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Posted: Sat Mar 17, 2007 7:59 am
by BC Pneumatics
125 psi @ 70*F is for pure propane though, lets not forget the gas vapors and other trace gases in there. (I wonder how much difference it would make?)
Posted: Sat Mar 17, 2007 10:29 am
by willarddaniels
I'm not an expert on propane, maybe you can educate me...
When you get a new propane bottle from the store or refill your existing bottle, what other trace gasses (liquified or gaseous) would you be getting along with the propane. And what are the evaporative points of these trace gasses?
I can imagine that there will be trace amounts of other gasses, but I can't see that the trace amounts would make that much of a difference. Maybe lower the liquification pressure to 120...
Posted: Sat Mar 17, 2007 10:39 am
by BC Pneumatics
I meant trace amounts inside the flamethrower tank.
Also, how would they lower the liquification pressure at all??
Posted: Sat Mar 17, 2007 10:51 am
by LGM
I have used a coleman's propane tank and a stove hookup as a flamethrower with 6-8' of flame, they work fine.
Posted: Sat Mar 17, 2007 10:58 am
by BC Pneumatics
LGM, read the entire topic. We are not talking about LP flamethrowers, of which I have a few. We are discussing using propane or other flammable gases as a propellant in liquid-fueled 'throwers.
Posted: Sat Mar 17, 2007 11:06 am
by LGM
I have. Earlier in the thread there was a discussion about LP as a fuel, and it was mentioned that it was not very good.
Edit: what about alcohol as a liquid fuel, a several yard long blue flame would be neat.
Posted: Sat Mar 17, 2007 11:08 am
by willarddaniels
I hear ya BC (not BS - sorry) We are saying the same thing / working on the same concept.
That aside:
I think that even if the propane was liquified, it shouldn't affect the function of the flame thrower. A highly pressurized liquid propane would be effective in propelling the liquid fuel. As the flamethrower is used, it reduces the pressure inside the cylinders and thus the propane returns to a gaseous state. When using the propane/butane/whatever as a pilot or propellant, the pressure is reduced when the fuel dissipates as well as when the propellant goes through the regulators. Also, the vapor pressure of butane is 30 psi.
Again... I'm no expert, just a thinker.
Posted: Sat Mar 17, 2007 11:14 am
by BC Pneumatics
I have mine set up very simply with a ball valve between the propane tank and fuel tank. The LP simply boils and pressurizes the fuel.
LGM, when referencing something that happened more than a few posts ago, it is a good idea to quote what you are responding to to avoid confusion

Posted: Sat Mar 17, 2007 10:31 pm
by DeathBlade
I've made electric flamethrowers, before, not much range but, no compressed air.
http://www.youtube.com/profile?user=DeathBlade556
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Posted: Sun Mar 18, 2007 9:10 am
by BC Pneumatics
Pretty neat deathblade! I assume by electric, you mean the fuel is being expelled via a pump?
Posted: Sun Mar 18, 2007 11:59 am
by imjustpk
LGM
"Edit: what about alcohol as a liquid fuel, a several yard long blue flame would be neat."
I've actually seen this, instead of using metal tanks and gasoline as a fuel some people use pvc for their tank and use denatured alcohol for fuel.
This may be a dumb question, but is there a list of materials that gasoline will corrode? Because I was thinking of a flamethrower and possibly using a 2 liter soda bottle, but I don't know if it would be eaten away by gasoline or not.
Posted: Sun Mar 18, 2007 1:41 pm
by BC Pneumatics
Soda bottles are made of HDPE... Off to google you go!
Posted: Sun Mar 18, 2007 5:09 pm
by zeigs spud
very nice! i'll add those 2 to the first post.
Posted: Mon Mar 19, 2007 9:50 am
by DeathBlade
By electric I did mean pump powered, the pump is just a 5$ replacement pump for a windshield wiper. And the tank was from a gallon of acetone. with a 12v 2ah battery.
Posted: Mon Mar 19, 2007 1:44 pm
by BC Pneumatics
Pretty impressive for a windshield wiper pump.