5 replies to this topic

[MDH]

I kept the "Average user" in mind when making these star compositions. Meaning that making these stars is fairly simple.

Anyways, to the formulas:

Red, Green, Yellow, Pink/Orange
Potassium Perchlorate, 70
Shellac, 10
Parlon, 10
Metallic Carbonate, 20
Dextrin, 3-5
Other Notes: Diaper or screen the components together. Once they are thoroughly mixed, dampen it with water and mix it until it is like a wet dough (not a slurry). Press the composition as a dough onto a flattened piece of wax sheet. Once the composition is dry, bend the wax sheet to granulate the composition.

Now, onto a blue. I tried making blues with the above composition but they came off more as off-lilac. Not a very good colour...

Potassium Perchlorate, 70
Parlon, 10
Copper Sorbate, 20
Dextrin, 3-5
Notes: Same as above. Screen it through a 100 mesh screen until no lumps are visible, which should be easy to tell as copper sorbate has a vividly candy blue colour, then wet it to a dough. Roll it into 3mm stars or granulate it once dry. Leaves a bit of black ash showing an excess of fuel, but the blue colour is at its best with this composition.

And the burst composition for these, which I have mentioned before but has been optimized quite a lot:

Potassium Perchlorate, 60
Potassium Sorbate, 38
Iron Oxide (red), 2
Notes: Crush the potassium sorbate into a fine powder and gently daiper the ingredients together. You could probably granulate it with dextrin but it is not necessary. Adding higher fuel values such as 50-48-2 will actually increase the burn rate significantly and may suit salutes better.
IMPORTANT NOTE: This composition is extremely powerful, much like flash powder in its behavior. Take caution while handling it. Be gentle. It may also be necessary to replace 50% by weight of this composition with green mix to slow it down in smaller devices.

Substituting 50% of the copper sorbate in the blue formula with other chemicals will yield variants of blue such as aquamarine or purple but may also decrease the burn rate.

These stars are good for inserts. I'm producing a star mine of about 20-30 small 3/4" cardboard inserts which will open into hundreds of blue, green, yellow and red stars at apex.

Working on a silver one made from calcium sulfate, aluminum, sulfur and coarse aluminum so watch this thread.

Edited by MDH, 19 October 2009 - 06:14 AM.

[a_bab]

Thanks for the formulas.

What is the burn rate for a star say 3 mm/side (cube)? Do they need a prime?

[MDH]

I would say about anywhere from 1-3 seconds depending on how fine the shellac is - The microstars must have longevity once they burn since I also plan to use these in matrix comets and fountains, where some of the composition may burn up prematurely. The sorbate stars burn quickly.

Do not bother with primes. I find that in bombettes a small layer of these microstars above black powder packed neatly, and also tightly below craft paper allows them to ignite easily.

If you are using it in shells with powerful flash boosters then yes I might recommend priming them with black powder and sprinkling some small amount of sawdust over them.

[a_bab]

So you think colophony would work as a replacement for shellac? What about PVC instead of parlon?

[MDH]

So you think colophony would work as a replacement for shellac? What about PVC instead of parlon?

I don't think so.

Their burning characteristics are too different. PVC has significantly less chlorine.

[MDH]

Ok, here is a (Somewhat) cheap, working silver microstar composition:

Calcium Sulfate, 50
Sulfur, 25
Aluminum Dust (-600), 25
Dextrin, 3
5/3/2 also acceptable ratios, but may be less bright

Calcium sulfate will readily bind the composition but I find that it needs assisting, specifically for when it is being pressed. This composition can be bound with borated water. Dampen until it is a slurry, then pour it over wax or foil sheet. Once the composition is dry, slowly bend the wax sheet to granulate it.

I find these very favourable for fountains and wheels. It produces an effect similar to large magnesium bits without using magnesium, and calcium sulfate is possibly one of the cheapest oxidizers in existence.

These have to be primed for small shells but they don't need to be primed for fountains. Finely granulated enough this will behave as a report composition so do not add stars finer than several millimeters to fountains.