Here’s your link for Turbo Pyro:

http://www.turbopyro.com

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I DON’T KNOW WHETHER YOU HEARD THIS YET
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I’ve added *more* stuff to Turbo Pyro. I want to make sure you have fun with your projects, so I added a bonus Smoke Bomb Kit and project–Making Jumbo Smoke Canisters eBook (including videos).

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

Grab yours here:

http://www.turbopyro.com

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

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

Harry

Turbo Pyro goes LIVE at 12:00 Noon Eastern time today, June 19th is a post from: Confessions of a Fireworks Man

In this article I am going to describe a way that I make 4″ plastic ball shells. I want to emphasize the “One Way” part of this article’s title, though.

In Volume 2 of Bill Ofca’s Technique in Fire series, Design and Quick Assembly of 3, 4, and 5 Inch Plastic Ball Shells, some interesting and useful methods are described, and it was this booklet that I followed when I first started building plastic ball shells years ago.

Lloyd Sponenburgh has another way of building these aerial shells, as described in his Passfire.com
article, 4″ Plastic Ball Shell. I’ve played with Lloyd’s methods a bit as well. At regional club events, he has taught probably hundreds of folks how to build these firework shells his way.

One thing that I’ve discovered over the years is that there are many ways to skin the cat in fireworking, and that there is much we can learn from each other. Usually each of us adopts a hybrid, personal way of doing things. And, each person’s way can change and evolve over the years.

I do think my methods include some unique ways of approaching the subject, and I hope the information in here can be useful to both the beginning fireworker and the seasoned pyro who is curious about how someone else does things. Suffice it to say, I am very pleased with how these shells perform using my method.

So, this article is simply a description of my current, personal, hybrid way of building these shells. But my way will probably evolve to be a little different in a year or two. Beyond just discussing how to build one of these shells, though, I’d like to ponder how to think about some of the various aspects of the shell’s construction.

First, look at the basic design of a 4″ plastic ball shell in the diagram below.

Next, you may want to review the following articles. Parts of this project depend on the referenced articles below.

• Making and Testing High Powered Black Powder
• How to Make Cut Firework Stars in an Hour or Less
• How to Make Wonderful Zinc Firework Stars
• The making blackmatch and quickmatch sections of Firework Shells in 2-1/2 Days: Part 2 and Part 4
• The shell construction details in Nice Shells in 2 1/2 Days, Part 3

• 4″ spherical shell set (Skylighter #PL2060)
• Approximately 1# of stars
• Approximately 4 oz. of break charge/burst powder
• Optional slow flash burst additive
• Approximately 2 oz. of lift powder
• 30″ of quickmatch (or fast fuse and foil duct tape) (Skylighter #GN3001, or #GN1205)
• 4″ Visco fuse (Skylighter #GN1000)
• 2″ piece of 1/4″ time fuse (Skylighter #GN2000)
• Cross match, (blackmatch or Visco cross-match, Skylighter #GN1010)
• One piece of printer paper
• Fiberglass Reinforcing strapping tape, or gummed kraft tape
• Plumber’s heavy-duty PVC cement
• Lift cup
• Hot glue and glue-gun
• Tissue paper (Skylighter #MS1110)
• Thin string
• Weighing scale (Skylighter #TL5020, #TL5030)
• 4″ Fiberglass Mortar Tube (#PL3184)
• Shell support tubes
• Sharp, single-edge, razor blade
• Aluminum foil duct tape
• Rice Hulls (optional) (#CH8236)

In Fireworks, the Art, Science and Technique (FAST), Dr. Shimizu includes a table on page 252 which lists firework shell sizes, and the corresponding recommendations for star size, number of stars, and amount of bursting charge. Based on that firework star sizing information, I’ve developed the following little graph:

This graph, of course, only shows a starting point when sizing stars for a shell. How fast does the star burn? Some burn much faster than others. Do I want a dense burst of smaller stars, or a Palm Tree burst of very large stars? The individual fireworker must experiment and develop their own personal preferences.

The chart shows that a good starting point would be 7/16″ stars for this 4″ ball shell. The FAST chart also indicates that approximately 170 round stars of this size would be used in the shell. But I’ll be using cut stars in this particular shell, so that number will probably vary.

The weight of the stars in the shell will vary considerably with the type of star. It might take only 8-10 oz. of a lightweight star such as Willow, or up to almost a pound of a dense star like a zinc star.

