Oxy propane

[trainer]

I currently have an oxy acetylene setup.
What do I need to convert to propane? Can I use my current regulators and torches?

I understand that it's not hot enough to weld steel, but how does it perform for cutting and brazing?

 

[alfadan]

I only cut with it, but you do need tips made for propane.

 

[dscheidt]

I currently have an oxy acetylene setup.
What do I need to convert to propane? Can I use my current regulators and torches?

I understand that it's not hot enough to weld steel, but how does it perform for cutting and brazing?

No. You need new regulator, hose, and flash arrestors. Depedning on your torch, you may need different tips.

The not being able to weld with it isn't a 'not hot enough' problem, it's a flame chemistry problem. acetylene has a reducing atmosphere in the inner flame cone, propane doesn't. Or something like that, propane welds are brittle.

 

[Boilerhouse]

You can heat, cut and braze with propane. I have kicked around the idea of converting to oxy-propane myself, to save money on acetylene and avoid the inconvenience of filling that tank at a specific depot, but on another forum, a poster mentioned that propane uses more oxygen than acetylene does. So I looked into it, and indeed, propane uses about 4x more oxygen compared to acetylene. So there goes some of the cost savings and convenience. I think I will just stick with my oxy-acetelyene set up.

 

[GeoBruin]

You can heat, cut and braze with propane. I have kicked around the idea of converting to oxy-propane myself, to save money on acetylene and avoid the inconvenience of filling that tank at a specific depot, but on another forum, a poster mentioned that propane uses more oxygen than acetylene does. So I looked into it, and indeed, propane uses about 4x more oxygen compared to acetylene. So there goes some of the cost savings and convenience. I think I will just stick with my oxy-acetelyene set up.

There is the safety aspect to consider as well. No need to worry about not having a big enough acetylene bottle for a given withdrawl rate etc. I run oxy acetylene as well but have thought about propane for that reason alone.

 

[Firebrick43]

There is the safety aspect to consider as well. No need to worry about not having a big enough acetylene bottle for a given withdrawl rate etc. I run oxy acetylene as well but have thought about propane for that reason alone.

You still have to have a big enough propane bottle to vaporize the gas. Its not dangerous Per se, if the bottle is to small for the btu the bottle will freeze up(auto refrigeration) and stop drawing.

Propane will use significantly more oxygen and is slower to cut. My dads torches are propane and I hate using them. Even though acetylene is more expensive we figured it out one time and it was about a wash when you consider the additional trips to exchange cylinders.

 

[BigMike782]

Oxy acetylene mixture is 1.1 to 1 as opposed to oxy propane which is 4 to 1, that's why you cant weld.
It depends on who you ask about equipment CGA9Compressed Gas Acc) says to never change gas services on equipment but I was told by a 30 yr Victor rep that the difference between an acetylene regulator and a propane regulator is the spring and the delivery side gauge.
If I were going to switch I would get the correct cutting tip and go for it.

One word of caution, using an acetylene regulator on propane should not cause issues but NEVER use a propane regulator on acetylene. The propane regulator has the ability to deliver pressure over 15psi and acetylene is very unstable above 15psi.

 

[pete379]

i have been using oxy-propane for 43 years mainly cutting - hand torch and machine torch- occasionally heating. regulator set is standard oxy-ace set from victor. propane tips are 2 piece. i set pressures as advised in my victor cutting booklet, cuts are just as clean as acetylene

 

[alfadan]

I guess one thing to consider is no lease on a propane tank and can get it filled more places that are open later than gas suppliers

 

[rlitman]

No. You need new regulator, hose, and flash arrestors. Depedning on your torch, you may need different tips.

No, you do NOT need a new regulator or new flash arrestors or check valves (I'll explain the hose question below). Any acetylene regulator can be safely used with propane. If your regulator happens to have a POL CGA-510 fitting, it will work directly with a propane cylinder. If it is CGA-300 style regulator, you will need an adapter (usually you get adapters to go the other way though). If you have a CGA-200 (MC) or CGA-520 (B) regulator, do yourself a favor and get a real regulator. It is important to understand that the material components inside both acetylene and propane regulators are all the same, so propane will not damage an acetylene regulator and vice versa, even though regulators are sold specifically for these two gases.

As for other acetylene/propane gas cross compatibility issues, it's been covered here many times, but I'll rehash what you need to know.

