Propane Welder/Generator

clee4020 · Aug 28, 2012

Want a portable (trailer mounted) welder to use on the farm. Also want a back-up generator for the house. I know diesel Welder/Generator are around twice the purchace price of a gas burner and you can only keep gas stock piled so long. Seems like I could ad a tee and cutoff valve from my 250 gal propane tank at my house and always have back-up power. I haven't priced them and would like to know which is more efficent and any other pros and cons of a propane Welder/Generator?

Shield Arc · Aug 28, 2012

About 12-years ago I bought a 10,000-watt generator, bought an after market propane conversion kit, I can run it on the 20-lb bottles or the 300-lb tank out front.

If I wanted a welder / generator combination I would buy one of these. A very good friend of mine has the non propane version, fantastic welder!

Rangerｮ 305 LPG Engine Driven Welder (Kohler)

clee4020 · Sep 5, 2012

Anyone used a propane Welder/Generator as a welder? Any noticeable difference in the welds between that and same model in a gas burner or diesel? I know propane is supposed to burn cleaner, but how efficent are they?

Shield Arc · Sep 5, 2012

I have used a couple small welders that were propane powered. I think they were Miller Bobcats, then again this was over 30-years ago, welding conveyors together inside the airport. To be honest I'm not a real big fan of the Bobcat welder in the first place, but being propane powered, I did not notice any difference at all.
I have heard, than you lose a little horse power when switching to propane, don't know how true that is.

Zork · Sep 7, 2012

I am assuming the LP is for the engine. Looks like a great deal to me for $1950

Miller Welder

Mickey_Fx · Sep 7, 2012

Propane has considerably less energy content and gasoline. Fuel consumption will be up. Know over in the RV world, those that have propane powered gensets typ wouldn't go that way again if they had the choice. Limited supply of propane and high fuel usage. They also need the propane for the frig and stove/heater.

Additionally, what the lowest outside temp you'd expect to see while running this? The rate of vaporization of propane is tied closely to temp. Getting down to freezing you likely couldn't run this off of small portable bottles.

firedog · Sep 13, 2012

clee4020 said:
Want a portable (trailer mounted) welder to use on the farm. Also want a back-up generator for the house. I know diesel Welder/Generator are around twice the purchace price of a gas burner and you can only keep gas stock piled so long. Seems like I could ad a tee and cutoff valve from my 250 gal propane tank at my house and always have back-up power. I haven't priced them and would like to know which is more efficent and any other pros and cons of a propane Welder/Generator?

That is exactly what I did. Mine's not trailer mounted, but I can easily move it with the front end loader. It is a Lincoln gas machine that I converted for bifuel operation. True that LPG has about 75% of the energy content of gasoline, but I haven't noticed a big difference when using it as a generator. I tapped the LP line behind my shop where my transfer switch is also. I can run for several days on 500 gal of LP. I live on the Texas coast and during hurricane power outages gasoline can be hard to come by. LP has been much easier to get.

A machine thats LP from the start will give you full power because the engine is sized for LP use. But your limited to only using LP. With the conversion kit, you can swap back to gas for any remote welding job. I haven't regretted it for one second.
Here's a couple of folks that sell conversion kits:
Generator Propane Conversion Kits & Natural Gas Conversions
Generator Conversion Kits to Propane and Natural Gas.

msb1766 · Sep 13, 2012

Propanes octane rating is 110

firedog · Sep 14, 2012

msb1766 said:
Propanes octane rating is 110

True enough, however, octane ratings are not indicators of the energy content. It is only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. The actual power output of an engine running on LPG vs Gasoline varies based on the characteristics of the engine, carburetor, air temp. & density, among other things.
The energy content is an easily quoted number, but may not give a true rating of engine output.
Things like the particular engine and carb efficiency, the energy content of the fuel, the fuels rate of burning (octane rating), how the fuel disperses, fuel & air densities brings us to a very complex formula of stoichiometric combustion (Wow, that's a big word.)
In my personal experience, I think that the LPG can deliver much higher engine output that 75% of gasoline, but I don't know exactly where it falls since I don't have precise method to measure it. (other than hook it up and go. gut feeling - 85-90% maybe)

clee4020 · Sep 18, 2012

firedog said:
That is exactly what I did. Mine's not trailer mounted, but I can easily move it with the front end loader. It is a Lincoln gas machine that I converted for bifuel operation. True that LPG has about 75% of the energy content of gasoline, but I haven't noticed a big difference when using it as a generator. I tapped the LP line behind my shop where my transfer switch is also. I can run for several days on 500 gal of LP. I live on the Texas coast and during hurricane power outages gasoline can be hard to come by. LP has been much easier to get.

A machine thats LP from the start will give you full power because the engine is sized for LP use. But your limited to only using LP. With the conversion kit, you can swap back to gas for any remote welding job. I haven't regretted it for one second.
Here's a couple of folks that sell conversion kits:
Generator Propane Conversion Kits & Natural Gas Conversions
Generator Conversion Kits to Propane and Natural Gas.

After doing some reasearch about coverting them to LP, some of the stuff I read suggested that you leave on LP unless you wanted engine trouble. How much do you run yours on gasoline? I assume you haven't had anytroule with yours. I may have been mis-informed and if you could swith back to gasoline when needed would be great. Anyway, if I bought an LP machine, I would mount 2, 33 lb tanks on the trailer. When 1 went empty, I'd hook up the second one and know that I need to get the first filled. Not sure how long I could weld or run generator off a 33 lb tank.

firedog · Sep 18, 2012

I've never had any problems with switching back and forth. In fact, I've heard that you need to run on gasoline now & then to keep the o-rings & seals from drying out. who knows.
The LP enters at a venturi that is installed at the opening of the carb. My smaller generator (5500w) has no problems pulling off a 30# cylinder, but the welder/generator (10,000w 20hp) wont. The LP cylinders have an excess flow check valve that shuts off.