SpudFiles

The barrel is a 75 mm OD PP drain pipe. I am NOT afraid it will explode; that plastic is really tough, much better than PVC. Only problem is, it is nearly impossible to cement

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Wrong..

The barrel will desintegrate at 10 bar.
I
Trust me.I 've blown up a nearly identical cannon at 9, wich had a 75 mm pressure rated barrel.
Because of ice, I know, but drainpipe can NOT take that kind of pressure without the addition of ice.
video of it in action at 9 bar before it blew:


Original thread here:
http://www.spudfiles.com/forums/chappy- ... t2999.html

Later it was upgraded to 75 mm.Never had the sweet second piston valve though!

Hi all,

Maxus, what is a biatch?

I just had a serious backache yesterday; until that is over I am NOT going to shoulder it at 10 bar Yes, the pilot valve is very useful as a shoulder support. I will add a barrel support eventually - the static load on the tee is very very small. But of course the center of gravity is is off the barrel axis and the torque arm is quite short without a support.

I just taped the blowgun on for now, because I want to use a different trigger later. I am working on some push-button poppet valves, but they are not good enough yet.

And Hyldgaard, my pump is doing fine fine. I got the exhaust-side check valve built, and epoxied into the foot. I also got the pipe screwed into it. Just as I completed a floating O-ring piston and was about to fit it on the piston rod, I got hold of a bicycle pump. The piston from that fits amazingly well, so I am just going to use it instead. All I still have to do it to make a handle.

Regards
Soren

nice gun, i like the smooth and clean look

Hi BtB,

Hmm, interesting what u say about the PP pipe.

I could try to pressure test a length of it (bolting PVC on end caps, and supporting it in the longitudinal direction with a clamp). My high pressure pump is soon finished...

Regards
Soren