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Posted: Tue Apr 08, 2008 12:23 am
by jon_89
Do you think a propane fill will have enough flow for a piston gun?
Posted: Tue Apr 08, 2008 12:30 am
by Carlman
depends how tight you piston is, but most probobly
Posted: Tue Apr 08, 2008 12:35 am
by Lentamentalisk
jon_89 wrote:Do you think a propane fill will have enough flow for a piston gun?
What do you mean?
filling a tank with propane is like hooking your gun up to a compressor. I think you may mean for a BBMG, and that all depends on your valves, though I highly doubt it.
Once again, I think using propane as a compressed air source is a terrible idea and will probably either end up with you on fire, or it will smell so bad that you cant aim your next shot, and then blow your self up. Suck it up and get a CO<sub>2</sub> tank or buy an air compressor, or at least do something cool like light the propane at the muzzle so that you get a cool muzzle flash and don't blow your self up with all the gas building up.
Posted: Tue Apr 08, 2008 12:49 am
by Carlman
have you seen chaos's vid of the s400 running on bbq propane?
worked a treat
Posted: Tue Apr 08, 2008 12:56 am
by Lentamentalisk
So he hasn't exploded yet? Well wear you safety glasses, and don't say I didn't warn you if you do explode. Make sure to post this somewhere on your gun though.

Posted: Tue Apr 08, 2008 2:35 am
by biggsauce
Hey yall dont mean to intrude on this thred, but I am doing some of the same calculations for a similar problem. PV=nRT seems pretty straight forward, I had never thought of applying this to cannons though... goes to show you CAN use the stuff they taught ya in school! ( who knew )
I am looking to charge a 2"x3' chamber (1.85L) to 50psi (3.40atm) with a 21oz CO2 bottle. So, (1.85)*(3.40)*(chamber fills)=(.08206)*(300k)*(#moles). Since CO2 is 44 g/mol, and 21oz is 595.34g, then my moles of CO2 should be 13.5. So I should get 52.84 fills???
Either its just really late and I can't do simple gas law anymore, this tank is going to really go the distance. Did I mess up?
Posted: Tue Apr 08, 2008 10:00 am
by Lentamentalisk
good, though technically its ont 3.4atm, its 3.4bar, as atm starts from a vaccuum, and psi starts from 1atm, but you are just adding 3.4atm so it still works.
not sure about your math, dont have time to figure it out now.
Posted: Tue Apr 08, 2008 12:57 pm
by biggsauce
Ah, ok. Didn't think about not starting from a vaccuum, thanks. Can anyone else find errors in my math?