2 replies to this topic

[firework004]

when potassium nitrate and aluminium somtimes along with sulfur and dextrine for a white star. what kind of aluminium is used bright, dark, normal small micron?? thanks

[paul]

Generally speaking: You can use alot of al types here, but the coarser it gets the harder it´ll be to start the reaction.

KNO3/Al stars (cores) can be incredible hard to ignite, even if 325 bright flake is used. So you have to find a formula which ignits more easily. Sulfur is a step into the right direction.

I tried a few KNO3/Al/S star mixtures with 63-50µ standard aluminium (the stuff used as a epoxy filler) and these were INCREDIBLE hard to ignite after they dried completely.
So a step prime is needed in most cases. First the core, then a layer 60/40 star composition/blackpowder and after that a prime layer.


EDIT: I´d use an water/alcohol mixture for binding then. Maybe 70/30 and a bit boric acid as only
KNO3 and Al are present without any buffer.

Edited by paul, 05 April 2007 - 06:53 AM.

[hst45]

My favorite glitter compound is Winokur #6, which used <325 mesh flake aluminum. The compound also contains charcoal and sulfur, so I suspect these aid in ignition. With this compound in a cut star, no prime is needed, although I usually dust them in BP greenmeal to be sure. It also makes a wonderful comet. The formula I use is:

KNO3 53
Antimony Trisulfide 16
charcoal (I use relatively coarse hardwood) 13
Sulfur 9
Aluminum flake, <325 mesh 4.5
dextrin 4.5
boric acid +1