Instructables

how does a blow torch work

i was thinking of making a mini blow torch. but i have no idea how it works or hot to make on. my bro has this mini torch that give out a blue flame. it just uses a simple refeulable cartridge. it uses butane. i have a barbecue lighter i dissected and i want to make one. but does anyone know how it works or how to make one?

DzakirH3 months ago

Maybe, you should try dissecting your Bro's blue flame and have a look inside. That would be a normal lighter catridge which is refillable connected to a sillicon tube to a compressor with air holes and together with the wire from the Piezo Electric sparker to ignite it. Try examine the compressor, you would see air hole(s) which works pretty much similar to a bunsen burner. I'm not really sure how it works but I do know that it compresses the gas with the air in the surroundings going through thr air hole

gck246 years ago
hey I need to know how a blow torch works like a diagram. when I tried to blow up the one pat sowers sent it got really blurry. I've been looking for several days for a diagram like that but can't find any could you help me out?
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DELETED_DELETED_kruser495 (author) 7 years ago
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If you want it to be hot you need to add oxygen. Listen I dont know 100 percent if this will work but you can try it at your own risk! First go to the home depot and get some strong steel pluming parts (get a pipe that is 4 feet long of a small diameter about 1/8 to 1/4 inch. (This pipe should be the thickest and strongest material you can get your hands on.) Then get two valves that will allow you to make a slight adjustment. (They should be able to fit the 4-foot pipe I told you about by welding a "Y" shape (more of a tuning fork shape) out of part of the pipe.) Each end of the "Y" (the "V" shape part than bends to go horizontal) should have a valve welded to it. On the other end of the valves you will have your gas lines that will run to the gas tank and the other to the oxygen tank. (Oh and all the welds should be done by a pro so that they can take high pressure) Next comes the part that should keep your hand from burning. Get a pipe that will fit the entire pipe in it but dont cover the part where the two pipes come together as one. (This pipe should be big enough to have a one-inch space on each side of the gas line and the oxygen line. This will be attached bye welding small parts of metal from the outside of the shroud to the gas pipe on both end and the same for the oxygen line. If you do try this you open the gas line a very small amount so you just hear a small hiss sound. When you hear the sound immediately light it with a striker. When it is burning add more gas to get a slightly bigger flame and then open the oxygen valve very slowly till you see a blue flame. This should be about 6000 degrees F. when you use this where the thickest leather gloves you can bye and where safety goggles. I warn you now this has never been tested and it could blow sky high if it is done wrong. Take a look at the diagram I gave you as a guide to help you build it. Please I beg you If you do try this get help from the pros so that they can help you!
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Crap! I spent all that time typing that and thats not what youre looking for! OMG! Ok im calming down now. I will get back to you on that in a few minutes I got to do some quick research for ya.
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The chemistry....Combustion (fire!) requires both fuel and oxygen (air). When butane gas burns completely, with sufficient oxygen, it burns with a blue flame at 1300 degrees Celsius. With ordinary lighters the combustion of butane is incomplete, resulting in a yellow 'flame' due to the glowing particles of carbon oxidizing slowly to C02. The physics....The reason for the different combustion properties of pocket torches and ordinary lighters has to do with the 'head' (actually called a 'fire nozzle') that you described. This nozzle is basically a metal plate containing very small holes. Air is sucked in from another hole in the side of the nozzle and is then forced through the small nozzle holes. The very small size of the holes causes a pressure build-up (and therefore very high gas flow velocity) which has two important effects. First of all, enough air (oxygen) is drawn in to completely combust the butane. Secondly, the resulting flame shoots straight out and is "strong" enough to withstand windy conditions without blowing out. A good analogy is the effect of putting your finger on the end of a water hose. The smaller the opening, the greater the force of water exiting the hose. Two other aspects of the pocket torch which you may find interesting are an internal catalyst coil and piezoelectric ignition. Unfortunately I wasn't able to find out too much about the catalyst. The piezoelectric ignition, standard to most lighters, involves a quartz crystal which, upon being hit sharply, produces a high voltage electric discharge (a spark) which ignites the butane/oxygen mixture. i got this from a site.
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a torch for burning pockets ? Oh you mean like this pencil torch ?
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The jet, etc. being so small, would be even harder to work with then a normal sized one.
i have no idea
The chemistry....Combustion (fire!) requires both fuel and oxygen (air). When butane gas burns completely, with sufficient oxygen, it burns with a blue flame at 1300 degrees Celsius. With ordinary lighters the combustion of butane is incomplete, resulting in a yellow 'flame' due to the glowing particles of carbon oxidizing slowly to C02. The physics....The reason for the different combustion properties of pocket torches and ordinary lighters has to do with the 'head' (actually called a 'fire nozzle') that you described. This nozzle is basically a metal plate containing very small holes. Air is sucked in from another hole in the side of the nozzle and is then forced through the small nozzle holes. The very small size of the holes causes a pressure build-up (and therefore very high gas flow velocity) which has two important effects. First of all, enough air (oxygen) is drawn in to completely combust the butane. Secondly, the resulting flame shoots straight out and is "strong" enough to withstand windy conditions without blowing out. A good analogy is the effect of putting your finger on the end of a water hose. The smaller the opening, the greater the force of water exiting the hose. Two other aspects of the pocket torch which you may find interesting are an internal catalyst coil and piezoelectric ignition. Unfortunately I wasn't able to find out too much about the catalyst. The piezoelectric ignition, standard to most lighters, involves a quartz crystal which, upon being hit sharply, produces a high voltage electric discharge (a spark) which ignites the butane/oxygen mixture. i got this from a site.
Kiteman7 years ago
You need a venturi.

Have a look at a Bunsen burner - the gas enters the base of the chimney via a narrow jet and blows up the much wider chimney.

When you open the air-holes at the bottom, the venturi effect (fast fluids have lower pressure) draws air in through the holes. The gas and air mix as they flow up the chimney, giving a decent proportion of gas:oxygen.

The trick is getting all the variable balanced - the flame burns back along the jet of gas, so you need the gas to flow out as fast as it burns.

The length and diameter of the chimney will affect the burn, as will the diameter of the gas-jet, the size of the air-holes and their exact position in relation to the gas-jet.

Good luck...
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I think you're on your own there, unless you resort to google.
Pat Sowers7 years ago
Look at this. It burns at about 6000 degrees F
torch.gif