kdmoen@watcgl.UUCP (Doug Moen) (04/12/85)
I've enjoyed reading the discussion on 'blowing things up'. I spent a fair bit of time during high school experimenting with pyrotechnics. I learned quite a bit about chemistry and the art of making fireworks, and managed to escape suffering serious injury in the process. Nitrogen Triiodide: I first learned about this by reading "Farnhams Freehold", by Robert Heinlein, believe it or not. If you want to make some, I would recommend mixing tincture of iodine (from the drugstore) with clear ammonia solution, and filtering the result. The materials are readily available, and the yield is low enough that you won't inadvertently blow your hand off the first time around. Since NI3 is a powerful, shock-sensitive explosive, you don't want to mix up too much at one time. The rule of thumb that I learned is that the explosive power of an exposive is proportional to the *cube* of the weight. I.e., 2 grams is 8 times as powerful as 1 gram, 3 grams is 27 times as powerful, etc. Potassium Chlorate and Red Phosphorus: As has already been mentioned, this stuff is really dangerous. I've never mixed this myself; I learned about it from a friend of mine who discovered its properties by accident. He was mixing a few grams of it in a paper cup with a screwdriver. It was fortunate that he wasn't using a glass or metal container, and that he was outside on soft grass. The explosion blew him about a yard, and he escaped serious injury. If you are going to experiment with new firework compositions, it really helps to know what combinations are too dangerous to try. I was fortunate to find a handy book called "The Hazardous Chemicals Handbook", which lists a large number of common industrial chemicals, giving their properties, what not to mix them with, antidotes, etc. Ammonium Nitrate and Zinc Dust: I had more accidents with this mixture than anything else, which makes it all the more surprising that I got the recipe from a book of chemistry experiments for children. NH4NO3 + Zn catches fire and burns, producing lots of white smoke, when you add water. The catch is that NH4NO3 is quite hygroscopic, meaning that it absorbs moisture from the air. I once burned my hand when the stuff caught fire in the mixing bowl (it was a humid day). The second accident occurred after I had placed a quantity of the mixture in a small glass bottle with a metal screw cap. Once again, moisture in the air ignited the mixture, causing the bottle to explode and droplets of molten reaction mixture to be sprayed all over the room. hcrvx1!tracy (who was standing beside me) took the brunt of the explosion, and got spattered with molten goop. If he hadn't been wearing glasses, it's quite possible he would have been blinded. As it was, the scars healed in a few weeks. We were both incredibly lucky to not be hit by flying glass shrapnel. There is still a crater in the ceiling of the basement. General Safety Tips: - Don't use anything but paper and cardboard for mixing, storing, and constructing fireworks. Glass and metal shrapnel can be harmful to your health. - Wear safety goggles. - Work with small quantities, and use the stuff immediately, don't store it. - Know your materials. A book like "Hazardous Chemicals Handbook", and a general knowledge of chemistry can help you avoid unreasonably dangerous mixtures. - Don't fuck around with high explosives. Doug Moen University of Waterloo Computer Graphics Lab