Propane, Pure Oxygen, and PVC

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.
sandman
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Fri Jun 22, 2007 11:06 am

SpudBlaster15 wrote:*Cues GasEQ*

Oxygen/Propane, 1atm - 18.181atm (267psi)

Atmospheric air/Propane, 4atm - 38.015atm (559psi)

Oxygen/Propane, 4atm - 76.28atm (1,121psi)

Keep in mind these are adiabatic values, and the actual combustion pressures (non adiabatic) will be significantly lower.
Im just wondering if anyone has a problem with these numbers, cause when i get my combustion gun done i might upgrade it to Oxygen, but i wont to make sure ill be safe
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spudmonkey
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Fri Jun 22, 2007 10:27 pm

what would a 4X hybrid do if it was filled with O2 and Mapp gas? cause woulndt that have a fuel load of aprox. the same as a 20x hybrid?
Never Argue With An Idiot, They Bring You Down To Their Level, Then Beat You With Experience
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boilingleadbath
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Sat Jun 23, 2007 6:59 am

In smiles notation, MAPP gas is a mixture of C#CC and C=C=C.
Acetylene is C#C.

See the similarities?

The extra carbon-carbon bonds make the chemicals more reactive, and so they share many of acetylene's properties - notably it's high burn rate.

Admittedly, the they aren't as reactive as acetylene, but it still seems... dumb to use them in a pure oxygen environment, especially considering how easily propane-O<sub>2</sub> transitions.
Scotty
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Mon Jun 25, 2007 1:50 am

4 % oxygen and 96 % oxygen will not go bang.
The air you breathe has 21% oxygen and the rest is mostly nitrogen as said before.
Do some basic math and you will be able to work out how much propane you need ( around 4 times the amount you said.)

Peace
Scotty
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