Pyrotechnic Formulas For Willow Firework Stars

This was clipped from the Western Pyrotechnic Association's mailing list. It was a reply from Gary Bergman to Kurt Medlin regarding comets and firework stars Gary had made. It's a little choppy, but you can get the gist of it. Thanks Gary and Kurt.

Gary writes to Kurt:

Hi, Kurt,

The 12-inch salami comets were pumped using a standard 1 3/4" Wolter comet pump. When the comets were dry they were wrapped with 2 turns of 1-inch wide 20 lb. Kraft (lightly wheat-pasted), which left 3/8" of comet composition exposed on either end. This step was per your experience on the 8" Gold Willow you had made (I replaced your formula's 80 mesh airfloat charcoal with lampblack) and was to fulfill my desire to make sure that these made it to the ground - hopefully a little above ground level would be better. The basic pyrotechnic formula is (in parts by weight):

Berg's Gold Willow Comet
Potassium Nitrate 36
Airfloat Charcoal 29
Lampblack 14
Sulfur 9
Titanium Sponge 7
Dextrin 5

For the Titanium I mixed -10+20 mesh (64%) and -30+60 (36%). [If you can't get sponge titanium, you can substitute any other form of titanium]. This was all bound with 12% binder solution by weight (75% water and 25% alcohol).

Kurt asked:

My "Mess-Kit Willow" firework stars are 1/2" grid firework stars using the plastic 1/2"X 1/2" light grid as a mold and mashing the firework star composition into the grid laying on a piece of PVC sheeting.

The formula was based on the "Bright Willow" pyrotechnic formula below (parts by weight).

Kurt's Bright Willow Firework Stars
Potassium nitrate 50
Charcoal, Airfloat 15
Lampblack 15
Antimony Sulfide, -325 mesh 9
Sulfur 6
Dextrin 5
Bright Aluminum, 400 mesh 15

In the pyrotechnic formula that you use, you replaced 1/2 the recommended airfloat charcoal with lampblack for your version of "Bright Willow." My love of the willow firework star prompted me to ask about a long-hanging willow pyrotechnic formula. If you will remember the "Bright Willow" pyrotechnic formula that you suggested to me, jokingly, was replacing all the airfloat with equal parts lampblack and bright aluminum, -400 mesh. This was after I first got to know you and I don't know if you wanted me to either "go away" or just see how dedicated a pyro I really was. I remember when you found out that I had actually made it you howled in laughter.

"You actually made that mess." And that is exactly what I named it - "Mess-Kit Willow."

Mess Kit Willow Firework Stars
Potassium Nitrate 50
Lampblack 15
Bright Aluminum 15
Antimony Sulfide, -325 mesh 9
Sulfur 6
Dextrin 5

This is a pyrotechnic formula not to be undertaken by the faint of heart nor a clean freak. It goes EVERYWHERE and then some. But the results are a superior glitter firework star that hangs for along time.

Kurt continues to query...
--That's a big comet and I thought the Mess Kit version had only a moderate burn rate.--

Actually the "Mess Kit" Willow pyrotechnic formula was only used to make the grid firework stars encasing the lone 1 3/4" comet. The comets were 1.75" diameter by 1.75" high cylindrical pumped comets (using a regular size Wolter comet pump) that were placed in concentric rings (16 to a ring) against the casing wall of the shell per Fulcanelli's great articles "Traditional Cylinder Shell Construction" in Pyrotechnica IX (Part 1) and Pyrotechnica XI (Part 2).

The smaller Mess Kit Willow firework stars were placed in with the pulverone (loose) surrounding the Burst core.

Think of 3 rings radiating from the center, (if looking down the inside of the shell from one end).

Center Ring: 2 1/4" diameter is burst (2FA)
Middle Ring: Pulverone/willow firework stars
Outside Ring: Large pumped comets

For anyone wanting to build cylindrical shells, the Pyrotechnica articles are very straightforward and a great reference. I have read them 20+ times and still refer back to them.

I pre-tested the firework stars and comets in 4-inch ball shells. The 4" ball shells were over lifted with extra long time fuse (2") to more closely simulate the breaking height of a 12" shell. It was for reference only to see what the burn time and characteristics were of the comet. The Mess-Kit Willow firework stars were an afterthought to help fill the shell and save valuable rice hull burst, of which I was running low. Glad I tried it. I tried the Mess Kit firework stars before, and it did not light in a hard-breaking shell, and I was going to prime them. Lacking time, prime, and even less time I just threw them in there. Better in my shell as filler than filler for the burn pile. Anyway, the firework stars worked great in the light-breaking shell, which is how willow is supposed to be used.

By the way, I highly recommend "Mess-Kit" Willow firework stars for anyone in manufacturing on a windy day so that you can "share it" with everyone downwind. You're sure to get responses, not all great ones, mind you.

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