot allow to fail to ignite, I’ll actually run two firing circuits (cues) to it. If the first one fails, I have a backup.

If there is any doubt about the capacity of a circuit out in the field, I’ll remove the match from the firework device and test fire that circuit before the display. Then I’ll replace that electric match with a new one and reconnect it.

Often on items such as set-pieces, waterfalls, and firecracker walls, I’ll have two igniters and ignition points, wired in series. I’ll also have a length of quickmatch rigged up as an alternative manual ignition point in case the electric firing fails. I keep a propane torch by my side during the show, and will use it to manually light fireworks if necessary, and if it can be done safely.

Although some of these preparations may end up being unnecessary, they can save the day for you.

With each display I have one shot at having it go off successfully. I want to do all I can to insure that it does.

Stay Green,

Ned

Planning a Consumer Fireworks Display

Many of us really enjoy producing a nice fireworks display to entertain our family and friends, and to show off our pyro talents.

Over the past few weeks we’ve discussed making small Cremora fireball pots for such a show, and electric matches to use when firing them.

For many years a buddy of mine has hosted a large party, with a hog-roast and a bonfire, which has brought in hundreds of folks. I’ve presented a fireworks show annually at this event to cap off the festivities.

There’s nothing quite like putting in many hours of work and to have it result in that many people-adults and children-sitting in rapt awe as the show goes on, and erupting in joyful cheering at its completion.

I’ve had many folks compliment these small shows, comparing them favorably with the huge, commercial, downtown displays on the river. There’s just something about a small, intimate, family-and-friends setting, ending up with a nicely planned pyro display, all resulting in a really memorable event.

In the end, this demonstration of our pyrotechnic creativity, talent, hard work, and experience, and the entertaining of others with all of it, is really what this art form is all about.

To insure a safe and successful consumer fireworks display, there are some topics which merit consideration in the planning process:

• What are the laws governing such fireworks displays in my particular state, county, or city? Is there a requirement to have insurance for such a show?
• What is the site like where the display is to be presented? What sorts of fireworks devices will be appropriate and safe at that site?
• What is the budget for the show? Who will be paying for the fireworks, and when?
• Will the display be shot with accompanying music or not?
• Will the display be fired by hand, electrically, or with a combination of the two?
• Who will be helping with the display?
• What will be the length of the show?
• What devices will be employed in the show, and how will they be laid out at the site?
• What safety precautions are necessary?
• Will there be any reloading of fireworks during the show?
• How can we prepare for inclement weather?

All of this might sound like a bit of “overkill” to some of you. Having been involved in the planning and production of many small “backyard” displays and large commercial ones, I have learned the value of planning and getting as much of the work done prior to the day of the show as possible.

It’s quite amazing how much work there is to be done on the day of the show. If the above topics are addressed beforehand, and if enough work is done before the day of the show, then the chances of a safe, successful and enjoyable show are greatly improved.

This ain’t a fun subject, but it might be the one which can save you a lot of heartbreak and wasted money.

In the USA, there is no federal law regulating the use of consumer fireworks, only their production and sale.

But laws vary widely from state to state, and from locality to locality. In my state of Ohio, the display of all but “safe and sane” consumer fireworks is illegal. But around the Fourth of July many local law enforcement agencies look the other way unless they get a lot of complaints from neighbors.

In some other states anything goes. In others if you fire off a bottle rocket you’ll end up in the slammer pretty quickly, have all your fireworks confiscated and perhaps your car and home as well.

Only you can research your state and local laws, and determine for yourself what you can and cannot do.

Here in Ohio, I’ve chosen to get my state fireworks display operator’s license, to procure the necessary fireworks display permits, and to have a certificate of insurance for any display I produce. This gets the authorities-having-jurisdiction (AHJ’s) on my side, and I avoid having to be looking over my shoulder and waiting for the cop cars to pull up during the show.

And, if God forbid, there’s any property damage or injury, my permit and insurance are there to back me up.

Where will I be shooting the display? How big is the area; where will the spectators be; how close are the nearest structures and trees; how dry is the surrounding vegetation; and what sorts of fireworks will be safe to display there?

Some measurements with a measuring-wheel, and a simple sketch of the site can help a lot with the planning of the show.

On the sketch, I define the areas where the crowd will be. I show where I’m going to erect a barrier of stakes and caution tape, beyond which the spectators will not be allowed.

