One of my twin Uncles was a gunsmith. He showed me how to make firecrackers with paper tubes scavenged from wire coat hangers and pistol powder. Had a lot of fun doing that with him, as well as learning to shoot guns - I was about 11 years old. He also taught me how to do it right - so that I didn't hurt myself or others. We also made a small cannon made out of brass that used wadding - just to get a nice bang. He showed me how to make fuses, and even ordered a 25 ft roll of underwater fuse thru the mail - so that we could make our 'fun' a bit more professional looking.
The biggest charges we made were done with acetylene and oxygen from welding tanks. We would take a plastic sandwich 'baggie' and ring all of the air out of it first. We would carefully get the right mixture out of the acetylene/oxygen tanks and fill half of the baggie - and then tie a knot to close the bag up. We then set the baggie filled with the gas mixture on the pavement and then took turns flicking matches at it from six feet away until someone got lucky. It is amazing to see just a small amount of this gas explode with the same force as a cherry bomb. Much better than the first firecrackers we made.
The biggest charges we made were done with acetylene and oxygen from welding tanks. We would take a plastic sandwich 'baggie' and ring all of the air out of it first. We would carefully get the right mixture out of the acetylene/oxygen tanks and fill half of the baggie - and then tie a knot to close the bag up. We then set the baggie filled with the gas mixture on the pavement and then took turns flicking matches at it from six feet away until someone got lucky. It is amazing to see just a small amount of this gas explode with the same force as a cherry bomb. Much better than the first firecrackers we made.