This article was taken from the November 2011 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
Military flamethrowers shoot a flaming liquid such as napalm, and commercial and agricultural versions are propane-based. Neither type is completely safe to use, but propane devices are less dangerous. The non-liquid- fuel, propane flamethrower described here is technically a propane accumulator cannon.
But that's a minor point -- anyone who sees it work knows it has the heart and soul of a flame thrower. Built and operated correctly, it will shoot a Sun-bright, roiling fireball five to ten metres straight up in the air. Built and used incorrectly, very bad things could happen. Use common sense. No guarantee of safety is made or implied. Attempt this How To at your own risk. williamgurstelle.com
SAFETY INSTRUCTIONS - Do not operate the flamethrower near combustible materials -- including people.
Stay well away from the nozzle when operating.
Wear protective clothing and eyewear.
Have a fire extinguisher close by.
Use caution at all times. This is a flamethrower.
COLLECT THE COMPONENTS
The propane flamethrower has several key parts. The only hard-to-find one is the steam valve, but these can be found on steam-engine hobby sites. - Propane cylinder
Regulator and hose
A base frame made from steel pipe
A flare fitting, which connects the propane hose to the steel pipe
Accumulator tank
Propane pilot-flame torch
Pull-operated steam valve
Nozzle assembly
Pipes and pipe fittings
1. CONNECT THE PARTS
Connect the tank to the steam valve, nozzle and flare fitting.
You'll need to link the 5cm-diameter accumulator pipe to the steam valve and nozzle on the top, and the flare fitting on the bottom.
2. BUILD A BASE
Build a wide, sturdy base to hold the flame thrower. There are many ways to do this. You can use a large, stabilised pipe or weld up a holder, depending on how handy you are with a blowtorch.
3. ATTACH THE NOZZLE
Attach the propane pilot-flame bottle to the flamethrower using hose clamps. Position the pilot nozzle so that it is directly over the flamethrower nozzle -- it won't ignite otherwise.
4. HOOK UP THE GAS
Connect the high-pressure regulator to the propane tank. Turn the gas valve on the main gas cylinder on and test the connections for leaks with soapy water (leaks will create froth).
5. DON YOUR SAFETY GEAR
Clear the area beneath the flamethrower nozzle for a minimum of three metres in all directions. Propane is heavier than air, so don't stand underneath the nozzle when you operate the device.
6. LET RIP
Open the valve on the small propane bottle and ignite the pilot torch. Then open the valve on the main gas cylinder, and step 3m away from it. Slowly pull the rope attached to the steam valve to release a little propane. Once a small flame is present in the nozzle, pull the valve completely open and let rip. A small flame from residual propane in the nozzle will be present for several seconds. This can be used to ignite subsequent fireballs. Release the valve to stop.
This article was originally published by WIRED UK