In the booklets cited above Ofca and Sponenburgh employ variations of a flash powder bursting charge, with Lloyd combining his hot-flash powder charge with some black powder.

In Shimizu’s FAST, pages 207-214, there is an extensive discussion of potassium chlorate bursting charge (H3), potassium perchlorate bursting charges (KP), and black powder bursting charge (BP). Various considerations are discussed, and possible cores for coating the charges on are explored, as well as coating ratios.

For shells smaller than 4″, Shimizu recommends the H3 burst charge, and for larger shells he specifies either the KP or BP burst powders.

I personally like to stick with black powder burst charges, sometimes augmented with a slow flash powder burst additive, which I’ll describe later.

An interesting subject is the density of various burst charges. These can be useful to know when choosing a burst powder for a particular shell.

Once again, in the FAST chart cited above, specific amounts of burst charge are specified for particular shell sizes. A little calculating will show that a burst charge density of 0.45 oz./cubic inch is specified for 3″ shells, 0.31 oz./cubic inch for 4″, and for shell sizes 5″ through 12″, a burst charge density of approximately 0.25 oz./cubic inch is recommended.

So, for our 4″ shell, our granulated BP with red-gum/alcohol and having a density of 0.35 oz./cubic inch is just about perfect.

I have 1/4″ time fuses that burn anywhere from 2.2 to 3.1 seconds per inch. I want a 2 second delay from my time fuse in this 4″ shell. I’ll typically use a time fuse delay (in seconds) of half the shell’s diameter. So, I need an actual time fuse length, between cross-matches, of between 5/8″ and 7/8.” I could just split the difference and use 3/4,” but I like to be more precise in my fireworking.

I have a new roll of time fuse and I don’t know how fast it burns. So, I cut 10″ of it, lay that piece on the ground in a safe location away from any flammables, light one end of it with my torch at the same time that I start my stopwatch, and I stop the stopwatch when flame spurts out the other end of the fuse.

This 10″ piece of fuse burned for 21.65 seconds, which is close enough to 22 seconds for me. Dividing that 22 seconds by the 10 inches gives me a fuse burn rate of 2.2 seconds per inch. I put a masking tape flag label on one end of my roll of fuse indicating its burn rate for future reference.

I’m a bit on the particular side. My wife would say that I’m a bit compulsive and anal, but I know she’s just kidding. I hope. Anyway, I actually cut 10″ from each end of the roll of this fuse and time each of those pieces. Each one burned for about 22 seconds, so I know that figure is accurate for this roll of fuse. Heck, how do I know for sure that the machine and operator making this fuse stayed consistent the whole way through?

Using this fuse then, I’ll make sure that I have my desired delay of 2 seconds, divided by the 2.2 seconds/inch, equaling 0.9 inches of time fuse between cross-matches. This is almost exactly 7/8.”

Well, I think we can start to actually build this baby now.

I heat the hot-glue gun up. I have had good luck with Arrow glue guns and glue sticks from Home Depot. A gun and a bag of sticks for under $25.

Note: For hot-glue-gun safety tips, see Nice Shells in 2-1/2 Days: Part 3.

I want 7/8″ of actual time fuse delay, and I’m gonna split each end 1/2″ with my razor blade for cross-matching. So I cut a 1-7/8″ piece of the time fuse with the razor blade. I put marks with a Sharpie in 1/2″ from each end of the fuse.

Warning: Fuse is never cut with scissors because it can be ignited by the friction of that kind of cutting. Fuse is always cut with a razor blade, or with an anvil cutter that uses a razor blade for the cutting.

Then I carefully split one end of the fuse down 1/2″ (the actual blade on my razor is 1/2″ wide), insert three 4″ pieces of the cross-match, and tie the split ends of the fuse back together with string and a clove hitch knot and an overhand knot to secure the clove hitch. I split the fuse right down its center, disturbing the black powder core as little as possible.

Note: Skylighter’s Super Fast Paper Fuse (#GN1205) has 3 strands of thin black match in it which are perfect for cross-matching.

I hot-glue the fuse-washer onto the correct hemisphere.

I then give the fuse a trial fit in the hemisphere fuse hole to make sure it inserts easily. If it does not, it is OK to slightly enlarge the hole with a correct diameter drill bit and drill.

