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Why did I fail?

Posted: Sat Sep 12, 2009 6:09 pm
by spudnutbutthut
Wel, some of you may remember my propane powered pneumatic canon thread.

Well, I attempted it.


propane bottle connected to a camp stove burner adjuster knob, that goes through a hose to a hose barb that is mounted in the chamber. The chamber is 2in and is supposed to pressurize. Then I have a modfied sprinkler valve that goes to a 2 inch barrel. When I put in the propane tank, turn on the burner etc. the chamber doesn pressurize or leak.... I have a pressure gauge. When I press the sprinkler valve trigger (blowgun) the propane comes out of the bottom of the blowgun and the diaphram doesnt open. :( What am i doing wrong, why is there NO pressure but gas still flows.

Posted: Sat Sep 12, 2009 6:15 pm
by jor2daje
I'm pretty sure camp stoves have built in regulators to keep the pressure low, how did you connect the camp propane adapter to you gun, you should modify a cheap pencil torch.

Posted: Sat Sep 12, 2009 6:30 pm
by D_Hall
jor2daje wrote:I'm pretty sure camp stoves have built in regulators to keep the pressure low, how did you connect the camp propane adapter to you gun, you should modify a cheap pencil torch.
What he said. Camp stoves generally operate at only a few psi.

Posted: Sat Sep 12, 2009 6:57 pm
by spudnutbutthut
Ok i switched to a pencil torch, it pressurizes but when i pull the trigger the propane comes out of the bottow of the blowgun and the membrane dosent open... :( there is also some leaking from the sprinkler valve...WTF?!

Posted: Sat Sep 12, 2009 7:04 pm
by jrrdw
Is the arrow on the sprinkler valve pointed towards the barrel or chamber?

Posted: Sat Sep 12, 2009 7:05 pm
by spudnutbutthut
the barrel it says "FLOW -> " toward the barrel.

Posted: Sat Sep 12, 2009 7:06 pm
by jrrdw
Are you getting to 30psi and above quickly?

Posted: Sat Sep 12, 2009 7:07 pm
by spudnutbutthut
around 25 + yes, not QUICKLY but pretty ok speed why? it was at 20 i think...

Posted: Sat Sep 12, 2009 7:12 pm
by jrrdw
Sometimes sprinkler valves diaphrams won't seal until you reach around 30psi, the quicker the better. Take it apart and see if there is any debree causing it to not seal correctly.

Posted: Sat Sep 12, 2009 7:13 pm
by spudnutbutthut
should the bottom of the sprinkler valve be epoxied shut?

Posted: Sat Sep 12, 2009 7:21 pm
by jrrdw
The only reason to epoxy would be if the solonoid was removed and the hole would need filled.

Posted: Sat Sep 12, 2009 7:28 pm
by spudnutbutthut
okay, it pressurizes quickly to 60 psi, then when i press the sprinkler valve it lets the gas out the bottom of it.... :( WHY>!

Posted: Sat Sep 12, 2009 7:32 pm
by jor2daje
What sort of sprinkler valve are you using?

Posted: Sat Sep 12, 2009 7:34 pm
by jrrdw
What kind of blow gun are you venting the sprinkler valve with? Try loosening the blow gun enough so you can take it off as fast as you can, pressurize the chamber the yank the blow gun off and see if it releases the stored air out the barrel.

Posted: Sat Sep 12, 2009 7:53 pm
by MrCrowley
jrrdw wrote:What kind of blow gun are you venting the sprinkler valve with? Try loosening the blow gun enough so you can take it off as fast as you can, pressurize the chamber the yank the blow gun off and see if it releases the stored air out the barrel.
Wouldn't it leak out the blowgun where it's threaded in to the sprinkler valve or damage the threads if you yank it out?

Is your blowgun up the right way? Do you have a hose between the valve and blowgun or is the blowgun directly connected to the valve? How big is your chamber?