seymour

Considering that every year millions of commercial salutes are slammed out of mortars by lift charges, without this setting them off, I think it's obvious that the sensitivity of some types of good quality flash is low enough for it to be usable without undue worry.

In the context of these safer flash powder options many of the reports of flash powder sensitivity may seem untrue (and this often the case), but when talking about the less safe flash powders they may not be exaggerations. I've heard of Permanganate flash salutes exploding during storage.

While the Maltese have show that even chlorate flash is insensitive enough that you can drop a salute on the ground without worrying, with chlorate mixes I do constantly worry about Ammonium salts... either Ammonium perchlorate, Ammonia based cleaning products, and even nitrate-metal mixes (which can form ammonia), or acidic material, all of which can result in spontaneous explosions. When you combine that possibility with the extreme power of flash powder, the risk becomes very serious. Besides these possibilities of chemical reactions, the fact is KClO3 will be more sensitive than KClO4 if in similar mixes, and as Digger said, there's no need to use KClO3 instead of KClO4. With the single exception of coloured smoke, there is no need for any effect.

So, while this is certainly not the thread to suggest making and using flash powder, I don't think it's a bad idea to repeat that the generally accepted standard flash is based on Potassium perchlorate and Aluminium only, and while the raw power is intense, and it should be treated with great respect, at least one does have to worry about serious contamination issues. The consequences of unwanted ignition are about the worst of any class of pyro mixture, and so all measures to reduce the chances of ignition are highly recommended, the most effective of course is leaving it alone.