Pneumatic Cannon 1/2 inch

Step 3 Compression Chambers

'The chambers are designed to gather as much air as they can to build up pressure and release it through the valve all at the same time. The wider and longer the chamber, the more force it releases and can contain.'

First, Gather the last length of PVC you have (hopefully it's in one long pipe) and cut 2 equal pieces using all of the 1 inch piping. (These are the Chambers.)