Posted 25 November 2004 - 12:58 PM
D1 glitter is tricky, the Aluminium type and size is very important!
Flake doesn't work very well in it, it basically burns sliver with little delay. Spherical with an tight distribution of sizes is the best. I use commercial -325 mesh spherical Aluminium, Miral brand I believe, I can find the code number if I dig around in the metals box.
The charcoal is also quite important too. My friend used commercial airfloat and found it generates a completely different effect to my pine charcoal. Willow effects the delay too much IMO, just use cheap and nasty charcoal, but low ash. High ash content tends to inhibit the flash reaction. I haven't tried lampblack yet.
Another problem is that D1 is quite hygroscopic. On a damp night you can find your D1 stars burning to the ground if you leave the bag open to the air for a few hours. I have observed this in my friend's D1 stars, but not mine, so it might be related to his charcoal feedstock or pirming technique. We use the same Aluminium.
The wet reaction is an issue too. I am not 100% sure I fully understand the conditions that can ruin a batch of glitter by over-dampening yet. I've never experenced it with D1, but Fish and Winokur glitters containing Iron Oxide are almost always ruined them if you add more than about 4-5% water. I oven dried a batch of Winokur Salt glitter, and it worked quite well... Strange! D1 is definately more drossy after wetting, producing larger, longer delayed flashes, but less in total number.
The Boric acid also seems to makes a difference, but I'd need to shoot two stars side by side to prove that beyond observations I've collected over a few batches with and without it.
I also use Tiranti Al. I always make 100g at a time including the boric acid. I mill everything for about an hr before screening in the Al. I then pump them into 6mm stars for use in my small shells or 3/8" for my 1/2" candles.
