Butane gas torch

[peterd51]

Hi,

I've got several of the medium sized butane bottles used for camping stoves, about 15kg I think, does that sound about right?

Anyhow, I've been thinking of getting a gas torch to use with one of these bottles for heating/bending metal, etc. New ones seem to be around 15 to 20 pounds (Sterling) on ebay.

I did pick one up at a car boot sale a few months back for a quid or so and it has about a 40mm shroud around the nozzle, probably used by a roofer or some-such for melting tar.

The thing is it doesn't work very well. I get a big yellow flame out of it and there's no real heat, it'd take ages to warm anything up.

I currently still use the standard cooker requlator and I guess that's low-pressure, would I need to change it and if so, to what please?

Any chance it's a torch problem, ie nozzle/shroud too big?

I've wondered about adding a bit of compressed air to the back of the torch...does that sound like an idea please?

I'd probably buy a new torch eventually but I can't help feeling that it'd be a waste of money unless I get other things, like the regulator, right first.

Regards
Peter

 

[MrFluffy]

You'll need a high flow regulator to go with a torch thats of any significant size.
I have a gas air furnace here, and when I initially fired it up on propane gas bottles with a normal cooker regulator, it had a really tiny flame. When I changed the regulator out for a high flow unit, it started to work as intended.
It has two auxillary gas air torches on it too, and its own high flow low pressure air pump to supply the air side so what you propose is already in use in industry and the like, they mix inside the torch head the same as a regular oxy acetylene torch do, but the passageways and mixer chamber seem a little larger.
I can take a pic of the gas air torch head if thats of any use...

 

[MrFluffy]

Heres the bottle powered furnace during a test burn. This is on propane which burns cooler than butane (lower calorific value). Bottle size is the regular sort of knee high campervan cooker size.

 

[MrFluffy]

One last aside, I have a big gas blowlamp the same as you currently own, and it needs the highflow reg to operate correctly too...

 

[rtbcomp]

Those blue cylinders are butane, all the torches I've seen use propane which is a hotter gas.

Calor and Shell butane come in 15 Kg bottles, some others come in 13Kg.

 

[peterd51]

Hi,

Thanks for the input, I'll look out for a higher flow regulator to test it with.

I thought butane was hotter...I vaguely recall reading many years ago that you can use butane burners on propane but not vice versa as it'll burn the nozzles, etc. But I could have mixed that up in my memory!

Regards
Peter

 

[rtbcomp]

If you look round building sites you'll see roofers always use propane.

 

[peterd51]

Hi,

I recall that we used propane when I worked for BT.

The habit in winter was to arrive at work around 7.30am and before entering the building to get jobs/stores we'd go to the vans and light the gas-ring.

About 20 minutes later the van was warm and de-frosted, so we'd turn the gas off to drive to the first job.

But propane produces lots of water that sticks to the inside of the van and a hour later everything was frozen solid!

Regards
Peter

 

[MrFluffy]

Your right, butane has a slightly lower calorific value (got it aot) but the % difference isn't very much...

Fuel Calorific[MJ/kg] Heat value[MJ/kg]
Propane 50.3 46.3
Butane 49.5 45.7

The real reason that propane is used on site mostly is because it freezes at a much lower temperature...

Ive ran my torch and furnace on both, with only a change of regulator of course...

 

[shenion]

Do you guys had MAPP gas over there? Comes in 16oz bottles here.

I have a MAPP torch and it works well for freeing things. Can be used to bend steel as long as it is small, takes a while though. Also had a small MAPP/Oxy setup but the disposable oxygen cans were expensive and lasted about 10 minutes.

 

[JimM]

What sort of size steel can you bend with a propane torch ?

I've wanted to bend steel a couple of times but thought you needed the full oxy/acte setup to do it.

Would one of these torches be up to the job

http://www.machinemart.co.uk/shop/product/details/fc109-gas-torch-with-nozzles

Thanks

Jim

 

[English Steve]

MAPP gas is available here in small disposable cylinders, but I have never tried it myself - looks expensive.

A lot of Blacksmiths use propane fired forges. They usually have a simple blower in the line to increase the heat, and using firebricks to concentrate and retain the heat as in Mr Fluffy's post you should be able to get steel to a bending heat without problem. I have seen hammer-welding heats achieved with this set-up on 3/4" bar.

Steve

 

[MrFluffy]

If your careful with placement of firebricks and things to concentrate the heat, you can get most jobs to redness with just a normal blowlamp and some patience too.

 

[shenion]

MAPP gas here is about 2x the cost of disposable propane here. I think they were $8 last time I picked up one. Propane is about $3.

I picked up a Chinese O/A setup and use it with propane from a BBQ. Saves me the cost of disposables. I do have a acetylene tank also. Refills are not expensive.

Remeber, no tank rentals here, so O/A setup is cheap to have around.

I do use the MAPP torch (with both propane and MAPP tanks as needed) for things like freeing frozen nuts.

Steve is right, propane needs help to heat metal to bending. By the time the metal gets hot enough to bend, it is radiating as much heat as you put into it. Some kind of forge oven would help.

 

[MrFluffy]

If you close it off with firebricks, and play the torch over the surface, you can get some quite suprisingly large chunks of steel to bending heat with a straight torch. If the firebricks or some ceramic chips are near enough, theres nowhere really for it to radiate.

What most people do is clamp the thing in a vice and start warming, where the vice acts as a huge heatsink/radiator preventing you from standing a chance of getting it near.

If you look at the design of a small melting pot, most of them use even less strong a heat source and in fact many of them use a propane torch to melt aluminium!
The trick is the pot is thick insulation all round the business bit...

http://www.backyardmetalcasting.com/

 

[rtbcomp]

What sort of size steel can you bend with a propane torch ?

I've wanted to bend steel a couple of times but thought you needed the full oxy/acte setup to do it.

Would one of these torches be up to the job

http://www.machinemart.co.uk/shop/product/details/fc109-gas-torch-with-nozzles

Thanks

Jim

I've got one of those kits, but I doubt whether ir would get steel hot enough to bend without shielding as mentioned above.

It's great for soldering copper pipes.

Also take note of what Mr Fluffy says about holding stuff in a vice!

 

[storm monkey]

For the limited amount of heating and bending I've done, I've used my garden Chimenea (big clay pot wood burning garden heater) to get quite large bits of steel (8mm thick) up to a nice cherry red, which meant I could beat it flat again.

Phil

 

[bump]

MAPP is fairly freely available here, Mainly used by plumbers for pipe soldering.

 

[shenion]

MAPP gas torch

I have a MAPP gas torch that I think was sold by Sears:



It works well even on propane. It is different that most other torches as the burner is 7" long. There is an orifice at the valve and holes to let in air. That allows it the full length to mix. The last 2" of the tube will actually glow bright red-orange. It also makes a whistling sound

It also came with a smaller torch. It works well.