When I know the fuse will fit in the hole easily, I apply a bead of hot-glue around the middle of the fuse. Then, with the cross-matched end inside the casing, the fuse is quickly inserted into the casing while the glue is still hot. (When the fuse is inserted into the hemi, the hot glue becomes a seal between the fuse and the hemi, being dragged with the fuse into the casing and forming the fillet on the inside.) I push the fuse through until the fuse’s outside Sharpie mark is about 1/4″ beyond the outside edge of the fuse-washer.

Then, I apply hot-glue around the fuse outside of the shell, filling the recess in the fuse washer, and building up another fillet of glue around the fuse.

Note: These hot-glue fillets, inside and outside the shell casing, are very important. They keep the lift gasses out of the shell when it is launched skyward. For this reason, the glue seals must be solid and secure, without any gaps.

A passfire tube is made of a 1-1/2″ x 4-1/2″ piece of paper, rolled up on a 3/8″ dowel. This tube is inserted over the cross-matched fuse in the shell casing, and embedded in a ring of hot-glue to seal it to the casing. This tube conveys fire to the center of the shell after the time fuse burns through to the cross-match, which improves the symmetry of the shell’s burst. It doesn’t hurt to insert a few more pieces of blackmatch into the passfire tube at this time to increase fire transfer to the shell’s center.

A 1/8″ hole is drilled all the way into the un-fused hemisphere, through the recess where the lift ring will eventually be installed. This vent hole will allow air to escape from the shell when the two halves are glued together. If this hole is not drilled, the air will have to escape from the equator, which may very well leave voids in the equatorial seal. This could, in turn, let lift gasses in and cause a “flowerpot.” (A flowerpot is a shell bursting in the mortar and performing like a mine.)

Now, as described in Skylighter Fireworks Tips #93, I put the shell casing hemispheres on sections of PVC pipe which serve as work stands, and I lightly hot-glue rings of stars in the hemis flush with their equators.

Note: It is important in the un-fused hemi, that you glue and position the stars below the equator’s recessed edge, so that the halves will mate when the shell is closed.

Then the remaining stars are fitted into the casings without any gluing. The little wedge shaped stars that were created in the star-cutting process come in handy for filling odd-shaped voids.

Now, I line the shell and cover the stars with tissue paper, fill the centers with homemade, granulated black powder burst charge, loosely dump in the optional slow flash powder booster (see note below), and tap the casings to settle the powder. Then I cover it all with, and glue on, discs of tissue paper after trimming the excess tissue paper off.

Note: I’m very careful when it comes to clipping the excess tissue paper off with scissors. I never cut through any paper that has burst powder on it, and I keep the scissors clear of any area of the paper that does.

The optional slow flash burst powder does not have to be used, and typically it would not be used for a softly-breaking shell like a Willow. It can be used in a shell where a hard, symmetrical break is desired.

This powder is a 2/1/1 mixture of potassium nitrate, sulfur, and American-dark or any 325 mesh bright flake aluminum. The individual chemicals are individually screened and are only mixed gently by rolling them together on a piece of paper. This is called the diaper-method of mixing flash powder.

For this 4″ shell, I used 0.6 oz. of the slow flash powder, which was made of 0.3 oz. of the potassium nitrate, 0.15 oz. of sulfur, and 0.15 oz. of the aluminum.

Now it’s time to close this shell up. I use heavy-duty PVC plumber’s glue to glue the shell halves together. Using the glue can’s applicator, I apply glue liberally to the mating surfaces of each hemisphere, and close the shell, twisting the hemis together until they won’t move any more. I then wipe the excess glue off with a piece of kraft paper, and reinforce the seal/joint with masking tape, pulling the two hemis together as I do so.

Using the same glue, I fasten the leader-hook/lift-ring, which securely seals the vent hole we drilled.

I apply 4 rings of reinforcing, strapping tape, one around the equator, and the other three evenly spaced, striving for a finished shell circumference of 12.” Each ring of tape is 3 layers of tape thick.

I like to cover the shell at this point with aluminum foil duct tape to flame-proof the strapping tape, and to make the shell look a bit more presentable. I also split, cross-match, and tie the outside of the time fuse in the same way that I did the inside of the fuse.

I have found that Skylighter Super Fast Paper Fuse
can be wrapped in foil tape, which has been cut down the middle to form 1″ wide tape, in order to create very nice quickmatch if one cannot buy or does not want to make their own.

