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Posted: Sun Apr 22, 2007 2:16 am
by mega_swordman
It should work because yes, for propane or any other fuel to ignite, there is a air to fuel ratio. Too much or too little fuel will not ignite.
Posted: Sun Apr 22, 2007 3:10 am
by to_live
i have a propane bb gun ready to be used sitting in my room, i just have to buy a new peice of brass for the barrel, it worked pretty well, at 10 feet it left dints in my fence with plastic bb's. ill take some photo's after!
Posted: Sun Apr 22, 2007 3:11 am
by hi
it would be way cheaper to use propane. its like $3 a bottle and will give you a lot of shots. co2 needs a regulator, adapter, and the tank it self. all that is around $75-100. propane you need some hose, some hose clamps, torch head, a ball valve, and a bottle of propane. that would cost about $35.
so it $75-100 for co2 vs. $35 for propane, which would you rather have?
Posted: Sun Apr 22, 2007 1:43 pm
by benstern
Mine gets 4-5 shots from one of those small cylinders. However my cannon is fairly large.
Posted: Sun Apr 22, 2007 2:23 pm
by pyro6314
why not try to make it a hybrid? Have the propane flow constant into a chamber with a burst disk that doesn't really burst but just releases the pressure at a set psi. Ive seen these in the oil field but you probably wont find a scaled down one.
Posted: Sun Apr 22, 2007 2:28 pm
by mega_swordman
And now I know,

it was sort of a no-brainier question. We always look dumber in retrospect.
Posted: Sun Apr 22, 2007 2:35 pm
by pyro6314
Technically, I would think you could make a hybrid out of a piston valve. Put a compressor relief valve behind the piston that is above the "charge" pressure. (say 160 if it were to be copper) When the propane ignites, the pressure difference should push back the piston decreasing the pilot volume until the blow off valve releases. While this is happening all the pressure is buggering off out the barrel.
I guess that technically counts as a set pressure relief valve or bust disk.
Edit: Sry, just realized this has been covered in the hybrid section.
Posted: Sun Apr 22, 2007 6:30 pm
by frankrede
hi wrote:DR made one one time. he used a bottle of propane and a torch head. it was i think a tennis ball launcher. it looks really cool. It was on spud tech. ill see if i can get you a link. I think he also use a 1'' sprinkler valve.
That cannon is fun to shoot! but beware of any open flames around it while using it.
Posted: Thu May 17, 2007 1:14 pm
by FeLeX
I am VERY sorry to kick up a "dead" topic but I thought of making a pneumatic propane rifle about a week ago and started looking arround to see if it was done before and aparently it has. I still want to do it but I still have a question. How many shots would you get out of a propane tank? For example if you have that tennis ball gun that DR made?
One more time, sorry to kick up "dead" toppic but I just didnt feel like making my own and then having poeple call me stupid for not using serach button.
Posted: Fri May 18, 2007 6:33 am
by wannabie
Has any one thought of LPG? it would work fine wouldnt it?
Posted: Fri May 18, 2007 6:46 am
by ShowNoMercy
LPG? What is that?
Posted: Fri May 18, 2007 7:06 am
by chaos
LPG has bigger molecules but it would work the same as propane, i tried it and its not great but thats just me, un-metered i had about 100psi and i got more that 50 shots off with my s400
Posted: Fri May 18, 2007 2:09 pm
by meatballs
LPG means liquified petroleum gas. aka propane. LPG would work fine, but LPG may also be a blend of propane and butane, which would lower the pressure. it should still work, just be sure the LPG is mostly propane. propane would have the pressure you need. LPG has the same risks and drawbacks as propane (obviously, since it is propane) but other than that would work well.
Posted: Fri May 18, 2007 5:49 pm
by chaos
Yes i have tied it and it does work there are a few regrets after doing it though:
link:
http://www.spudfiles.com/forums/pnuemat ... t7934.html