Acetylene regulators have gauges that stop at 15 PSI output. The regulator may go higher, but the gauge is just a red bar above 15, because that high pressure is unsafe with acetylene. Output pressures above 15 PSI are perfectly safe with propane, so a dedicated propane regulator will have a gage that goes to 30 PSI (or more), but outside of some gigantic heating tips you simply will not have need for so much pressure. You certainly do not need that much pressure for cutting or brazing.

Check valves and flash arrestors will all be cross compatible with most fuel gases. Hydrogen MAY be the only exception, just because ordinary sintered metal flashback arrestors are insufficient to stop a flashback with hydrogen so people usually resort to bubblers, but even then, it isn't as if hydrogen will damage these components, so if you have a torch with them integrated (which I'd usually recommend) feel free to use it with any fuel gases you want.

Regarding hoses. Grade "T" hoses are compatible with ALL fuel gases. Acetylene, propane, you name it. Grades R and RM are ONLY compatible with acetylene (R is plain rubber, and RM has an oil resistant outer layer, but the interior is still rubber). Other fuels will degrade the rubber found in grades R and RM hoses, and because the issue starts on the inside, you will not have any visible signs of a problem until the hose fails.

Acetylene cutting and heating tips have a flat front surface with holes for the mixed gases piercing it. Propane cutting and heating tips have this pierced surface recessed a little. You can convert acetylene cutting or heating tips to work with propane by pressing on a ring cut from copper pipe* to protect the base of the flames. Or you can just buy propane cutting or heating tips. Single hole brazing tips are compatible with both types of gases.

*Pure copper is dangerous around acetylene, so don't use your converted tips again with acetylene unless you remove the copper.

One thing you WILL need new are shades. Oxy-acetylene flames are very bright, and you need a shade 5 lens when working with O/A to protect your eyes from their white light. Oxy-propane burns much cleaner, and you will quickly discover that it is impossible to spot the central cone of an oxy-propane flame through shade 5 lenses, so you will want something close to shade 2 (dark sunglasses) to be able to adjust yourself to a neutral flame. Also, oxy-propane does not produce a "feather", so expect the flame to look weird until you get used to it. The problem here though is sodium flare. That bright orange flare you get off of flux while brazing may be too bright for shade 2 lenses, and that's why I gave up on trying to use oxy-propane with brazing (it is fine for flux-less silfos brazing and cutting though).

 

[MoonRise]

Torch body can usually be used for either acetylene or propane. RTFM or call/check with your torch manufacturer.

Regulators can usually be used if you adjust the CGA connections to match between the regulator and the cylinder, but the acetylene regulator has a different pressure regime than a propane one. It will 'work', but might not be able to deliver the needed pressure for some heating/cutting applications. Easiest is to just get a new regulator for use with propane.

NEVER use a propane regulator with acetylene!!!! There's a very good safety reason that an acetylene regulator only goes up to 15 psi delivery pressure (in the green/safe zone).

You will need to get oxy-propane tips, cutting or heating. The burning characteristics are different between acetylene and propane, hence different tips for the different gases.

You will NEED to get Grade T hoses (if you do not already have them). The 'standard' acetylene-only Grade R or RM hoses will degrade/fail if used with alternate fuels like propane.

You will go through oxygen 4x with oxy-propane as much compared to oxy-acetylene (not counting oxy-fuel cutting, where the majority of the oxygen use is in the oxygen cutting jet and not the oxygen used for the preheat flame).

 

[rmack898]

No, you do NOT need a new regulator or new flash arrestors or check valves (I'll explain the hose question below). Any acetylene regulator can be safely used with propane. If your regulator happens to have a POL CGA-510 fitting, it will work directly with a propane cylinder. If it is CGA-300 style regulator, you will need an adapter (usually you get adapters to go the other way though). If you have a CGA-200 (MC) or CGA-520 (B) regulator, do yourself a favor and get a real regulator. It is important to understand that the material components inside both acetylene and propane regulators are all the same, so propane will not damage an acetylene regulator and vice versa, even though regulators are sold specifically for these two gases.

As for other acetylene/propane gas cross compatibility issues, it's been covered here many times, but I'll rehash what you need to know.

