Quite possibly the cheapest, most stable, most easily made and most easily acquired explosive that an average joe, wanting to blowing something up for the sake of fun, can make. Flash powder is commonly used in M80s, silver salutes, firecrackers, and cherry bombs as well as large scale salutes seen in professional fireworks shows. It consists of two components: finly powdered aluminum (2 micron), and potassium perchlorate mixed in a ratio of 3 parts aluminum to 7 parts potassium perchlorate by weight. Both of these components are perfectly legal to purchase, and can be purchased online by anyone, of any age, who has a credit card. The aluminum must be a very finly powdered flake style usually sold under the name indian black or german blackhead. It can be bought from eBay. The potassium perchlorate can be found at any number of internet suppliers. 1 pound of flash powder can be made for only around $20.00 US, although a typical device like an M80 contains only 5 grams (1 lb = 454 grams). The power of flash powder can be increased significantly by adding additives such as: sulfur, antimony sulfide or just simply black powder in small amounts, typically 8-9 parts flash powder to 1-2 parts additive. This however, decreases the stability and could cause spontaneous ignition especially if the additive is not free of acid. Flash powder is scientifically designated a low order explosive meaning it burns quickly producing a great deal of energy in a small about of time. Legally it is classified as a high explosive. Due to the ultra high burning temperature of aluminum the rate of burning in flash powder actually reaches the speed of sound causing a detonation like a high explosive. This requires a critical mass of 50 grams in order for the flame front to acheive the speed of sound. For this reason quantities of flash powder in excess of 50 g do not need to be confined within a container in order to explode.
Flash powder is a powder comprised of Potassium Perchlorate and Aluminum Powder. It's called flash powder for it's rapid expansion, it literally flashes out of existence with a bright flash of light. Flash powder is used in most exploding firecrackers but in small amounts. The legal limit for the U.S. is 50 milligrams, M-80s and other such types of firecrackers contained the same powder but in larger quantities. M-80s usually contained 7 grams of flash powder. Flash powder is so powerful that in larger amounts it will explode upon ignition without the need for a shell for gasses to build up in.
"Wow! That flash powder really makes for good firecrackers, it just ripped the hood of that car off!"
" I know, good thing we used 4oz of it, I wounder what 8oz would do?"