View Full Version : acetylene torch

jim davies
06-04-2004, 12:25 AM
I have an oooold air-acetylene torch I got from an uncle. It works well on acetylene, but I woould like to try it on propane. Needless to say, just hooking it up doesn't work. I suppose I could adjust the orifice size. Anybody know what difference in size might work? eg larger or smaller and approximately how much...

G.A. Ewen
06-04-2004, 12:45 AM
Sorry I don't think that it will work no mater what you try.

06-04-2004, 01:01 AM
That's all the salvage yard down here uses--Propane and Oxygen so I know it WORKS. They cut 2" plate and huge rounds all the time.

If you're talking about propane only, it won't work unless you put an air mixer on the front. (Like the propane torches) Orifice size? What do you mean? The tip? See previous sentence.

The mixer is nothing more than a tube over the tip that draws air from the backside. The vortex created by the propane draws the air in. This method only works up to about 7psi. After that, you'll need such a large mixer tube it wouldn't be practical for use.

06-04-2004, 01:03 AM
Congratulations Jim,

An Oxy/Acetyline setup is one of the most useful tools you can have in the shop. You should give up that idea of using it as a propane torch. Someone else can help you with the technical differences but I don't think you will be able to reach the higher temperatures with propane. In cutting it is the oxygen that burns the metal away so don't give up on that.

Don't try to re-invent the wheel and you'll be happy. You might need some new tips and other things and I've tried to learn from books but I think a class would probably be great.

Have fun and be careful.


Forrest Addy
06-04-2004, 01:18 AM
Before you try that oxy acetylene torch on propane consider that the fuel gasses have considerably different properties.

If you can find propane tips for the cutting torch it will work well. Burning propane in an acetylene tip won't give you enough pre-heat.

I'm as cheap as they come. I started with oxy-propane in 1963 using all the right tips and procedure. After beating my head against the wall and not being able to make quality gas welds in that time I bit the bullet and went to acetyene. The question is not if but when you decide for acetylene and how much being stubborn will cost you in propane equipment.

I paid for a 220 cu ft oxy tank and a 250 cu ft acetylene in in 1964. In all that time all I've had to do is trade them in for full ones. 40 years of paying only for gases - no demurrage, no test charges. One of the best investments I ever made and my oxy-acety outfit has made me thousands over the years.

I still have some Airco propane tips. Anyone want a bargain?

06-04-2004, 03:00 AM
He said an AIR-acetylene torch, not oxy-acetylene.

A quick search revealed the following:



06-04-2004, 03:06 AM
Guys, PAY ATTENTION! George has it right. Jim said "Air/Acetylene". That is NOT oxy/ acetylene. I used to have one of those torches for jewlery making. It won't work on propane. You might as well buy a standard propane bottle torch. The usable mixture ratio for air/acetylene is far wider than for air/propane and a torch designed for air/acetylene won't work with propane. The stoichiometric mixture ratio is entirely different.

Jim, the mixture ratio for propane is fairly critical. Unless you have several spare jets for the torch you will probably ruin it trying to change the orfice size. It will be a trial and error effort and if you try it then go up the smallest increment you can drilling out the orfice. For propane it needs to be richer.

jim davies
06-04-2004, 08:11 PM
Thanks for the input everyone. I know the tradeoffs from using propane instead of acetylene and I have a complete oxy-acetylene set for my shop, and several sets at work. I don't really want to use acetylene
at my own shop for several reasons but would like to have something a bit better than a bernzomatic. I'll have another look at the torch and see if the orifice is easily removed and if so maybe i'll make a new one and try various sizes. I don't want to screw it up, it's a mint prest-O-Lite that is probably 50 years old.

06-04-2004, 11:25 PM
Sorry guys. I recognised my error right after I posted. That's when I found out that you CAN'T delete your own message.

Neal! Please let me delete my own messages.

This is sooo much better than OPEN mouth INSERT foot.


06-05-2004, 08:47 AM
You may be able to get the Prestolite torch to burn Propane, but why bother.
If you have acetylene available, use that, you will get more heat.
Propane, like any fuel gas, has a specific BTU content, and even if you can manage to get it to burn in the Prestolite, you will still get no more heat than available from the Bernzomatic.

Forrest Addy
06-05-2004, 09:10 AM
Air acetylene! D'oh!!

Sorry guy. Knee jerk overwhelmed me.

06-05-2004, 07:40 PM
Just as a side note,I keep everything laying around to burn whatever is lying around when I need to.On my home setup I got two Ox cylinders leased and keep propane on it,reason being I can get them filled on the weekend if need be.Plus my forge and furnace as well as bbq run off it too.

06-06-2004, 03:17 PM
You can, or at least could at one time, get a "swirl jet" tip for propane that will fit a Prestolite torch handle. Mine is about 20 years old and came from a welding supply dealer that carries Union Carbide Welding Products. They are available in several sizes and you just unscrew the acetylene tip from the handle and replace it with the propane tip. You don't have as much control over flame size with it as you do with acetylene, since the propane tip needs to run at or near full blast to prevent the flame from touching the side walls and overheating it.