Funny thing about explosives, the knowledge isn't hard to get. A kid in my old school a few years before I got there apparently made tri nitro benzene out of things nicked from school. That', I case you didn't study organic chemistry at school, is a more unstable and difficult chemical to make than the fairly similar tri nitro toluene. It's a bigger bang too apparently. If you don't manage to blow yourself up making it over 2 or weeks at at temperatures and pressures.
Out of safety considerations we just stuck with gunpowder. We did not afterall want to blow things up badly just make a bright, colourful display inside a wall of of oak lockers.