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Finally a big (relatively) pneumatic

Posted: Wed Jul 15, 2009 10:02 pm
by jor2daje
Well I got tired of using the macro on my camera :wink: so I decided to do something a little bigger that brass penguns.

Its a barrel sealing piston valve built in a 2 inch tee with 1.5 inch porting. My piston is a 1.25 inch coupling with two rubber tiles as my sealing face. Its piloted by my old .75 inch sprinkler valve. It has a 2 inch chamber and a 2.5 inch barrel, perfect for firing tennis balls. This makes the c:b wrong so I might slightly cut down the barrel.

I know there are quite a few unnecessary fittings but I wanted to make a removable piston valve so I can use it on different cannons. I build the whole cannon for $25 reusing several parts from old guns like the sprinkler valve.

So far I have only fired tennis balls at around 60 psi, that will go up soon. This gun was built more for flinging tennis balls a long way and less for damage, however I may try it out on some plywood just for fun.

Im going to paint it tomorrow, planning on doing some white and blue with my airbrush.

Posted: Thu Jul 16, 2009 12:41 am
by glass_05
nice looking cannon. very clean looking piston and good work on the bumper. very clever to use parts from a shopping cart.

Posted: Thu Jul 16, 2009 1:34 am
by Technician1002
Barrel too big is only Dependant on pressure. Higher pressure stores more air than low pressure. As a test I tried going extreme. A 7 foot TB barrel on a little 54 cu in tank. At below 50 PSI it fails to launch. At 110 PSI it launches very well. The expansion is about perfect for almost silent launches with good hang time. Listen to it. The valve is louder than the muzzle blast.

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