I also measure off the minimum distances needed to maintain safe separation between the crowd and the various fireworks devices. NFPA 1123 is the code which establishes these distances. These measurements not only insure compliance with the law, they also help insure the safety of the crowd during the display. These distances are as follows:

75 feet for ground display fireworks like fountains, strobes, small wheels, etc.

125 feet for large wheels with powerful drivers, and other powerful ground fireworks.

125 feet for smaller multi-shot cakes, etc.

70 feet per inch of tube ID for Roman candles, aerial shell mortars, larger multi-shot cakes, etc. (i.e., 125 feet for 1.75″ artillery shells, 210 feet for 3″ shell mortars, etc.)

I then determine the maximum size of the fireworks that I can use in a display fired at this site. I keep these limits in mind as I select the product for my show.

These separation distances assume that mortars, cakes, etc., are securely supported and/or barricaded. This protects the crowd from debris fallout and from a falling “dud” shell or device. If a mortar is not securely supported, falls over, and fires directly at the spectators, these distances will not insure their safety. Therefore, care must be taken to securely place and support mortars and cakes in the field prior to firing.

You’ll notice that rockets are not mentioned in the above safe-distance specifications. Rockets are not typically used in professional displays any longer due to safety issues regarding the fallout of sticks and spent-motors. Rockets are used often in consumer fireworks displays, though.

Often the flight of a rocket is unpredictable even if it is fired from a secure, stable, and vertical launch support. I personally would not fire rockets in a show unless I could insure that the spent rockets absolutely would not be coming down on the upturned faces of spectators as they watch the show, or on parked vehicles. Injury and insurance claims are not on my list of “fun things” at a fireworks show.

You can see from all of the above that I take all of this seriously. Many of us see multiple examples every year of folks who have had a bit too much to drink, take some cakes and mortar tubes out to the back yard or into the cul-de-sac, have adults with kids standing in front of them about 30 feet away, and start firing away, whooping and hollering.

Most folks get away with this. Some do not. They either hurt themselves, or worse, some innocent bystander. And, as a result, fireworks get more of a bad reputation. Nothing would take the fun out of all of this more quickly for me than hurting some kid with my “hobby.” I suppose I can’t emphasize the safety aspects of this enough.

How much can I spend on fireworks for my planned display?

Really! We’ve all gone into a fireworks shop, planning on picking up a couple of bags of fireworks for 50 bucks, and have walked out pushing two shopping carts full of brightly colored boxes after writing a check for $250.

Do you want your wife to be talking to you on the day of the show, and sitting there enjoying your artistry, with the house payment paid in full? Yeah, sometimes all of this feels a bit like an addiction, but I have to balance it in with all the other responsibilities in my life, and I hate fighting with my wife.

It might be $200 or $2000, but the budget helps a lot when it comes to actually picking out the fireworks to be shot the night of the display.

Will I be paying for the fireworks all by myself, or will some friends be pitching in? It is probably a good idea to get a commitment, and even the cash up front before the shopping trip.

Just a few things to think about.

It can be a lot of fun to record a soundtrack to be played during the fireworks show. On the other hand, sometimes it’s nice to just shoot the fireworks all by themselves, enjoying their rhythm and beat, and playing the whistles, reports, soft fountain hissing, color breaks, and rocket whooshes one after another.

I like to shoot a show to music if possible. In the kind of show we are discussing, I’ll simply choose some music based on the following criteria, and pick product that goes along with it. I don’t try to get pin-point precision choreography. I’ll save that for large, computer-fired shows.

Individual song download services like Napster and ITunes can be invaluable for finding and procuring great soundtrack songs.

One thing that I really think keeps an audience interested and entertained is variety. Folks are used to watching movies and television where there are ups and downs of emotion and action. Drama involves tension and relaxation, hard and soft, loud and quiet, slow build-up and climax. A good fireworks display will include the same.

We have found that, in general, 1-2 minutes of a particular song will keep an audience’s attention. After that length of time, their minds will start to wander.

I think it’s also important to keep the music recognizable. There are going to be loud fireworks going off which will obscure any music playing. I like to use a lot of hard-beats so folks can at least hear the beat of the song, and I also like to incorporate music in the soundtrack that folks will easily recognize and be able to follow along with.

