SpudFiles

DYI wrote:Well, I couldn't get it to work. With better equipment and more patience than I have, it is obviousl feasible. As long as the flow rate out of the tank is higher than the flow rate out of the pilot hole, the pressure should increase in the pressure bladder. If you are willing to spend $10 on another torch head though, using 2 tanks would be more efficient, and wouldn't need any tweaking to get it working properly.

nah, I don't want to carry two tanks. thanks for the input though!

night, fist day o' school tomorrow.

Well, heres my idea, it came to me after seeing a plunger system used in a cloud.
http://i30.photobucket.com/albums/c325/ ... sddsda.jpg
Propane is used, or I suppose if the piston was perfectly sealed you could use air, the piston is pressurized from behind and compresses the fuel.
The design is generic but I believe the principle is fine.

I think I would rather use a piston too. I wouldnt feel safe trusting a rubber tube. Military grade flame throwers may use this design but I doubt they get they're flame thrower bladders from Wal-Mart.

Oh and with a gravity feed setup the line back to the tank is devoid of oxygen as it's full of fuel. It can only ignite once it reaches the tip of the blowgun.

yeah someone on spudtech soaked a piece of pvc in gasoline and it wasn't any weaker.

thats helpful info but its kinda random i just looked up that today on the thought of flamethrowers
what you might want research is the gasoline resistance of that rubber bladder and the blowgun orings, I'd really trust a piston more cause its easy to find orings of various materials

yah know what would be cool a pump handle and for refilling a tube and a check valve, just dip the tube in the gas and pull 8)

It's a nice low-cost flamethrower design, but there are a few problems I see.

The use of a blowgun has already been discussed - just put a ball valve behind it for safety/main on-off valve, and use the blowgun as a trigger only.

Use a regulator or a separate propane tank for the pilot light, or you won't get much pressure in the main tank.

The entire tire tube design isn't necessary; if you flush the chamber of air (ensuring the atmosphere in the chamber is over 90% propane...) there's zero chance of combustion inside. The upper explosive limit of propane is 10.1%. As long as there's significantly more than that inside, no combustion can or will occur. The tire tube just complicates things.

I don't like the idea of tapping your fill valve into that small of a fitting, through just one layer of pipe. I also don't like the idea of using threaded PVC fittings on a flamethrower tank...

Check out this flamethrower design, it's pretty complete.... even has a fuel gauge. http://www.spudfiles.com/forums/flameth ... t8457.html

Good luck, it's a cool project.

Just be extremely careful about where you use it.

Peace,
Pete Zaria.

frankrede wrote:Well, heres my idea, it came to me after seeing a plunger system used in a cloud.
http://i30.photobucket.com/albums/c325/ ... sddsda.jpg
Propane is used, or I suppose if the piston was perfectly sealed you could use air, the piston is pressurized from behind and compresses the fuel.
The design is generic but I believe the principle is fine.

I'm useing a bike tire as a substitute for a piston because I think making a piston is too much trouble.

pete: the tire idea is not a matter of safety...I want to be able to tilt the tube upwards and not have the gas excape. infact I've already made a thrower similar to the design you liked.

Dornep wrote:I think I would rather use a piston too. I wouldnt feel safe trusting a rubber tube. Military grade flame throwers may use this design but I doubt they get they're flame thrower bladders from Wal-Mart.

Oh and with a gravity feed setup the line back to the tank is devoid of oxygen as it's full of fuel. It can only ignite once it reaches the tip of the blowgun.

the military doesn't use a piston or bladder..they use the gravity system. you didn't check the link.

rubber is fine with gas...something to do with long stretchy molecules or something.

also why cant the flame travel backwards when its gas vapors/air (ie: you almost out of fuel), don't reply to this as I don't care...

Since you don't care I won't go into any detail. Let us know how everything works out. Hopefully you'll be spraying flames and not undergoing a skin grafting operation.

Good luck