Posted: Thu May 17, 2007 7:32 pm
Well i got this from my well. I know it is not made of cast iron, but i will go to the junk yard and see what else i can scrape up. i would not mind something bigger either.
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Building propane-oxygen fueled launcher
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Posted: Thu May 17, 2007 7:36 pm
have you put a magnet to it to make sure
Posted: Thu May 17, 2007 7:45 pm
no. i will go and do that
Edit; went out to see, and the magnet sticks, but that is because it is steel
Edit; went out to see, and the magnet sticks, but that is because it is steel
Posted: Fri May 18, 2007 12:52 am
And steel is an alloy which is mostly iron.
Posted: Fri May 18, 2007 9:22 am
According to GasEq, stoichiometric propane in oxygen (at 1 ATM total pressure) gives a peak pressure of 250 PSIG at 3360C (6080F).
At 2 ATM total pressure the peak pressure is 530 PSIG.
Propane in air gives 120 PSIG.
Real world combustion guns don't usually get anywhere near the calculated peak pressure since the spud starts to move and the pressure drops. But, if the round jams then the chamber may get much nearer the theoretical peak pressure. 250 PSIG is close to, or more than, the pressure rating of large diameter PVC pipe. And, it is way over what a threaded cleanout plug will handle safely.
A metal gun, properly made, should be able to handle pressures in this range, even if the round jams in the barrel.
A rusty old hunk of iron, of unkown original use and specifications, is probably not worth the risk. It may look like minor rust on the outside but if it was used in a water system the inside may be in much worse shape than the outside.
At 2 ATM total pressure the peak pressure is 530 PSIG.
Propane in air gives 120 PSIG.
Real world combustion guns don't usually get anywhere near the calculated peak pressure since the spud starts to move and the pressure drops. But, if the round jams then the chamber may get much nearer the theoretical peak pressure. 250 PSIG is close to, or more than, the pressure rating of large diameter PVC pipe. And, it is way over what a threaded cleanout plug will handle safely.
A metal gun, properly made, should be able to handle pressures in this range, even if the round jams in the barrel.
A rusty old hunk of iron, of unkown original use and specifications, is probably not worth the risk. It may look like minor rust on the outside but if it was used in a water system the inside may be in much worse shape than the outside.
Posted: Fri May 18, 2007 9:40 am
like i said earlier, i am going to see if i can get a bigger tank that looks a little bit better. I will post pics of it when i get it.