I cut a piece of quickmatch 30″ long and make sure bare black match is sticking out 1″ from the end that will be in the shell’s lift powder. I weigh out 1.5 oz. of commercial 2FA black powder, or about two ounces of homemade BP lift powder, put it in a thin plastic baggie, insert the bare match end of the quickmatch leader and tape the baggie closed. I cut the excess plastic off, and tape the baggie securely to the leader.

Then the baggie of lift powder is centered on the shell’s time fuse, then covered with a lift cup which is hot-glued in place, and the leader is routed as shown. For a lift cup, a cone-shaped drinking cup can be used as shown. A flat bottom paper cup or a homemade, funnel-shaped paper lift bag can also be used.

I like to hot-glue the leader to the side of the shell to further secure it, and then I tape some visco safety fuse into its end.

At this point a label can be affixed to the shell to identify it, if so desired.

This is how this 4″ zinc star-shell broke. You can see that it is a nice, big, round, symmetrical break. Just what I was looking for.

Have fun and Stay Green,

Ned

Really Nice 4″ Plastic Ball Firework Shells is a post from: Confessions of a Fireworks Man

This is a continuation of a series of articles that details the production of good, traditional, paper ball shells in a minimum timeframe, possibly at a three-day fireworks club event. I’m exploring the possibility of arriving at the meet with only a few chemicals, some other materials, some tools and equipment, but with no completed pyrotechnic compositions, and then producing these firework shells from scratch.

The original series of articles ran in 2007 in the Pyrotechnics Guild International’s Bulletins #152-155, and this is a somewhat revised and expanded re-issue of that series.

Part 1 – How to Make Charcoal, detailed the charcoal options for this project. It included the production of homemade charcoal to be used in the various components of the shells. The charcoal-making step of the process would occur at home prior to travelling to the pyro get-together.

In Part 2, making black powder (BP) shell burst granules, black match, shell lift powder, and charcoal tailed stars were begun. Options for star rollers, drying chambers, hydraulic presses, star plates, and homemade shell casings were also discussed.

Today I want to check on how dry the items in the drying chamber are. I also want to granulate the BP pucks, prime the stars and finish drying them, make the spolette time fuses, assemble the shells and paste them in so that they can dry overnight.

I woke up this morning wondering how everything in the dryer was doing. I opened it up, took two stars out of the top screen, and tapped them together. I’ve learned that when they are pretty dry they produce a crisp, clacking sound like two stones being knocked together. The stars are doing just that.

I then took a couple of the stars out to a safe place and lit them one at a time with the propane torch, tossing them into the air when lit. They both ignited well and burned with nice spark trails, burning out just after hitting the ground. This is just how I want this star to burn.

Back in the drying chamber, under the star screens, I unearthed the screen with the BP pucks on it. I stacked the pucks up and weighed them. Yesterday, I started with 20 oz. of mill dust and added 2 oz. of water, so when the pucks are totally dry they ought to weigh 20 oz. again. They now weigh 20.2 oz, so they have just a bit to go. When the pucks are completely dry, they “clink” when they are tapped together, sounding like pieces of pottery or china. This morning they have a slightly duller sound.

I cut a 6″ piece of the black match off of the match frame and took it out into the field to light it. It was nice and stiff and it burned well and consistently.

And, from one of the bottom frames, I removed a very small handful of the burst granules. Putting them on a rock out in the field, I inserted a 6″ piece of the blackmatch and lit it. Great. A quick poof and the puffed rice cores disappeared in the flame. Good and dry.

Ah, life is good. Warning: I have a buddy who wanted to demonstrate how his BP rough powder burned. He made a pile of it and lit it with the torch. The whole backside of his arm got badly burned. Always test burn compositions and devices by installing a piece of fuse so that you can retreat before it all ignites.

Now I want to crush the black powder pucks and screen the granules into usable sizes. First, I put a puck in a little plastic baggie. Then I put the baggie on top of my 6×6 pounding post and whack it with a metal-headed meat-tenderizing hammer until the puck is busted into about 2FA (about 1/4 inch) size granules.

I do this with all the pucks, one at a time, and dump the BP into a 4 mesh sorting screen.

I sift all the granules out that will pass through that screen, and re-crush the granules that won’t pass through, until all the BP has passed through that screen and onto a sheet of kraft paper.

