And now for the interesting bits:
My Cannon, in all its primer and glue stained glory
All of the pipe is PN12-PN18 (which means that it is rated to at least 170psi) but I usually only go up to about 120psi just to be on the safe side and also to try to preserve my piston from damage. It's got an advanced ball valve as the pilot valve and the piston seals on a 4cm diameter section of pipe. It is also quite ergonomic (for left handed people) because you can push your shoulder into the "t" and let it sit over your shoulder with very little effort and from there you can easily reach the trigger.
The whole trigger mechanism looks pretty flimsy and I know that I've used dreaded Zip Ties to tie it on but I really can't be bothered to do it properly so for now I will say that it is for easy disassembly. To actuate the ball valve, it has a spring and some rubber bands to pull on a length of fishing line.
The piston is also pretty ghetto because it was made out of the lid of a spray can and some fibreglass. To make sure that the lid doesn't blow out under pressure, the fibreglass extends into the inside of the lid to reinforce it.
As part of the bumper for the piston I've shoved a bit of foam into the piston and inside the cannon there is some more cushioning.
Here it is with its golf ball barrel on. It also has a marble barrel and slightly bigger sized one for miscellaneous projectiles.
Here are some fake golf balls that I made from a mould of a golf ball and glued together with some of the leftover fibreglass resin. The one on the right looks a bit different because I decided to spread some resin around it to make sure it doesn't disintegrate in the barrel because, for some strange reason, lots of things tend to disintegrate in the barrel....
Well that's pretty much it for now untill I can get some damage pics and for that to happen I'm going to need to find some more golf balls and marbles to fire which might take a while.
