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Killjoy's Flamethrower

Posted: Sat Mar 31, 2007 12:34 am
by Killjoy
Nothin new here, simpleish flamethrower that I built for about $70 bucks in a day. I use it as a flamethrower for burning weeds and entertaining
my slightly intoxicated friends, as well as a supersoaker for cleaning my car and house windows.
The two tanks are 4" inch diameter pvc, which are 2 feet long. This gives me a theoretical fuel capacity of 2.6 gallons, though i tend to only use one gallon of fuel at a time, generaly Denatured alcohol cause I can get a real good price on it and it works great.
Its meant to have a regulated co2 setup, but i have been lacking in funds since my new hybrid and haven't bought the stuff, so i just compress the fuel with air and use a schrader valve to fill the tanks with air (ain't real safe but it works). Sorry i don't have any pics of it in action, but the new neighbors have been "frowning" on my activities recently, and it doesn't help that i have a cop living two doors down from my house.
The tanks, connected together with 1/2 inch copper pipe.
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The nozzle, theres also an adjustable flame valve mounted on it. (i also added a checkvalve for safety, though im not sure it will really help.)
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The pilot flame
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Me with it strapped to my back, i used a shoulder strap from a golf bag. This thing weighs about 35 pounds when filled to capacity.
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Posted: Sat Mar 31, 2007 12:40 am
by c19o
Nice, I've always wanted to build one but my parents get mad if I use things that make huge flames. Even my mini combustion my dad worries about.

Posted: Sat Mar 31, 2007 1:17 am
by singularity
thats pretty sweet, but did you say you got a cop living two doors down... you got balls man. i took some empty propane tanks from my town dump and the god damn cops confiscated them, but maybe the cops in your town aren't a$$ holes (which would be a first)

Posted: Sat Mar 31, 2007 1:39 am
by ArticWolf
That thing looks sweet. Have you used it yet? If so, How big is the flame? What pressure do you use with it? I might have to try something like that some time in the near future. LOL

Posted: Sat Mar 31, 2007 2:29 am
by TwitchTheAussie
man that is freaking awesome. Gonna paint it?

Posted: Sat Mar 31, 2007 3:59 am
by Recruit
Umm isn't it safer to use propane or butane to pressurize it since they wont combust if there is to much in there area ,ie the tank.

Looks cool.

Posted: Sat Mar 31, 2007 5:23 am
by jrrdw
If your nabiors are worried about the little (lol little) flame thrower, wait untill you start blasting away with the hybird. I have to amit i'm not to crazy about flame throwers, danger level, but they do look really cool in action.
Does the fuel puddle up on the ground when you keep it in one place(when firing)? Or does it evaporate to quickly?

Posted: Sat Mar 31, 2007 8:35 am
by pyromaniac
If you look at alot of posts its cool to see that some cops are interested in spud guns.
Nice flame thrower. i want to make one but my dad wouldn't allow it.
How long will it fire when its full?

Posted: Sat Mar 31, 2007 10:53 am
by Kenny_McCormic
thats cool but those reducers and cleanouts arent pressure rated. pressurizing it with air isnt a good idea either.

Posted: Sat Mar 31, 2007 12:34 pm
by benstern
Yeah, i was about to say you got DWV fittings on it. It would suck if they blew apart when you were using it as a flamethrower.

Posted: Sat Mar 31, 2007 12:50 pm
by noname
Yeah, a bunch of fuel raining down on you would kind of suck, especially if you were shooting or had the pilot light on.

Posted: Sat Mar 31, 2007 2:09 pm
by zeigs spud
very nice, the nozzel that the fuel exits to hit the pilot flame is pvc plastic, does it vet very hot back around it or is it prettymuch okay? if it does i sugest a metal one.

Posted: Sat Mar 31, 2007 3:01 pm
by Killjoy
Yeah i know the fittings are dwv but i keep the pressure at about 90 psi which works great, and doesn't make me worry about the fittings giving out. I also can get about a 30-40ft long flame with it.
Zeigs,
The actually nozzle part is a brass 1/4 inch pipe barb, the check valve is somesort of heavy duty plastic, and the rest is steel pipe (with a few copper connectors) with a 1/2 inch ball valve.
jrrdw,
Well the hybrid is about 55 feet long so i can't exactly test it at my house with out it being notice, but i do have a test sight with no houses around it for 5 miles or so.
pyromaniac,
my parents said the same thing, so i claimed it was a "super soaker" while i built it, then i broke the news to them slowely about its actual use (which they took pretty well, since i usually use it to burn weeds). And im not sure how long it will last when its full, i think i can get about a minute of continuos firing with water, so i would guess the same with fuel (but then it might over heat so i won't try it). I usually fire it (right word?) no longer then about 10 secs at a time. And it will puddle on the ground if i let it (but it doesn't burn for very long).

Posted: Sat Mar 31, 2007 3:03 pm
by benstern
I would be NEVER use dwv fittings at an operational pressure of 90 psi.

Posted: Sat Mar 31, 2007 3:11 pm
by Killjoy
hmm ok then, i do and haven't had any problems (and i have pressure tested them to 135 psi and banged around a little bit while they were pressurized bla bla bla.) Look i know its not a good idea, but this is all the basterds at home depot had and didn't know about mcmaster yet when i built this, and im not chucking it cause of the dwv fittings. now then, if anyone else builds one, they should use pressure rated fittings, that said, could you guys refrain from reminding me that there are dwv fittings on this and the dangers that are present, I know the dangers of using them, and if i choose to still use them, then thats my problem.