Then I pass that pile through an 8-mesh screen. The granules that won’t pass the 8-mesh, but have passed through the 4-mesh are dumped onto a paper plate, and are the 2FA lift powder, which will propel the finished shells into the air. (See black powder size charts.)

I then pass the remainder of the powder through a 12-mesh screen, and the powder that has passed through the 8-mesh but won’t pass the 12-mesh forms a pile of 3FA when dumped on a plate.

Doing the same thing with a 20-mesh screen kitchen colander separates the remaining powder into 4FA (same size as FG) and meal powder. What passes through the 20 mesh colander is Meal powder. What doesn’t pass through that colander is 4FA.

I wanted to end up with 12 oz. of 2FA for lifting the two 8″ firework shells, and I actually ended up with 14.3 oz. of it. So I weighed out and set aside 12 oz, and further crushed up the extra 2.3 oz. of the 2FA, along with the 2.5 oz. of 3FA, until it was all sorted into the 12 ounces of 2FA, 4.8 oz. of meal powder and 2.75 oz. of 4FA.

I measured 1 oz. of the meal powder onto a paper plate, and put it back into the dryer to use later in the making of the spolette time fuses. I also spread the 12 oz. of 2FA lift powder out on a screen and put it back in the dryer to insure that it is completely dry when I use it.

Lift Powder Note. I’ve compared black powder made this way with commercial BPs. In tests performed with baseballs shot out of a 3″ mortar, to produce a 300’ high flight (6.5 second flight time up and down, 4.33 seconds of fall from apogee to ground), the following powder amounts were needed:

0.35 oz. 3FA made from pine charcoal
0.45 oz. Commercial charcoal 3FA
0.55 oz. Wano Brand BP 3FA
0.75 oz. Pine charcoal 2FA
0.75 oz. Commercial charcoal 2FA
0.75 oz. Wano Brand BP 2FA

Testing with 6″ dummy shells, 2 lb.-6 oz. shell weight, using 3 oz. of lift, produced the following results:

So, I’m confident that making BP with the SPF (spruce/pine/fir) homemade charcoal, or with commercial charcoal, produces results that are comparable with willow charcoal and commercial powders.

Note: In a future article, I’ll be detailing various black powder production methods, and procedures for testing the various powders and comparing them with each other. Stay tuned.

Now I want to prime one end of each star. With the black powder break charge that I’m using in these shells, these stars will probably all light without priming. But I like to be on the safe side. The primed end also adds a bit to the break, and speeds up flame propagation on the star.

I mix 0.2 oz. of dextrin with the 3.8 oz. of BP meal and wet it with some water to make a prime-slurry in a plastic tub. Using a little paint brush, or at other times dipping the end of the star into the slurry, I wet one end of each star with the prime-slurry. Then I press the wet end into the 4FA to form a rough, granular-primed end on each star. It took me an hour to prime all the stars and put them back in the dryer.

Note: The method of priming stars outlined above is not my favorite or standard method. I employed it in this project to speed the process up, since the stars can be primed, dried, and assembled in the shells the same day.

My regular method of priming these 113.9 ounces of stars would be as follows:

• Make a “scratch-mix,” BP prime by screening together:

  Component	Weight
  Potassium Nitrate	24.9 oz.
  Airfloat Charcoal	4.9 oz.
  Dextrin	1.7 oz.
  Sulfur	3.5 oz.
  Total Weight	35 oz.

  (This is a 15/3/2/1 ratio of the ingredients)

  (Referring back to Part 2 of this series, 21 ounces of BP mill-dust, including dextrin, was set aside from the second ball-mill batch. This could be used as part of the above prime. To this 21 ounces, 9.9 ounces of potassium nitrate, 1.9 ounces of airfloat charcoal, 1.5 ounces of sulfur, and 0.7 ounces of dextrin, would be added and screened into the mill-dust to make the prime.)

• Divide the stars into five lots, about 23 ounces each lot
• Divide the prime into five batches, 7 ounces per batch
• Put one lot of the stars into the star roller

  

  Small Star Roller

  (This is assuming that I’d be using my smaller, stainless-steel pot roller. If I was using my larger, cement mixer roller, I would experiment with priming 2 or 3 of the 23 ounce lots or even all of the stars at one time.)

• Out of one of the batches of prime, take 1/4 cup of the prime powder, place it in a paper cup, and add 2 tablespoons of water to it, stirring to mix up a thin prime “slurry.”

