ballmill Posted January 27, 2013 Posted January 27, 2013 I've been experimenting with magnesium chips and turnings mixed with potassium nitrate, and a few with potassium perchlorate to make some fountains. So far my tests have been chips mixed in with an oxidizer in a paper cup left in a loose state. My result was a large reaction of a very bright flame but burned out in a matter of a second. I'd like to try slowing down the burn time by compressing the mixture in a tube more, perhaps by lightly ramming. Does this pose a safety risk or how else can I acheive a more consolidated fountain?
Seymour Posted January 27, 2013 Posted January 27, 2013 (edited) Generally spark producing fountains are based on an easily consolidated and reliable burning base mix (often Black powder based, but can also be other mixes, such as colours) with a spark producing metal added to this. The base mix does not need too be nearly as fierce, fast and clean burning as lift grade powder, and sometimes it is over fueled. Simply screening together the ingredients for black powder after crudely powdering them, and perhaps adding 10% charcoal and 15-20% metal powder will get good results so long as the spark producing metal is suitable in chemical properties and particle size. If you want to improve the niceness of working with the stuff, you can simply dampen, granulate and dry, or add wax or oil or petroleum jelly (usually aided by dissolving them in a hydrocarbon solvent which after mixing is dried off) and cut down the dustiness. Magnesium needs to be coarser than most metal powders to produce good sparks and if untreated will be very prone to degradation due to corrosion, but while not as ideal as, say, Titanium, you can produce a nice effect with it. Mixtures of metals and oxidisers alone tend to consume a lot of the potentially spark producing metal before it gets a chance to get out of the tube at all, have an un necessarily high temperature, leading to tubes failing earlier, are, as you have found out or predicted, harder to consolidate well, and are in my experience much more prone to have erratic burn speed and even just blow up, than traditional fountain compositions. Especially with Magnesium, you run a high risk of boiling all the excess Mg in the flame giving you a rather nice flare, but poor as a spark producer. Edited January 27, 2013 by Seymour
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