Converting an array of air tanks for spud gun use

[Caramanos2000]

hello, I am currently in the design process of my second gun, which I am hoping to build with either a 20lb propane tank or a 15lb extinguisher, any 1 got any tips, suggestions? etc?

[spudshot]

empty them before you do anything to them

why do you want to use a prop. tank or fire extinguisher tank? more pressure? safety? coolness factor?

[sergeantspud2]

extinguishers are co2 right so you can hook a co2 tank directly to it without a regulator. you could get really high psi

[spudshot]

uh NO if i remember right they're filled to about 200 psi, NOT 800

[sergeantspud2]

oh sorry i thought all co2 was the same psi

[spudshot]

sorry if i came off harsh, that just really set off a safety alarm, 800psi of super cold unregulated co2 in a thin aluminum tank...

[sergeantspud2]

i was thinking about doing that so thankyou for telling me not to

back on topic: i would use the extinguisher just because it looks cooler

[iamthewalrus]

spudshot could u put unreg co2 in a like 5 or 10gl EMPTY propane tank?? not that im going to now, but in the future who knows...

[spudshot]

propane liquefies at 90psi, so i dont think the pressure in a 10lb would be much more than that of a bernzo tank, so i wouldnt do it, i know the safety valves on bernzo's have a pop pressure of something like 200 psi, dont quote me on that, so i dont think it's be particularly safe to put unregged co2 in it.

[Caramanos2000]

First of all extinguisherswork at 200PSi and propane tanks are rated to 400psi. So i wana do it fore safety, more psi, and easier to paint, A lot of power. Estimates with the propane tank at 150psi are around 2000fps.

[spudshot]

impossible, you'll never get over the speed of sound with air unless its heated to a very high temp., if you want to break the sound barrier, go helium

[iamthewalrus]

umm spudshot, http://www.spudtech.com/content.asp?id=10, look at the last pic, thats a pnumatic and he broke 1200fps, did he use helium??

[spudshot]

i'm not sure if joel did or not, he didnt chrony it, he just said he heard a loud noise, which he believed to be the sonic boom from breaking the barrier

[iamthewalrus]

ic, so does that mean only hybrids can basicaly break 1200fps, or can normal combustions and pnumatics (with helium) too

[spudshot]

no way an average combustion could break the sound barrier