Air does not make boom.
Where do you guys get cheap exploding targets?
Al, oxidizer done. just have to have the right oxidizer for low energy impacts to set it off. Dangerous stuff for fools. I started at 8 years old in the 1960's with a chemistry set I got for christmas, amazing what you could do with one and a public library for research. By my teens I used to make some crazy sensitive contact explosives, less than a gram at a time, paint a piece of hamburger, set it out to dry and watch flies blow themselves to bits. Even made plastics almost as good as C4/semtex, high molar concentration acids used to be so simple to buy. Gave all that up in my early 20's, mortality, law, common sense creeping in and such...Can't tell you here how I make my own targets but I'll answer PM's.