Microjet Stars - Using Potassium Perchlorate
From The Best of AFN III:
After competing in the 1990 PGI aerial competition, I've been asked by some of my friends to explain the principles and how-to's of a microjet star. After many hours testing, failing, and retesting, I finally came up with an idea based on the popular go-getter.
The first time I saw one of these, I was overwhelmed with excitement and headed back to the lab to try to make my own. Making a standard cylinder shell loaded with go-getters was quite simple since they lined up neatly against the shell wall, but you are limited as to how many rows will fit per shell.
Thus came the birth of the microjet. Using a different construction method, I cut the overall size by 80% with burn time almost equal to a full size go-getter. The void I felt created by a go-getter shell was suddenly gone, and a full, almost symmetrical pattern was achieved by tripling the amount of stars in the shell. Still not completely satisfied, I thought a little more enhancement might be needed for a more interesting effect. Since the size of the jet is so small, it could be used as a core in a round star. Here's how I do it.
First, I roll some 3/8" diameter tubes with 2 turns of 40 lb. Kraft paper, about 8" long. After drying them, I cut them into 3/8" lengths. Next I cut a few 1 foot pieces of medium speed thermolite and dip them in a thin slurry consisting of nitrocellulose lacquer, Meal D, and acetone to put a nice thin coat to keep them from crumbling when being cut.
I then cut the thermolite in lengths slightly longer than the 3/8" tubes to be used later. Next I mix my composition in a small air-tight container and knead it into a tennis ball size dough ball.
NOTE: You can also use blackmatch or silver flying fish fuse instead of thermolite.
Since the formula I use is so Parlon rich, it is easy to mold and press into the precut tubes. After pressing 15 or 20 tubes (with forefinger and thumb) I insert a piece of thermolite in the center, repeating the process until done.
Drying time is usually 1 or 2 days, depending on the weather. When they're dry, I gather them up into a tight bunch with the thermolite end up, and using a paint brush smear a hot igniter slurry over the tops. When dry I turn them over and coat the under side with a thick jelly of N/C in acetone to slow or stop the ignition of the bottom side of the jet.
Now I mix a batch of White Aluminum Streamer comp., and in a large round bottom bowl I start coating the jets with streamer composition. Stars were rolled 3/4" in diameter and primed with a hot mix, Meal D prime. The end result is a star which leaves a long silver/white tail, and at the end, zips across the sky in a different color. Here are some formulas I've used.
NOTE: When rolling stars, I use a non-aqueous system. No water should touch the jets due to the presence of magnesium. (Latex gloves, face shield, and respiratory protection are minimum personal protection. Flash point of acetone is -4 degrees F, with very high evaporation rate, factors which favor the likelihood of dangerous vapors around the work area).RED MICROJET
|Magnesium 100 mesh *||17|
|Aluminum, spheroid 325 mesh||12|
|Charcoal, air float||5|
|Charcoal, air float||2|