• Start the star roller with the 23 ounces of stars in it, and dump the slurry onto the rolling stars, using gloved hands to thoroughly coat the stars.

• Slowly add the remaining dry prime powder out of the 7 ounce batch, 1/4 cup at a time, working the stars with the gloved hand to keep them separated, and spraying with water as necessary, until all the prime has been taken up by the stars and they have a nice, solid, “crusty” looking coating of prime on them.

• Dump that batch of stars onto a drying screen
• Prime the remaining 4 lots of stars in the same manner

The disadvantage of this method, from the viewpoint of this project, is that it takes 24 hours for the stars to completely dry. If I had that extra day, I would employ this method for the star priming.

10:00 am – 12 noon. Take a little break and let the stars and spolette meal powder dry completely.

12 noon – 12:30 pm, Make spolettes.

I’m making spolette time fuses for these shells, rather than using commercial time fuse, because I want to make the shell completely from scratch, using only a couple of chemicals.

Note: From Traditional Cylinder Shell Construction, Part I, Pyrotechnica IX, by A Fulcanelli, “The spolette is the oldest and most versatile type of shell fuse. It consists of a small-bored and relatively thick-walled tube, charged partially with pure commercial meal powder.”

Pyrotechnica IX and XI contain the complete “Fulcanelli” series on this type of shell construction, and those of us who are familiar with this resource can’t recommend it highly enough.

I have found that my homemade BP meal powder, such as that which was derived from the corned pucks above, works very well in spolettes.

My spolette tubes, which I’ve had for awhile, are 3/8″ ID, 1/16″ wall, 2.25″ long, parallel wound tubes. (Skylighter sells some nice spolette tubes which are just a bit larger in OD.) I want 4 seconds of timing for the 8″ shells, and based on Fulcanelli’s figures, that ought to be about 1-3/8″ of solid powder, plus 1/16″ at each end for scratching back, for a total of 1-1/2.”

First, I cover one end of a tube with masking tape and ram it with that amount of powder, using my 3/8″ solid aluminum rod rammer, a little aluminum puck ramming base, my rawhide mallet and my 6×6 pounding post.

I pound 1/8 teaspoon at a time, which produces 3/16″ increments, until I have a solid powder column in the tube 1.5″ long. Then I scratch both ends of the solid powder core with an awl to a depth of 1/16,” and attach a piece of visco fuse with masking tape.

Burning that spolette in a safe location, and timing it with my stopwatch, reveals a time of 3.2 seconds with this black powder. I recalculate the length of the powder core I’ll need for 4 seconds, and arrive at 1-3/4,” plus 1/16″ inch on both ends for scratching back.

I make a spolette with 1-7/8″ of powder, scratch the ends, burn it and time it, and get 4.1 seconds. Perfect. I then pound two spolettes with the 1-7/8″ powder column (this takes 0.2 oz. of powder for each spolette) and scratch the inside powder with the awl. Note that the finished spolette has powder flush with one end of the tube and covered with masking tape, and leaves 3/8″ of the tube still open and not filled with powder.

Note: A friend recently gave me a nice tool set for making spolettes. It is similar to what Rich Wolter makes (wolterpyrotools.com) and may have been made by him. It has been machined to work with the size tubes I am currently using. The grooves on the shaft of the ram, 1/4″ apart, come in handy for gauging the height/timing of the powder column which has been rammed.

I’m using commercially produced, Chinese, strawboard hemispheres for these shells.

My spolette has a 1/2 inch outer diameter. So, using my half inch steel punch, I knock a hole in two of the hemis, using my rawhide mallet and the 6×6 pounding post.

Note: Awhile back I purchased an inexpensive set of gasket punches at http://harborfreight.com/. These punches come in handy for punching holes in stuff like the shell casing above.

I then hot-glue the spolettes in the two hemis, forming nice fillets of glue on both the inside and the outside, allowing 1″ of the flush end of the spolette to stick out on the outside.

I removed the masking tape to insert the spolette. Now I cover the outside end of the spolette with tape again, making a little “flag” with the tape for orientation during the pasting process.

On the inside of the hemi, I take a 5″ x 5″ piece of 40# kraft paper and make a passfire tube with three turns of the paper rolled up on a half-inch dowel. Then I hot-glue the tube over the spolette tube. I’ve enlarged the dowel just a bit with some masking tape to make sure the passfire tube will fit over the spolette tube.

