My sons and I made one out of PVC pipe. We used hair spray to create the explosion to shoot the projectile. It was great fun to play with and it can shoot far. The big issue is getting the oxygen / hair spray mix right in the explosion chamber, which is why we gave up playing with it. We took it the coast one year on one of our men's trips. It had the potential to send the bait a long way, but the igniting issue made it a problem, as well as having to lug more equipment down to the sea. We used a 100mm drain pipe for the chamber, with a reducer to a 50mm barrel. I bought an igniter from the gas shop, drilled a hole in the combustion chamber to install the igniter. The bottom of the 100mm ignition chamber had a screw on lid. I put a screw through the barrel to stop the bait falling too far down and into the combustion chamber. This thing was like a bazooka / cannon. It mad e a lot of noise. Out projectiles were ice blocks, shaped in a 50mm pipe. absolutely no friction. When we tried it at the coast, we froze the sinker, and bait, together into the 50mm pipe mould, so they just slid onto the barrere. You have to use a coffee grinder reel. When the bait / bullet hits the water, the ice melts, and your bait is out. Great fun!!
