6squirrels Posted February 22, 2012 Share Posted February 22, 2012 Just so no one gets the wrong idea, I don't plan on making flash powder (I see a lot of newbies get yelled at for flash questions, so I'm kind of nervous for posting this), but I do have an interest in chemistry, so I was hoping someone could answer these couple of conceptual questions. Here goes! When flash comps are mentioned, they are made of KClO4 and dark Al (right?), in a ratio. The two that I've seen most commonly referenced are 50/50 and 70/30. I assume the oxidizer is listed first, as the 70 in the latter ratio? Second, I've heard that 70/30 is more dangerous than 50/50. Why is that? Chemically, what happens when the ratio is changed? All I can think of is that with more oxidizer added, more fuel is allowed to burn producing a higher gas/energy output. If this is true, wouldn't that mean with less oxidizer there's just some wasted Al sitting in the comp that doesn't get burned off? Which leads to my next question, is there a stoichiometrically "perfect" ratio of KClO4 to Al? And if there was, would it be more dangerous to use? Link to comment Share on other sites More sharing options...
Mumbles Posted February 22, 2012 Share Posted February 22, 2012 In the ratios you mention, yes 70 is the potassium perchlorate. For 50:50, well, it doesn't actually matter. For what it's worth, I haven't ever really heard of anyone actually using a formula like that. It'd be more expensive and lower performing. You might be thinking of a different mixture all together. I think some of the crappier, but more OTC formulas use that ratio. A perfectly balanced formula is about 66:34. I don't think it'd be noticeably any more dangerous. Whether it be through experiment, personal preference, or cost 70/30 has become the industry standard. Link to comment Share on other sites More sharing options...
Potassiumchlorate Posted February 22, 2012 Share Posted February 22, 2012 There are 50:50 compositions but not with potassium perchlorate and aluminium. It would only be a waste of money. Link to comment Share on other sites More sharing options...
californiapyro Posted February 22, 2012 Share Posted February 22, 2012 maybe that's the ratio for magnesium:perc? http://www.youtube.com/watch?v=YBhH6dQF5V8 first one is kno3:mg and second is kperc:mg Link to comment Share on other sites More sharing options...
Potassiumchlorate Posted February 22, 2012 Share Posted February 22, 2012 Yes. When you use Mg as the fuel, over-fueling will make the flash much brighter, as oxygen from the air will burn the excessive Mg. Link to comment Share on other sites More sharing options...
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