Sighting across the plane of the hemi equator, I use scissors to clip the passfire tube off flush with that plane. I then insert two pieces of black match, making sure they fit down into the spolette tube and are pressed against the scratched column of black powder, and sticking out of the passfire tube about 1/2.” I then tie the end of the passfire tube with a clove hitch, and use my awl to punch a vent into the passfire tube below the string.

Note: here’s where you can see one way to tie a clove hitch knot.

The clove hitch is the most-used and versatile knot employed in fireworking, and there are several ways to tie one. At one time, I spent some time sittin’ in my LaZBoy chair, with a piece of string, and practicing the various ways of tying a clove hitch until they became second nature.

I remove my stars from the dryer and try to pry the prime off of one of them. The prime is very hard and dry, and pulls off some of the star along with it. This indicates it is thoroughly dry and fully adhered.

I like to hot-glue my stars into the hemis with a small stripe of glue on each star, applied to the end opposite the primed end, beginning with the stars at the equator. I use four rings of 4″ PVC pipe as stands for the hemis during this process.

I glue the stars in about 1/8″ below the equator because the angle of the hemi brings the inside edge of the stars just above the equatorial plane, where they will mesh with the stars in the other hemi.

I then fill the rest of the hemis with stars, lightly gluing each one in.

In a few cases I chip off edges of stars with a knife to allow a spot to be filled with another star. (I do this outdoors in a safe location.) Each hemi holds about 72 stars, for 144 stars per shell.

After filling all 4 hemis, I have 215 stars left over, enough for another shell and some rising tails. (I could have made 2/3 of the stars in the original batch if I wanted to avoid having these extra stars to dispose of. Maybe I can rustle up some more BP and make a mine or two.)

I remove the burst powder from the dryer, line the stars in each hemi with tissue paper, and fill the tissue with the burst charge, clipping off the extra tissue paper with scissors. I allow the burst to project above the hemi just a bit. When I mate the two halves of the shell, I want to have to work a bit at doing so, so that, once they are mated, the shell contents are tightly packed in place.

Note: At some point, if you’re like me, you’ll say, “Heck, I don’t need to keep that old burst powder separate from the stars with that tissue paper. I’ll just dump the burst in on top of the stars and work it into the voids.” Yep, that’s what you’ll say, and that’s what you’ll try, and then, after you close the shell and continue to work on it, the burst will migrate further in between the stars, and the burst and stars will start to loosen up, and the contents of your shell will start to rattle around, and your shell burst will look asymmetrical and ragged, or else the shell will flowerpot on lift (break in the mortar when it is fired).

Then you’ll say to yourself, “Well, that was a good experiment and a valuable lesson learned.”

And, you’ll go back to using the tissue paper. Yesiree.

I then close each hemi with a circle of tissue paper, hot-glued to the equatorial ring of stars. This paper disc is easily made by taking a square of tissue paper slightly larger than the casing, folding it in half, then quarter, then eighth, etc, and then clipping the folded paper off to the right length, as shown.

Note: There has been quite a bit of conversation in pyro-circles about the safety of using hot-glue when fireworking. The heat of the glue is not a problem, being well below the ignition temperature of the commonly used compositions. The problem can arise, if and when the hot-glue gun malfunctions, and possibly emits sparks. Some pyros allow their guns to heat up, and then unplug them before gluing.

The general consensus is that the most important safety precaution when using a hot-glue gun is to keep the gun on its stand, or sitting in a “garage,” like a length of PVC pipe, when it’s not in use.

That also keeps its innards from getting gummed up with excess glue, a common cause of malfunction. If one lays the gun down on its side while it’s being used, the excess glue ends up all over it, and some ends up seeping into its bowels. My guns, when used this way are a mess. But when a gun is stored during use with the tip pointing down, either on its stand or sitting in a “garage,” the excess glue just drips off the tip. The glue stays new, shiny as the day it was born, and not all gummed up inside.

It’s also probably a good idea to avoid using those “dollar-store,” el-cheapo hot-glue guns.

Now it’s time to mate the hemis by flipping one of them over quickly and onto the other one, and then setting them tightly against each other by applying pressure with my hand and lightly tapping with my rawhide mallet. Then the hemis are secured together with high-adhesion masking tape.

I know what you’re asking, “Does this guy ever take a break or eat?”

I am determined to get these shells pasted-in and in the dryer before dark and the beginning of the evening’s festivities. And, no, nobody ever accused me of passing up on a meal.

