22 replies to this topic

[pyrotechnist]

I am just wondering if anyone knows a formula that will replicate the firefly stars at the end of this video that just seem to glow and move around slowly.

Firefly shell

[Mortartube]

http://www.skylighte...works-stars.asp

may be helpful to you.

[pyrotechnist]

Thank you for the link Mortartube, it does seem though that them stars just move gently while glowing but do not flicker or flash. Maybe his effect is slightly different or I haven't seen real firefly stars .

[maxman]

The key to good firefly is barium sulfate.

[pyrotechnist]

The key to good firefly is barium sulfate.

Any firefly formulas that you could list using Barium Sulfate?

[maxman]

Try


50 kn03
45 Charcoal
5 Sulphur
+5 Dextrin
+7 Barium sulfate
+ 5 Firefly Al 10-12 mesh


Works very well.

[pyrotrev]

I couldn't view the Youtube video (why do they keep on changing the ******** Flash player?), but having made loads of Firefly comps, I can say that they don't move, but just flash and twinkle, different mixes give differing densities and size of flash. If they're moving it's more likely to be a falling leaves or fish type effect

[pyrotechnist]

I will describe the stars to you then, at first they are like a thick gold with silver but when the gold diminishes the silver just stays behind but seems to very slowly drift in random directions while gently floating down. Maybe it was coarse aluminum and the wind was blowing it etc I ain't to sure but I love the effect as it does look like tiny flying fish that last for ages or real firefly's, very cool effect. The shell was called a Beehive shell and used both firefly stars and flying fish (which wiggled out at the beginning before you could see the full effect of the silver sparks moving around).

It could be that the stars were firefly - some type of bright self propelled micro star.

[Arthur Brown]

As well as the compound, there is the physical structure of the device to consider. As they have a random track they must have some form of internal propulsion, and as they start at height they must have a lift mechanism. I'm thinking of either an insert cup with time fuse, or a shell case, containing very small tubes of compound like very small stickless rockets. Could even be short lengths of fuse with one end primed and the other glued over, as a micro rocket.

[pyrotechnist]

As well as the compound, there is the physical structure of the device to consider. As they have a random track they must have some form of internal propulsion, and as they start at height they must have a lift mechanism. I'm thinking of either an insert cup with time fuse, or a shell case, containing very small tubes of compound like very small stickless rockets. Could even be short lengths of fuse with one end primed and the other glued over, as a micro rocket.

I see what you mean but wouldn't this do the same effect as the flying fish shown at the beginning of the video? or if they are very small and use slow propulsion then you may get the small moving dots as can be seen at the end of the video. Failing that could it be coarse aluminum that has not flickered etc and is just being blown about by the wind?

[Mortartube]

I think you will find that the silver is simply flake Al, by the time the gold part of the star has burnt out, you have tiny pieces of incandescent Al hanging in the air subject to the smallest movement by the wind.

If you watch the video carefully, you will notice that the camera zooms in on the silver sparks at the end giving the appearance of movement. This movement will not happen in a firefly mix to the extent you may believe it is here. It is the camera zoom and not the composition that suggests such a large movement. The sparks are just drifting on the breeze.

Why don't you just ask the guy on the Youtube comments section what formula he used for the firefly stars?

Edited by Mortartube, 12 October 2008 - 10:12 AM.

[pyrotechnist]

Ok then thought it may have been the wind, would be great if you could achieve that effect via formula instead of natural breeze. I may pop him a comment and find out.

[cooperman435]

After watching it again the camera actually zooms out after the break confirming the silver swimming stars are indeed propelled by their own means.

The silver stars are also burning at the same time but in different trajectories than the charcoal stars so have to be completely different inserts to them.

[paul]

Try


50 kn03
45 Charcoal
5 Sulphur
+5 Dextrin
+7 Barium sulfate
+ 5 Firefly Al 10-12 mesh


Works very well.

Got 300g of that stuff in the mill (sans the Al of course).
Gonna make 1" comets from it and let you know!

[pyrotechnist]

I wonder what formula them stars use. They do look self propelled and looking at the video again I can see that they are separate to the initial gold stairs. They make a beautiful effect.