Lentamentalisk wrote:btw, where would I get large mesh KNO<sub>3</sub>? any suggestions of garden supplies etc. that would have that?
If you can find stump remover, it is probably the easiest option. However, in Canada where I live, KNO<sub>3</sub> containing stump remover has been banned, and KNO<sub>3</sub> is a pretty stringently regulated chemical here these days. I managed to obtain a few 500 gram containers of stump remover for $12 each from the local True-Ripoff hardware store a couple years ago, but according to the owners, that was the last of the stock they will ever have. My friends and I obtained endless hours of entertainment from those containers, with both the smoke bombs and the black powder that we (I) made using the potassium nitrate.
If you live in the USA, it might still be on hardware store shelves.
Alternatively, it is used frequently as a dry fertilizer in planted tank aquariums and hydroponics, so almost any hydroponics supply store in both the USA and Canada will have it for a fraction of the price of stump remover. A store known as "Atlantis Hydroponics", based in the USA, sold 50lb bags of pure potassium nitrate for $20 back in 2004, but I'm not sure if they still do. Common hydroponics prices for small quantities will be around $2-$4/lb.
Hydroponic and stump remover KNO<sub>3</sub> generally is not technical grade (>99% purity), but it is damn close, generally around 98-99% pure, which is more than adequate for any pyrotechnic use.