Cutting Torch Question

rgood · 10-12-2007, 12:31 AM

Hi,

I know that some cutting torches run on Acetylene and some run on Propane.

I also know at a certain pressure Acetylene can be very dangerous - It can cause an explosion.

If I use propane in a cutting torch, at what pressure range is it usually used and at what pressure is it dangerous?

Thanks

GuglioLS · 10-12-2007, 01:25 AM

Acetylene should never be run at any pressure over 15 PSI MAX. AND never use Copper fittings or Copper pipe with Acetylene gas. Only brass with less that 40% copper is allowed.

I've never seen a propane cutting torch.

Larry

mjncad · 10-12-2007, 01:36 AM

This may not be oxy-propane; but it is different. Petrogen | Petrogen Oxy-Gasoline Cutting Systems Home Page

bigdad · 10-12-2007, 05:31 AM

I have used propane on the railroad and it requires a different setup on your torch head and tip. I personally didn't think that it got as hot but it's much cheaper if all you do is cut. Though I never tried it, I was told that you can't braze with it. I still use Acetylene at home because from time to time I'll braze something. I sure don't like buying it! (Acetylene) $$$

BD

cattoon · 10-12-2007, 09:14 AM

propane is all I use to cut with. need a new tip specifically for propane. and I think I run my propane at about 7 psi and oxygen at 21 I want to say oxygen needs to be 3 times propane pressure. cuts good for my uses and I always have propane at home. But it is amazing how long a tank lasts the O2 will run out long before the fuel

AlanB · 10-12-2007, 09:22 AM

Acy runs about 5 PSI in use (flowing)

If you want to see an Oxy Propane if you have a local scrap yard, that is probably what they are using. For lots and lots of straight forward (but usually rather crude) cutting, it is the most efficient.

turnkey4099 · 10-12-2007, 02:09 PM

Just wondering. Talking propane torching. Is it the same as MAP gas. That is a very good torch fuel (don't know about brazing) and cheap compared to acetyline.

Harry K

midcarolina · 10-12-2007, 03:00 PM

Have you considered a plasma machine? the prices have came way down.

the cut is much cleaner ( means less cleanup on the cut material )

The initial cost is more but the savings on the consumables, gas, oxy, grinding disks is much less in the long run

shaley · 10-12-2007, 04:16 PM

MAPP gas is Methylacetylene-Propadine. It can be used for heating, brazing, metalizing, soldering, flame hardening and cutting. Mapp gas produces a flame temperature of 5301° F (2927° )
Propane produces a lower flame temperature than acetylene (the maximum flame temperature in oxygen is 2,828°C compared with 3,160°C for acetylene).
Propane is heavier than air so we don't use it much in ship building aroung here.

rgood · 10-12-2007, 06:14 PM

Thanks for the replies - Is there a pressure at which propane is dangerous?

10-12-2007, 12:31 AM	#1 (permalink)
rgood Silver Member Join Date: Aug 2007 Location: FL panhandle Posts: 181	Cutting Torch Question Hi, I know that some cutting torches run on Acetylene and some run on Propane. I also know at a certain pressure Acetylene can be very dangerous - It can cause an explosion. If I use propane in a cutting torch, at what pressure range is it usually used and at what pressure is it dangerous? Thanks

10-12-2007, 01:25 AM	#2 (permalink)
GuglioLS Platinum Member Join Date: Feb 2005 Location: Edgewood, NM USA Posts: 876	Re: Cutting Torch Question Acetylene should never be run at any pressure over 15 PSI MAX. AND never use Copper fittings or Copper pipe with Acetylene gas. Only brass with less that 40% copper is allowed. I've never seen a propane cutting torch. Larry __________________ There is no problem that cannot be solved with the use of high explosives

10-12-2007, 01:36 AM	#3 (permalink)
mjncad Platinum Member Join Date: Aug 2006 Location: Front Range of Colorado Posts: 864	Re: Cutting Torch Question This may not be oxy-propane; but it is different. Petrogen \| Petrogen Oxy-Gasoline Cutting Systems Home Page __________________ Measure it with a micrometer, mark it with chalk, cut it with a torch, beat to fit, paint to match, inspect it with a microscope. Added sprayer modifications gallery. 07/06/2008 http://picasaweb.google.com/mjncad/FIMCOSprayer Added second camera to Lights, Camera, ACTION! & Thumper needs new teeth to John Deere L130 galleries. 06/11/2008 http://picasaweb.google.com/mjncad/LightsCameraACTION http://picasaweb.google.com/mjncad/JohnDeereL130Misc http://picasaweb.google.com/mjncad

10-12-2007, 05:31 AM	#4 (permalink)
bigdad Gold Member Join Date: Feb 2006 Location: West Central Illinois Posts: 304	Re: Cutting Torch Question I have used propane on the railroad and it requires a different setup on your torch head and tip. I personally didn't think that it got as hot but it's much cheaper if all you do is cut. Though I never tried it, I was told that you can't braze with it. I still use Acetylene at home because from time to time I'll braze something. I sure don't like buying it! (Acetylene) $$$ BD

10-12-2007, 09:14 AM	#5 (permalink)
cattoon Member Join Date: Jun 2004 Location: N.W. Alabama Posts: 28	Re: Cutting Torch Question propane is all I use to cut with. need a new tip specifically for propane. and I think I run my propane at about 7 psi and oxygen at 21 I want to say oxygen needs to be 3 times propane pressure. cuts good for my uses and I always have propane at home. But it is amazing how long a tank lasts the O2 will run out long before the fuel

10-12-2007, 09:22 AM	#6 (permalink)
AlanB Veteran Member Join Date: Jan 2004 Location: Clarksville, TN, USA Posts: 1,958	Re: Cutting Torch Question Acy runs about 5 PSI in use (flowing) If you want to see an Oxy Propane if you have a local scrap yard, that is probably what they are using. For lots and lots of straight forward (but usually rather crude) cutting, it is the most efficient.

10-12-2007, 02:09 PM	#7 (permalink)
turnkey4099 Platinum Member Join Date: Jan 2002 Location: SE Wa Posts: 873	Re: Cutting Torch Question Just wondering. Talking propane torching. Is it the same as MAP gas. That is a very good torch fuel (don't know about brazing) and cheap compared to acetyline. Harry K

10-12-2007, 03:00 PM	#8 (permalink)
midcarolina Member Join Date: May 2007 Location: Lexington,SC Posts: 30	Re: Cutting Torch Question Have you considered a plasma machine? the prices have came way down. the cut is much cleaner ( means less cleanup on the cut material ) The initial cost is more but the savings on the consumables, gas, oxy, grinding disks is much less in the long run

10-12-2007, 04:16 PM	#9 (permalink)
shaley Platinum Member Join Date: Jan 2002 Location: Tidewater VA. Posts: 676	Re: Cutting Torch Question MAPP gas is Methylacetylene-Propadine. It can be used for heating, brazing, metalizing, soldering, flame hardening and cutting. Mapp gas produces a flame temperature of 5301° F (2927° ) Propane produces a lower flame temperature than acetylene (the maximum flame temperature in oxygen is 2,828°C compared with 3,160°C for acetylene). Propane is heavier than air so we don't use it much in ship building aroung here. __________________ Steve... "My biggest fear is that when I'm gone my wife will sell all my tractor gear for what I said I paid for it. "

10-12-2007, 06:14 PM	#10 (permalink)
rgood Silver Member Join Date: Aug 2007 Location: FL panhandle Posts: 181	Re: Cutting Torch Question Thanks for the replies - Is there a pressure at which propane is dangerous?

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