View Full Version : Can you use acetylene regulator for propane?

07-11-2010, 01:10 PM
Hey, I went through this forum and searched and I am getting conflicting answers. Some say you can use a acetylene regulator for propane, others say you need the dedicated propane regulator.
Which one is ok?
Its not worth it to me to blow me and my house up over a regulator.

07-11-2010, 01:22 PM
I have used my acetylene regulator on propane for over 10 years. I have had no problems.
Are you sure your not thinking about CO2 and C25 regulators if so there is a difference.

07-11-2010, 01:31 PM
Yeah I was just making sure the propane gas wouldnt mess up the seals inside the acetylene reg.

07-11-2010, 01:56 PM
There are so many of these propane questions that it IMO merits a sticky with a comprehensive how-to. :)

I find propane quite handy, and ideal for salvage yard work since it's safer than acetylene. (No overdraw issues with small propane tanks, no acetone risks from sloshing.)

Acetylene regulators sometimes have lower output pressure ranges than propane, but this poses no problem for most use. Victor 450-series regulators and some others have stainless-steel diaphragms and use the same seat part numbers for acetylene and propane, so it's incapable of damaging them. (Thanks to OADoctor on Weldingweb for that tip, confirmed by downloading the manuals from Thermadyne.)

All common regulators have their part numbers available online, if you want to to check yours. The Seal-Seat catalogs cover most common makes.

Technically, T-rated hose is to be used instead of R-rated, but countless people have used R with no ill effects. Any dried-out/cracked/deteriorated welding hose should be cut up and disposed of immediately, but that's standard.

Its not worth it to me to blow me and my house up over a regulator.

I agree, which is one reason ALL my welding cylinders live outdoors. Even with the right stuff, properly maintained, I see zero reason to add risk to self or first responders in the event of a residential fire, welding-related or not. My welding cylinders will stay on my welding trailer, outdoors, where any leakage (defective cylinder valves happen, it needn't be a regulator failure) will be gone with the wind.

07-11-2010, 02:16 PM
From what I gather, going the other way might be a problem. In other words, a propane reg might not have the correct seals to withstand the acet or the acetone. I suspect that might be more of a problem with older regs.

07-11-2010, 03:24 PM
Acetylene standard valve fitting is CGA-510 outlet fitting.
Acetylene 10 cubic foot MC cylinder MC uses CGA-200 outlet fitting.
Acetylene 40 cubic foot B cylinder uses CGA-520 outlet fitting.
Western Enterprises sells adapters from CGA200 or CGA520 to CGA510.

Acetylene explosive limits in air 2.5 to 80%.
Propane explosive limits in air 2.2 to 9.5%.

Propane 20 pound cylinders through 100 pound cylinders can accept regulators with CGA-510 inlet fitting. Adapters are available to use regulators with CGA200 and CGA 520 fittings on valve with CGA510 fitting.

Acetylene low pressure gage has warning about setting regulator above 15psi because Acetylene is unstable and can explode above 15psi. Propane does not have this stability issue and can use higher LP pressure.

Propane regulator LP pressure gage indicates up to 250 psi.

Acetylene Hoses are made of layers of rubber or neoprene with braided reinforcement. VD grade RM hose is for acetylene and T grade hose with neoprene inner is for all fuel gases. Many have reported using RM hose without problems with propane. If I was using propane every day all day would only use T grade hose. More expensive T grade is better but outer wear and wear at hose fittings will most likely be cause for hose replacement.

Victor uses neoprene diaphragms both their propane and acetylene regulators. All of their acetylene regulators are rated for use with propane. If your worried about it ask your regulator manufacture if your acetylene regulator is ok for use with propane.

Most common regulator failure with age is pressure creeps slowly higher than set pressure. You would see this with torch valves closes. But it is normal for regulator pressure to creep up a little as torch valves are closed because the pressure increase is used to close regulator valve. As regulator is used gas erodes groove in orifice causing more regulator creep before gas flow stops or even a free flow. This can be very dangerous with acetylene.

Diaphragm leaks can be heard or smelled if it is propane or acetylene leak. Leak test solution at diaphragm vents will bubble indicating leak. Leaking diaphragm can reduce ability to regulate pressure.

I would use any Acetylene regulator that was working properly with propane. Neoprene diaphragms and seals are commonly used with both gases and are cheapest compatible material for either gas.

07-12-2010, 03:57 PM
I can tell you my experience - I have used both Acetylene and propane since the the sixty's - I have never had a problem swapping Acetylene to propane reg
As far as the hoses go well on one of the trks three of the four hoses have been on there since 1990 . Hoses are not cracked , are still pliable in fact show no signs of there age ( propane on the trks - Acetylene in the shop)
- hoses are the R
Thats just my experience you should do what you think is right

05-27-2011, 01:52 PM
Bumping this back to the top. Are the regulator pressure settings the same for using propane as acetylene or different?

05-28-2011, 08:44 AM
Bumping this back to the top. Are the regulator pressure settings the same for using propane as acetylene or different?

If you go to the Smith site they have a chart of pressure recommendations for a particular application.
When I switched over to propane from acetylene I use about 5 lbs more regulated line pressure as I did before the switch over (11-12 years ago) no problems.