Acetylene regulators have gauges that stop at 15 PSI output. The regulator may go higher, but the gauge is just a red bar above 15, because that high pressure is unsafe with acetylene. Output pressures above 15 PSI are perfectly safe with propane, so a dedicated propane regulator will have a gage that goes to 30 PSI (or more), but outside of some gigantic heating tips you simply will not have need for so much pressure. You certainly do not need that much pressure for cutting or brazing.

Check valves and flash arrestors will all be cross compatible with most fuel gases. Hydrogen MAY be the only exception, just because ordinary sintered metal flashback arrestors are insufficient to stop a flashback with hydrogen so people usually resort to bubblers, but even then, it isn't as if hydrogen will damage these components, so if you have a torch with them integrated (which I'd usually recommend) feel free to use it with any fuel gases you want.

Regarding hoses. Grade "T" hoses are compatible with ALL fuel gases. Acetylene, propane, you name it. Grades R and RM are ONLY compatible with acetylene (R is plain rubber, and RM has an oil resistant outer layer, but the interior is still rubber). Other fuels will degrade the rubber found in grades R and RM hoses, and because the issue starts on the inside, you will not have any visible signs of a problem until the hose fails.

Acetylene cutting and heating tips have a flat front surface with holes for the mixed gases piercing it. Propane cutting and heating tips have this pierced surface recessed a little. You can convert acetylene cutting or heating tips to work with propane by pressing on a ring cut from copper pipe* to protect the base of the flames. Or you can just buy propane cutting or heating tips. Single hole brazing tips are compatible with both types of gases.

*Pure copper is dangerous around acetylene, so don't use your converted tips again with acetylene unless you remove the copper.

One thing you WILL need new are shades. Oxy-acetylene flames are very bright, and you need a shade 5 lens when working with O/A to protect your eyes from their white light. Oxy-propane burns much cleaner, and you will quickly discover that it is impossible to spot the central cone of an oxy-propane flame through shade 5 lenses, so you will want something close to shade 2 (dark sunglasses) to be able to adjust yourself to a neutral flame. Also, oxy-propane does not produce a "feather", so expect the flame to look weird until you get used to it. The problem here though is sodium flare. That bright orange flare you get off of flux while brazing may be too bright for shade 2 lenses, and that's why I gave up on trying to use oxy-propane with brazing (it is fine for flux-less silfos brazing and cutting though).

^^^^^^^^^^^^^^^^^^^ rlitman has it covered.

I made the switch to propane over 30 years ago because it reduced my commercial insurance by a sizable amount by not having acetylene in the shop.

 

[rlitman]

...I made the switch to propane over 30 years ago because it reduced my commercial insurance by a sizable amount by not having acetylene in the shop.

Really? Propane can pool in buildings (acetylene is lighter than air and rises), so something as small as a 20lb BBQ cylinder isn't allowed indoors, while reasonably small acetylene cylinders are fine. If anything, it's the oxygen cylinder that presents the most dangers, so I do wonder what your insurance was thinking.

 

[setfocus]

I've read that you can't braze or torch weld with propane. I guess burnt acetylene gas acts as a shielding gas, where as propane doesn't. So the welds will always be **** with propane. That said, I'm a welding novice at best and I've never tried to weld with propane.

Also heard oxy propane burns a bit hotter than oxy acetylene.

 

[rlitman]

I've read that you can't braze or torch weld with propane. I guess burnt acetylene gas acts as a shielding gas, where as propane doesn't. So the welds will always be **** with propane. That said, I'm a welding novice at best and I've never tried to weld with propane.

Also heard oxy propane burns a bit hotter than oxy acetylene.

Oxy-acetylene is hotter. You certainly can braze with oxy-propane. As for the flame chemistry, it can be difficult to get to a neutral flame with oxy-propane, because the cone borders are nearly invisible in daylight.

 

[ItsNemo]

I've read that you can't braze or torch weld with propane. I guess burnt acetylene gas acts as a shielding gas, where as propane doesn't. So the welds will always be **** with propane. That said, I'm a welding novice at best and I've never tried to weld with propane.

Also heard oxy propane burns a bit hotter than oxy acetylene.

Not that it burns hotter in terms of actual temperature, but propane has more BTU so you have more total heat.

 

[Earp69]

I switched from oxy/acet to propane/acet and am glad I did.

 

[ItsNemo]

I switched from oxy/acet to propane/acet and am glad I did.