Here are some possible musical themes to which appropriate fireworks can be choreographed:

• Patriotic songs: National Anthem, Taps, America the Beautiful, I’m Proud to be an American, etc. (Red/White/Blue fireworks, fountains, waterfalls, etc.)
• Kids’ songs: Lion King’s “Circle of Life,” “Ghostbusters,” “Linus and Lucy,” theme from Charlie Brown, etc.
• Slow beginning beat: The beginning of The Who’s “Won’t Get Fooled Again” (strobes)
• Light, humorous songs: YMCA, disco songs, etc. (aerial shells, cakes)
• Soft operatic songs: “O Mio Babbino Caro,” Andrea Bocelli’s “Por Ti Volare,” Israel Kamakawiwo’ole’s “Over the Rainbow” (falling leaves cakes/shells, soft shells one at a time)
• Dramatic songs: “Theme from the Last of the Mohicans,” Pirates of the Caribbean music, etc. (cakes and shells)
• Hard-beat finale songs: Hard Rock, Led Zepplin, Iron Butterfly, Queen, Black Sabbath’s “Iron Man,” etc. (hard-break and report finale cakes and shells,firecracker wall/tree)

There are, of course, too many songs and types of music to even begin mentioning them all, but the list above might suggest a place to start. One facet of a fireworks display which I really enjoy is the editing of a soundtrack which includes parts of 10-20 songs which I hope will entertain the crowd as fireworks go off to them.

I use Sound Forge
audio editing software to cut, splice, and edit my soundtracks. I’m sure there are other programs out there, many of which can be obtained for free, with which we can assemble a fun soundtrack for our show. A final firing-script with firing times is used to fire the show.

Large, precisely-timed displays are typically fired electrically, and often the firing is controlled by a computer program. This is a bit out of the range of most small display operators. But manual electrical firing can easily be incorporated into some or all of the show to improve the pace and the timing of the show, and to insure that particular fireworks are fired at exactly the desired moment.

The size of the firing system(s) will determine the number of cues (individual ignitions) you can incorporate into the display. If you only have a 12-cue system, there will be a maximum of 12 individual firings that you can have in the show, and the same goes for a 144-cue system.

But with creative fusing techniques it is possible, to greatly expand the number of fireworks and the duration of the display segment that is fired with each cue, though. We will be expanding on that idea in a soon-to-come Fireworks Tips article.

Some local fireworks clubs have yearly competitions in which a whole show is laid out on a sheet of plywood and the fireworks are fused together using various techniques for timing of the effects. The whole shebang is ignited using one firework fuse or firing cue.

Next week’s article will focus on tips for wiring a display with various firing systems and include some tips for fusing fireworks together to expand the versatility of the electric firing cues.

If some or all of the display will be fired by hand, it’s a good idea to have a scripted firing order and to have a firm idea of who will be helping to fire it. Rehearsing the firing of the display with all of the shooters will insure a smooth display after dark.

Hand firing safety is greatly enhanced by the use of a flashlight and propane torch, or a road flare taped to a stick. Head or helmet mounted flashlights are great during firing and post-display cleanup.

If there is to be any reloading of artillery (festival ball, reloadable) shell mortars during the show, this needs to be thoroughly planned. Safe ready-boxes, which will contain the product to be loaded during the show, and their locations need to be planned. Segments during the show, when product is being fired in areas other than the area where the reloading is going on, are the only safe way to perform this operation.

How long do we plan on having the fireworks show last? While it may be fun for us to take fireworks one at a time out to the shooting area and light them for hours on end, this may not be as entertaining for the crowd as it is for us.

Folks are used to being entertained for a half hour at a time with well scripted TV shows. A fireworks show that lasts 15, 20, or 30 minutes and has a lot of variety in it can easily keep folks entertained. Beyond that amount of time, you will probably start to lose folks’ attention.

Of course, the length of the show will depend on your budget. It’s a good idea to keep at least 25% of the product for the show’s finale, which might last a minute or two. So scripting the rest of the affordable fireworks in an entertaining way, overlapping their durations just a bit to avoid unplanned “dark sky,” will determine the show’s duration.

One way to increase the duration of the show, yet not put much of a dent in the budget, is to choose long-duration fireworks like fountains, strobes, wheels, and waterfalls, which can fill minutes of the display for a minimal expense.

This all leads us to a discussion of the actual product we will be firing during the display. All of this will be determined by the show’s budget, site constraints, choreography, and personal tastes.

One fun addition to a show can be some pre-dusk firing of daytime effects. There is an increasing variety of daylight devices: smoke, Sky Lanterns, and streamer and parachute cakes. Kids love to run, chase, and try to catch the parachutes and streamers. Just make sure that the cakes produce fallout which is not still hot or otherwise dangerous for this kind of activity.

