Microjet Stars – Using Potassium Perchlorate

Written by Rick Slemmer

Topics: How to Make Fireworks

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

Potassium perchlorate 25
Strontium nitrate 25
Parlon 30
Magnesium 100 mesh * 17
Red gum 3

 You can replace the Magnesium with Mg/Al -200 mesh.

ALUMINUM STREAMER

Potassium nitrate 51
Aluminum, spheroid 325 mesh 12
Magnalium, 50/50 8
Titanium, coarse 8
Charcoal, air float 5
Red gum 5

 

HOT IGNITER

Potassium perchlorate 65
Silicon 20
Red gum 10
Sulfur 5
Charcoal, air float 2

(I mix 2 to 1 with Meal D)

Questions, Comments? Have you made these before? Tell us of your successes and/or questions below.

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How to Get 22% Off Your Microjet Stars plus Titanium Dihydride:

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If you have any questions whatsoever, then by all means call or email us.

Now, git outside and light something!

Harry Gilliam
Chief Cook & Bottle Washer

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23 Comments For This Post I'd Love to Hear Yours!

  1. Elmer Hamlett says:

    I see comments about using water mixed with magnesium and it sounds like it shouldn’t be done? Please explain this! And where are the answers to all of these questions? Thanks!

    • Dan Creagan says:

      Elmer,

      Water and magnesium react to form, among other things, magnesium oxide. The reaction is quick with finer mesh Mg so there is a lot of heat released. In most of our pyro mixes we have an oxidizer and that, combined with the rapidly deteriorating Mg can cause an oxygen fueled thermal runaway and eventually ignition (in some cases it can happen in moments).

      Never wet compositions that have magnesium.

  2. Jimbo says:

    Flying fish fuse might be a good start.

  3. No Thermolite? Or, don’t want to waste your hoard of unobtanium on stars?

    Make the stars without the Thermolite. While still wet, push a toothpick into them an make a 1/8″ hole. When dry, drop a piece of black match in the hole and plaster it in with NC/BP slurry 50/50. Let dry.

    I use a similar setup with my own version of the class C product called a ‘Hot Head’. Same formulas (essentially) only rolled into long 3/4″ thick worms and cut at 3″ intervals. Wrap in pasted paper and put on the end of a 3/4″ tube filled with pixie dust. Fuse from 3/4″ tube is black match. Stick in ground (can tape a skewer to the side as a stake). You get a very bright ground gerb that is mellow and pleasing… until it lights the pixie dust.

  4. Elmer Hamlett says:

    NOTE: When rolling stars, I use a non-aqueous system. No water should touch the jets due to the presence of magnesium SO why is water not to be used with Magnesium in your formula?

  5. Milton Baker says:

    Was not able to print instructions for micro-stars?

  6. Gary Moore says:

    Yes Dan Thames, I think has a formulas on his website.

  7. Steve says:

    I don’t even know what Thermolite IS…

    And, Google search insists it is an insulating fabric, like thinsulate, or a window.

    • Harry Gilliam says:

      Steve, “Thermalite” was a metal-cored, very hot-burning fuse that was around for a few years. No longer manufactured I believe. Note that spelling is slightly different from what you were using. –Harry

      • Wm Osburn says:

        Harry,

        Thanks for the explanation. I had the question originally. But now that I know what it is, I found out how to make it at the following site:

        http://www.brianredmond.net/dwilliams/thermalite/thermalite.html

        Looks pretty hairy and the least little bit of water in the acetone could react with the magnesium. Think I will look for easier methods before I try this method.

        Thanks!

        MagicBill

        • Dan Creagan says:

          MagicBill,

          Try the black match in the hole – pasted in with a BP/NC slurry. It works fine. No need for Thermalite – a substitute can be made but I would doubt it would be time effective. After all, we’re just talking about stars and you have to make a lot of them to get an effect.

  8. Shaggyman says:

    “medium speed thermolite”
    Actual Thermolite is rare- I know I don’t have any…
    Substitutions?

  9. Wm Osburn says:

    Neat article.
    But what is thermolite?
    And how do I make it?

    I need more info if I’m going to try this out.

    MagicBill

  10. paul pinciak says:

    Hi, Again,
    Question?
    On your formula breakdown, are the numbers parts to parts or in grams of chems?

    • Alan says:

      The answer is: Yes – either parts, or grams. If you want more, use larger units, or less, use smaller units. These are usually parts, but proportions are proportions regardless of unit of measurement. You could use pounds or tons if you are rich. THAT wound be sparkly…

  11. paul pinciak says:

    Hi,
    This sounds like a fantastic effect that I can’t wait to try

  12. mark maddalla says:

    how do you get the Al steamer to stick to the microstars to roll a star
    without using water/alc spray ?

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