Oh boy, that must be an interesting mix LOL

 

[GeoBruin]

Really? Propane can pool in buildings (acetylene is lighter than air and rises), so something as small as a 20lb BBQ cylinder isn't allowed indoors, while reasonably small acetylene cylinders are fine. If anything, it's the oxygen cylinder that presents the most dangers, so I do wonder what your insurance was thinking.

Forgive me if I'm telling you something you already know but other readers of the thread might not know about the instability of acetylene at high pressures. I don't know all the details but from what I understand, it must be stored in a cylinder with a special matrix soaked with acetone. If a bottle gets tipped/knocked over, or if the withdraw rate gets too high for the bottle size, the acetone itself can be withdrawn through the hose/torch, reducing the ratio of acetone to acetylene gas to the point where thr bottle becomes unstable and could... combust? Explode? I'm not totally sure of the consequences.

Anyhow, it just seems that there is more care required when using acetylene than propane which probably half of Americans use routinely with their grills without (many) incidents.

 

[welder4956]

We had this discussion at work many times. The heat content of propane is much less than acetylene, so you wind up using more propane cylinders than you would with acetylene for the same amount of work. The gas cylinder salespeople periodically tried to get us to convert to propane, but our total cost would have actually increased and it takes longer to do the same work. Do your homework to make sure it makes economic sense for you before making the switch.

 

[ItsNemo]

We had this discussion at work many times. The heat content of propane is much less than acetylene, so you wind up using more propane cylinders than you would with acetylene for the same amount of work. The gas cylinder salespeople periodically tried to get us to convert to propane, but our total cost would have actually increased and it takes longer to do the same work. Do your homework to make sure it makes economic sense for you before making the switch.

This is wrong, the heat content (BTU) of propane is higher. Flame temp is higher with acetylene, but you can actually put more heat into the work piece with propane. As stated above, you use more oxygen, but propane itself is a cheaper fuel to run than acetylene.

 

[rmack898]

Really? Propane can pool in buildings (acetylene is lighter than air and rises), so something as small as a 20lb BBQ cylinder isn't allowed indoors, while reasonably small acetylene cylinders are fine. If anything, it's the oxygen cylinder that presents the most dangers, so I do wonder what your insurance was thinking.

My insurance was through Lloyd’s of London. They didn’t even like my B bottle turbo torch. Was almost $1K cheaper to get rid of acetylene.

 

[welder4956]

This is wrong, the heat content (BTU) of propane is higher. Flame temp is higher with acetylene, but you can actually put more heat into the work piece with propane. As stated above, you use more oxygen, but propane itself is a cheaper fuel to run than acetylene.

Thanks for clarifying my recollection. I knew it was something like that. So they really wanted us to use propane so they could sell more oxygen cylinders. We had such good performance with acetylene for cutting and heating, that we could not see a real benefit to switching even if the fuel gas cost was slightly lower.

 

[rlitman]

Oh boy, that must be an interesting mix LOL

propane/acet is too rich for me.

Forgive me if I'm telling you something you already know but other readers of the thread might not know about the instability of acetylene at high pressures. I don't know all the details but from what I understand, it must be stored in a cylinder with a special matrix soaked with acetone. If a bottle gets tipped/knocked over, or if the withdraw rate gets too high for the bottle size, the acetone itself can be withdrawn through the hose/torch, reducing the ratio of acetone to acetylene gas to the point where thr bottle becomes unstable and could... combust? Explode? I'm not totally sure of the consequences.

Anyhow, it just seems that there is more care required when using acetylene than propane which probably half of Americans use routinely with their grills without (many) incidents.

I brushed over it, but yes, acetylene regulators "stop" at 15 PSI, because with enough pressure acetylene can break down explosively without even the presence of an oxidizer. Propane surely doesn't have any risks like that.

 

[KenC]

We used Propane/O2 from 1960 til 2000 cutting only in the auto salvage. Dad retired but I still have the torches. Normal acetylene and O2 regulators. Special tip for the torch.

Started with acetylene in 60 and quickly changed over due to the cost difference. I haven't done the calculations recently, but with the high price of acetylene now, O2 usage, even at 4 times the rate would still be a good deal.

Another thing I've noticed, propane produces less slag on the bottom of the cut for me.

I have a big bottle cart with a propane bottle, O2 bottle and acetylene. The fuel regulator gets swapped according to the need. Weld/braze with the expensive gas, cut with propane.