Pipe Cannon Plans
A simple cannon can be made from a thick pipe by almost anyone. The only difficult part is finding a pipe that is extremely smooth on its interior. This is absolutely necessary; otherwise, the projectile may jam. Copper or aluminum piping is usually smooth enough, but it must also be extremely thick to withstand the pressure developed by the expanding hot gasses in a cannon.
If one uses a projectile such as a CO2 cartridge, since such a projectile can be made to explode, a pipe that is about 1.5 – 2 feet long is ideal. Such a pipe MUST have walls that are at least 1/3 to 1/2 an inch thick, and be very smooth on the interior.
Check out some of these improvised pipe cannon plans.