Spudtech Forum

I just built my first pneumatic cannon. When I try to air it up, the air goes straight through the valve and out the barrel. I used a rainbird CP-100 valve and modified it with a blowgun. What did I do wrong?

My first guess would be that you have the valve backwards or there is a leak somewhere.
Orbit valves have arrows that indicate flow direction. I think your rainbird valve may also have arrows.
If it is installed in the correct direction then there must be a leak somewhere.
Did you remove the solonoid? If so you need to be sure to plug the hole with epoxy or something otherwise the valve will not close properly.