15 replies to this topic

[The Swedish Scientist]

Hi, I am looking for coloured firefly star compositions, please post anything you have. (I'm keeping it short cause nobody really reads the full-screen posts.)

[Creepin_pyro]

What exactly do you mean by coloured firefly? What colour are you looking for?

[matthew]

you can find some comp from www.cannonfuse.com

[Creepin_pyro]

you can find some comp from www.cannonfuse.com

I don't see any coloured firefly there...

[matthew]

there are firefly #1,#2,#3

[Creepin_pyro]

I was of the understanding that metallic fire-dust stars are not generally reffered to as being coloured. It's confusing asking for coloured fire-dust compositions, because they don't exist - please correct me if I'm wrong...

The only way I know of producing a coloured star with a fire-dust tail would be to make a stacked comet, or cavity star.

[Bonny]

I've mixed a batch of Firefly #3 stars from the formula below, but still need to add the Al and coarse C. I don't actually have any fiirefly Al, but I was thinking of using a mixture of some Al grades. I have 20,40,60(I think) as well as 250 spherical. My main question however is: how do I prime these stars? Do they need step priming?



Firefly #1
Source: rec.pyrotechnics archive. Posted by Eric Eisack.
Comments:
Preparation: Aluminum is large flake. It was sieved through a windowscreen. This gives about 30 mesh powder.

Potassium nitrate.................................50
Charcoal,air float................................29
Charcoal, 80 mesh.................................10.5
Sulfur............................................6
Aluminum (large flake)............................4.5
Dextrin or CMC....................................+5 or +1

Firefly #2
Source: rec.pyrotechnics archive. Posted by Dan Bucciano.
Comments: Can also be used as rocket propellant: Mix the chemicals, dampen, and granulate through a 20 mesh screen and dry. Use +3% by weight as a tail effect. Once you have passed the top core of the rocket by 1/2 inch, you may ram 100% firefly formula the rest of the way. You will end up with a beautiful long trailing tail of firefly.
Preparation:

Potassium Nitrate.................................47
Air Float Charcoal................................33
Antimony tri-sulfide..............................5.8
Aluminum (400 mesh,12 micron, spherical)..........4.2
Sulfur............................................4.7
Dextrin...........................................5.2

Firefly #3
Source: PML Digest 391, post by L.Niksch <LNiksch@aol.com. This formula is provided with the "firefly aluminum" from Skylighter.
Comments:
Preparation: Ball mill potassium nitrate, Air Float charcoal, sulfur and Dextrin together for 1 hour. Then add the 36 mesh Charcoal and firefly aluminum and mix with a spoon. Add water to make a dough mix and cut with a knife into 3/8" cut stars. Separate stars and dry for 3-4 days. The effect is a long tiger tail going up and firefly sparkles coming down. Larger stars take longer to dry, and a damp star produces very little firefly effect.

Potassium nitrate.................................49
Charcoal, air float...............................29
Charcoal, 36 Mesh.................................11
Sulfur............................................9
Dextrin...........................................10
Aluminum, firefly.................................5

[Pyro-pal]

I had a batch of firefly create the longest drawn out reaction with atmospheric oxygen that I have ever seen. This was you’re basic 80 mesh charcoal recipe except 5% Barium nitrate was substituted along with using thin wheat paste as the binder. I found after trial and error firefly stars malfunction if cut bigger than 10mm (.393) so 3/8” is good. The stars need to heat up fast so projecting them at maximum velocity from an end breaking “aerial mine” type canister shell is best to produce the drawn out effect.

Edited by Pyro-pal, 04 February 2008 - 08:38 PM.

[lavenatti]

It's unlikely you'll need any prime, they should light easily. If you do prime, meal should be sufficient.

That second formula you listed looks more like a glitter than a firefly with the antimony trisulfide added. Shimizu added barium sulfate to a firefly formula, I believe you'll get better flashes with the added sulfate.

Shimizu Firefly #5
KNO3 50
Charcoal (AF) 45
Barium Sulfate 7
Sulfur 5
Wheat paste 5
10-12 mesh Al 4.6

[Bonny]

I finished mixing the comp (#3) last night. For the 5 g of Firefly Al I used 2g (+20-40) and 2g (+40-60) homemade Al and 1 g 250 sph. I make into stars and maybe a 1" comet in the next day or so and add a layer of meal prime. Should I add some boric acid to the water/alcohol?

[lavenatti]

Sure, it's a comp containing aluminum and a nitrate so it's a good idea. Even though the aluminum is a large flake there's no reason not to take the precaution.

[pyrotrev]

I've played with firefly a fair bit, and never found the need to use boric acid, but I was using seriously coarse (10...30 mesh) ali. Neither did I find the need to do much priming with wheat paste binder unless you're breaking the shell really hard.

[MDH]

It's unlikely you'll need any prime, they should light easily. If you do prime, meal should be sufficient.

That second formula you listed looks more like a glitter than a firefly with the antimony trisulfide added. Shimizu added barium sulfate to a firefly formula, I believe you'll get better flashes with the added sulfate.

Shimizu Firefly #5
KNO3 50
Charcoal (AF) 45
Barium Sulfate 7
Sulfur 5
Wheat paste 5
10-12 mesh Al 4.6

The sulfate is actually there as a delay agent to just about everything in the composition. If you make a black powder fountain with 40 grams, and put a few grams of calcium sulfate and just a gram or two of aluminum it, it will all react once the fountain has gotten hot enough, and all of the composition will burst out of the top of the tube.

[Pyro-pal]

Here’s a video of a longer drawn out firefly effect that looks more like a cascade:
http://video.google....5...45286&hl=en
Excuse the grainy image.
----
Compare with a firefly effect that sparsely twinkles:
http://www.youtube.c...feature=related

[anacronismo]

Here’s a video of a longer drawn out firefly effect that looks more like a cascade:
http://video.google....5...45286&hl=en
Excuse the grainy image.

Pyro-pal: you know the formula of this effect; like a cascade ?