“Pasting” a shell is the process of applying layers of reinforcing paper onto the exterior of the assembled shell hemispheres.

I mix up some wheat paste (the good stuff from pyrosupplies.com) in my blender until it is about the consistency of yogurt. Wheat paste is the old-fashioned wallpaper paste. I know, I know, how would you fellas, who are reading this, know what the consistency of yogurt is? Real men don’t eat yogurt. Go buy a little tub of it and check it out. I like strawberry. (No, you cannot paste your shell in with strawberry yogurt!). But I digress.

I like to paste 8″ shells with 1″ x 9″ strips of 40# virgin kraft paper. I have an 18″ wide roll of this paper in a dispenser. I tear off twelve 9″ long sheets, and do this four times, making 4 stacks of 12 sheets. I am going to use one stack of 12 sheets for each application.

I can only cut through 6 layers of the paper with my sharp knife (which I keep really sharpened). So I paste up 6 pieces of the paper on my cutting board. I apply paste to the cutting board; paste both sides of the first sheet and then lay down the rest of the sheets, feathering them as I go, and pasting only the top side of those 5 sheets.

Now, after marking my 1″ widths with my marking screw-board (there are screws every 2,” and I eyeball the intermediate cut marks), I cut the sheets into 1″ wide strips.

Now I pick up one stack of 6 strips at a time, and lay down 9 of the stacks on top of each other, feathering the ends as I go. Then I roll them up into a little roll.

I do this twice for each cutting board batch, and there are two of these batches for the total of 12 sheets, so I end up with 4 of the little rolls of strips.

By the way, this paper and this method require no “breaking” of the paper. (Breaking paper, as described by Fulcanelli, entails crumpling it up to incorporate the paste and break the grain of the paper.)

The first thing I like to do is to brush some paste onto the shell and smear it around with my hands, preparing the shell casing so the pasted strips of paper will really adhere to it.

I like to apply the strips in the “9 axis system” described by Jim Widmann in his PGI Bulletin article, Bulletin #123, March/April 2001. This system uses the 3 main axes, x/y/z, as well as the 6 intermediate axes, which are rotated 45 degrees from each of the main ones. The little masking tape flag on the spolette is used to keep track of the axes as the pasting progresses.

Don’t worry if this is not immediately clear. I lay awake for a bit on a couple of nights visualizing all of this until the light went on inside my head. The purpose of this system is to rotate the “poles” of the layers of paper, so that the final, consolidated wrap of paper has a consistent thickness and strength.

As seen in the above photos, there are open spaces left at the north and south “poles” left after applying the 9″ strips, and these poles are covered with torn strips of paper.

Each roll of strips is sufficient for one axis application, which produces 2 layers of paper on the shell since the strips are lapped by half over each other as they are applied. So, the 4 rolls are good for the first 4 axes, or 8 layers of paper.

As I apply successive layers of the paper strips, I keep the shell nice and wet with the paste, by applying a bit with the paint brush and smearing it around with my hands.

After applying the first 12 sheets/4 rolls/4 axes/8 layers of paper to the first shell, I place it in the drying chamber, with the shell resting on two strips of wood which lie across one of the drying screens. (The shells may be too heavy to rest directly on the screen, and I don’t want them sticking to it.)

While the first shell is drying a bit, I apply the first 8 layers to the second shell. The first shell has taken about an hour to paste, and it dries for an hour while I’m pasting the second shell. Once this is accomplished, I switch the shells in the dryer and make the second 8-layer application to the first shell, then switch them again, and apply the final 8 layers to the second shell. Now I have 16 layers of pasted paper on each shell.

Sometimes, if I’m getting fancy, I apply a few drops of red or green food coloring on the shell as I’m applying the last layers of pasted paper. This results in uniquely colored shells.

Note: One alternative method for pasting the shells is to use gummed, kraft-paper tape, and a tape wetting/dispensing machine. The tape would be applied to the shells in similar lengths and fashion as the pasted paper above. I like to use 1-1/4″ wide, 35-40# tape on 8″ shells.

The next and final chapter in this series will detail Sunday’s lifting and leadering of the two shells. Then we can take them out to the field and put ‘em up into the air!

Till then, Stay Green,

Ned

Firework Shells in 2-1/2 Days – Part 3 is a post from: Confessions of a Fireworks Man