Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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super spuder
- Corporal
- Posts: 558
- Joined: Fri Apr 06, 2007 9:05 pm
- Location: Ontario Canada
Sun Mar 22, 2009 9:27 am
I have been working on my first propane cannon on and off for a while now, i am stuck right now at making the meter. I went to TSC (they all know what im doing if i go in and start getting pipe and ball valves and stuff )
anyway, i grabbed all the parts i needed to make my injection system, and the one guy came up and told me not to use regular ball valves with propane, and i had to used these special ball valves that cost 3 times as much and that they are out of stock of the size i need for 1 month now! I have looked everywhere and no one has 3/4 inch gas ball valves, just regular ones. Is it really that bad to just use a regular ball valve? Also, do i need to use the really expensive gas hoses for camp stoves? I have just been looking though the other cannons on here and it doesnt look like many of them use either of the obove listed things
trying to decide on a new project, probably something small.
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Biopyro
- Corporal 2
- Posts: 654
- Joined: Fri Aug 04, 2006 5:32 am
- Location: UK
Sun Mar 22, 2009 9:30 am
I've never had a problem using gas ball valves with compressed air past 10 bar, and if I'm totally honest I don't know why specific gas ball valves exist. Buy the water one and cross your fingers
PVC pipe is not supposed to be used for air, but we do anyway.
As for the hose, I'm not sure, but personally I would be happy using any rated hose.
Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety. -Benjamin Franklin
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psycix
- Sergeant Major 4
- Posts: 3684
- Joined: Mon Jun 25, 2007 7:12 am
- Location: The Netherlands
Sun Mar 22, 2009 10:31 am
Naaah, it is just that when you install a gas line in your home, you gotta be 100% sure that it wont leak, so there are more expensive valves for that which are safer. If the valve would leak, it could slowly fill your house up with gas and cause an explosion.
But with us spudders, it doesnt matter if some propane is leaked does it?
On top of that, ball valves tend to seal very well and are usable up to very high pressures.
You can use the normal valves, you dont need to go from a 99% leakproof valve to 99,99% leakproof one.
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super spuder
- Corporal
- Posts: 558
- Joined: Fri Apr 06, 2007 9:05 pm
- Location: Ontario Canada
Sun Mar 22, 2009 11:28 am
alright thanks, going to pick some up after lunch!
trying to decide on a new project, probably something small.
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cdheller
- Specialist
- Posts: 126
- Joined: Wed Oct 05, 2005 5:30 pm
- Location: Austin Texas
Sun Mar 22, 2009 7:31 pm
A side issue would be gas systems inside a house are ounce's per sq in.
most of the valves for appliance cutoffs are listed at 15 psi max.
when we run gas lines regular ball valves are used everywhere else.
"A lot of what is taken for engineering fact is nothing more than somebody`s opinion when you dig into it far enough."
Henry "Smokey" Yunick, 1923-2001
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super spuder
- Corporal
- Posts: 558
- Joined: Fri Apr 06, 2007 9:05 pm
- Location: Ontario Canada
Sun Mar 22, 2009 7:34 pm
hmm never knew that, anyways, got there and they didnt have any pressure gauges that i wanted, so i talk to one of my friends and he said to check this other place, so hopefully i will have a working cannon in about a week or so. Thanks for the help
trying to decide on a new project, probably something small.
