Apr 30, 2012· Pop (Pneumatic) I saw 700R and Cajun Welder's design and liked it more than mine, so I copied them. My original valve setup was a pain. When I switched valve types I decided to just start over. I added a hopper to put the cans in easier. The hopper holds about 1518 cans. I have some talented students and asked one to draw up Heinz Doofenshmirtz from Phineas and Ferb.