Propane Pneumatic Problem

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Sonicboom101
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Wed Feb 18, 2009 9:31 pm

I having some troubles using propane on my newly made pneumatic gun, I basically have a blue propane cylinder, that goes to a ball valve, that goes to an air chuck. I have a pressure gauge attached to the chamber to monitor pressure. When I let propane pressure into the chamber via shrader valve with the air chuck. The pressure gauge barely moves and the sprinkler valve diaphragm does not seal. I the tank gets extremely cold as well. I have cleaned out my valve and added grease to see if was a valve sealing issue. But I am still not getting enough pressure. Should I step up do a big propane canister? Would that give me enough pressure and with out the chill of the cylinder and fix the sealing issue as well?
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hi
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Wed Feb 18, 2009 9:36 pm

i think your problem is that its filling to slowly. diaphragm valves need about 5-10 psi to seal. if its fills too slowly then it leaks out. i think the best solution is to have a separate chamber, maybe 6'' of 1'' pvc and inject it in all at once. that should fix it.

Are you using a orbit sprinkler valve? if you do, they have a piece of plastic on the diaphragm that needs to be removed. it pugs up the equalization hole. why they put it there i dont know, but after you remove it then that should fix the problem.
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ckman
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Wed Feb 18, 2009 9:38 pm

Why waste the propane if you are filling it with a schrader you might as well use a bike pump.
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Sonicboom101
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Wed Feb 18, 2009 9:43 pm

Yes I am using a Orbit Sprinkler Valve, Its the exact model shown in How to NO DRILL SPRINKLER MOD Tutorial. When I look at the diaphragm there is a white looking thing that looks like a plastic gear. Is this that White Thing the peace of plastic you were referring to? Ill look into that other suggestion as well.
Last edited by Sonicboom101 on Wed Feb 18, 2009 9:47 pm, edited 1 time in total.
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Lentamentalisk
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Wed Feb 18, 2009 9:45 pm

Why waste propane?
Because bike pumps don't come as a precompressed liquid in portable little bottles. You use propane for the same reason that someone would use a regulated CO2 setup.
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hi
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Wed Feb 18, 2009 9:46 pm

Sonicboom101 wrote:Yes I am using a Orbit Sprinkler Valve, Its the exact model shown in How to NO DRILL SPRINKLER MOD Tutorial. When I look at the diaphragm there is a white looking thing that looks like a plastic gear. Is this that "White Thing" you were referring to? Ill look into that other suggestion as well.
yup.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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Sonicboom101
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Wed Feb 18, 2009 9:49 pm

Ok, Thanks Ill let you know how it works ill keep you posted. :D
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ckman
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Wed Feb 18, 2009 10:00 pm

Lentamentalisk wrote:Why waste propane?
Because bike pumps don't come as a precompressed liquid in portable little bottles. You use propane for the same reason that someone would use a regulated CO2 setup.
Very true but....
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Lentamentalisk
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Wed Feb 18, 2009 10:05 pm

But what? I am confused.
You do realize that "green gas" which they use in airsoft pistols is propane with a more expensive label, right? There is nothing odd about using propane. In fact, it is considerably cheaper than CO2, and doesn't have such dangerously high pressures, so can be regulated with a cheap $10 regulator, as opposed to the $50-60 CO2 regs.
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sputnick
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Wed Feb 18, 2009 10:06 pm

I'm with ckboy here, not so much because its a waste of propane, because I do agree with the c02 point, but because the odorant they add to propane would make that one of the least pleasant guns to fire, smell like crap unless you set the exiting gasses alight during every shot, which is a pretty stupd concept,
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Lentamentalisk
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Wed Feb 18, 2009 10:09 pm

Yet again, siting airsoft guns, it is done all the time (granted probably not at such high volumes) with propane tank adapters, to save a fortune on green gas. It would stink some, but with the slightest of breezes it wouldn't last long.
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hi
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Wed Feb 18, 2009 11:27 pm

i don't know why you are arguing. If he wants to spend $3 on a propane canister, why do you care? you guys are off topic. he is asking for help with a sprinkler valve, not weather or not to use propane.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
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starman
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Wed Feb 18, 2009 11:30 pm

I live for propane stink...as well as gasoline, paint thinner, etc. smells. Obviously I'm not stupid enough to over inhale such things but I don't skip an opportunity to catch the breeze, so to speak, if it's close by.
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Sonicboom101
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Thu Feb 19, 2009 11:08 am

hi wrote:i think your problem is that its filling to slowly. diaphragm valves need about 5-10 psi to seal. if its fills too slowly then it leaks out. i think the best solution is to have a separate chamber, maybe 6'' of 1'' pvc and inject it in all at once. that should fix it.
Could you explain a little bit more in detail about that separate chamber? I think I get the general Idea though but how would that 6''x1'' pvc pipe attach to the shrader valve? Would it have a ball valve to release the propane all at once without chilling the tank, and a air chuck? Sorry about the confusion, but thanks for all the help.
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Thu Feb 19, 2009 11:32 am

I suspect HI is correct, you are filling to slowly.

How do you have the Bernzomatic torch cylinder plumbed? (I assume that is what the "blue cylinder" is.) If you removed the air mixer from a torch head and attached a hose to it then you are delivering fuel through the tiny little hole in the torch head. That'll deliver gas very slowly, probably to slowly to set the piston.

A bit more detail, either a drawing or a photo, would be helpful.
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