you take a pack of metal sparklers(or a couple of packs, depending on the size of the explosion) and put them together and tape them really tite with electritions tape, a couple of layers, and leave one of the tips of the sparklers out above the rest about an inch and a half, you should tape all of thesparkler stuff, all the way up to the top of the sparkers. then light the sparkler that is higher than the rest and get the hell away.