One really great way to pick out the product for a show is to attend the product demo at your local fireworks store. My friend Brian Lynch owns a store nearby in West Harrison, Indiana, Half Price Fireworks. Brian actually goes to China and hand-picks his favorite new devices for his shop. Often, these local, independent shops can give you the most bang for your bucks.

I attended one of Brian’s product demos recently, and was handed a checklist/note-taking-sheet to use during the demonstration. Before the devices started to be fired, I organized my note-taking to include notes about these various aspects of the product:

• Height of fireworks display–low-medium-high (one way to increase the variety in a show is to use various parts of the background (the sky): ground level, low sky, and high sky
• Loudness of the firework (more variety can be planned if soft-medium-loud sections of the show are scheduled)
• Quality of the firework, rated on a scale of 1-5
• Duration of the display of a firework device (I brought a stopwatch to use to record this time)
• Notes of the crowd’s reaction to a firework (laughter, WOW applause, quiet awe)
• Cost of the firework, and its value for the money, (i.e. 12 seconds of a nice cake for $16, a line of soft-strobing fountains which last over a minute for $4)

Based on all of the above information from the demo combined with the show budget, site limitations, and choreography, I now select my product for the show, getting the plan down on paper before strolling down the aisles of the shop.

One additional nice feature that many shops provide, including Brian’s, is a label near each item which indicates the product’s duration, effect, and often an actual photo of the firework in action. This info can add to that which was gained at the product demonstration.

The layout of the planned devices can then be added to the sketch of the display site. Device variety, loudness variety, display height variety, and changes in durations and pace, all serve to keep the crowd interested in the show.

The safe use of some homemade firework devices, such as the Cremoras detailed in Cremora Fireballs, can really enhance a display while only lightly impacting the budget.

If there is to be hand-firing during the show, safety gear such as safety-glasses, hardhats, gloves, long-sleeved cotton shirts/jackets, and hearing protection will be in order.

A five-gallon bucket of water for cooling off any possible burned hands, etc, is a good idea. Pump-up garden sprayers or a pressurized garden-hose/nozzle serve as fire extinguishers.

Have a first-aid kit on site.

Small radios or walkie-talkies can enhance communications between shooters during the show.

A barrier of caution-tape, stretched between fence posts, serves to keep the spectators in their designated areas before, during and after the display.

Thorough cleanup after the show, and a careful inspection of the site at daybreak following the display, serve to keep unfired fireworks out of the hands of children, who love to find and light or disassemble such items, often with disastrous consequences.

What are we going to do if it rains? A few years back I helped on a show worth tens-of-thousands of dollars. It was a hot, sunny July day, and the weather forecast predicted the same weather right through the evening. A half-hour before show time, a black, rolling wall of clouds formed on the northern horizon, and within 15 minutes the wind was howling and a hellacious thunderstorm rolled in.

In the wind, there was no way to use tarps or plastic to cover our mortars and cakes, and the long waterfall and the set pieces were completely vulnerable. We lost the whole show, and had stacks of wet aerial shells and box-cakes that had to be somehow salvaged or disposed of safely. A real mess!

These types of experiences motivate most of us experienced display producers to take precautions against the ravages of inclement weather, no matter what the forecast is. I like to say, “If you don’t want it to rain, cover everything up. If you want it to rain, act as if it’s not going to.”

Rolls of plastic or aluminum foil, and plastic tarps, work well to cover racks of mortars. Large plastic bags cover up individual cakes, and rolls of plastic stretch-wrap can be used for mortar racks, lines of fountains, etc. It can be hard to cover and protect a firecracker wall or a waterfall or set piece, so sometimes it’s best to leave them lying on the ground and covered with plastic until the last minute if there is a questionable forecast.

With planning centered around all of these subjects, a successful, relatively stress-free, safe, and fun fireworks display can be produced. Most folks will never know the amount of work that goes into a good show, but they also will never get to experience the satisfaction that comes from creating such a work of art and hearing the audience’s cheers during and after it.

In the next few weeks, we’ll be focusing more on the electric wiring and fusing of a display, the assembly of mortar racks and supports for wheels, firecracker walls/trees and waterfalls, and the actual layout/placement/assembly/support of a consumer fireworks show.

Stay tuned and stay green,

Ned