
This isn't terribly practical, but it is a lot of fun to shoot, and it's a good way to get a lot of power out of a CO2 bike tire inflator for little money. The real reason I made it was to prove that it can be done safely and cheaply, and hopefully cut down on the amount of threads in the NIC dedicated to CO2 bike tire inflators. Plus, I had the cannon laying around from a different project.
The gun consists of a 12"X1/2" PVC nipple, capped at one end, with a schrader in the cap, and a 1/2" union on the other end. Part of a 24"X1/2" PVC nipple is screwed into the other side of the union. That's it. A burst disk is inserted into the union, and a mega stefan put in the barrel. I usually use parts of a plastic shopping bag or trash bag for burst disks, with between 2 and 4 layers depending on power needs. Using 2-layer disks, I can get up to 10 shots out of a cartridge, each going at least 110'.