CO2/Argon 5%, 10%, 15% ?? When? Why?

To add just a bit to what General Zod said, 75/25 (argon/Co2) is very common for short-circuit MIG, but if you want to get into spray transfer MIG, you need a higher percentage of argon. Here in the States that usually means 90/10, 95/5 or 98/2. Not all welders have enough power to get into spray transfer mode, so it may not even be an option for you.

Using a MIG welder with a spool gun or push/pull gun for aluminum requires 100% argon.

Using a MIG welder for stainless steel requires one of several blends....helium/argon/Co2, argon/O2 or argon/Co2.

TIG requires 100% argon, or an argon/helium blend.
 
G-ManBart said:
To add just a bit to what General Zod said, 75/25 (argon/Co2) is very common for short-circuit MIG, but if you want to get into spray transfer MIG, you need a higher percentage of argon. Here in the States that usually means 90/10, 95/5 or 98/2. Not all welders have enough power to get into spray transfer mode, so it may not even be an option for you.

Using a MIG welder with a spool gun or push/pull gun for aluminum requires 100% argon.

Using a MIG welder for stainless steel requires one of several blends....helium/argon/Co2, argon/O2 or argon/Co2.

TIG requires 100% argon, or an argon/helium blend.
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You guys are just great! A beginner could go for quite a long time without discovering stuff like this. Thank you all!
 
graham-xrf said:
You guys are just great! A beginner could go for quite a long time without discovering stuff like this. Thank you all!
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Graham,
I am new here but one thing I would caution you on: check your regulator. My new Hobart welder came with a regulator labeled for Ar/CO2 ONLY. I thankfully had a straight CO2 regulator from the other welder, but I was surprised that it wasn't capable of doing both for whatever reason. If you have an old one, then you are like me: ALL SET!
I am glad to see this info as I ran out of CO2 last night. I have a brand new bottle in the barn but was going to swap the empty and now have a decision to make as to what to get for my new spare.

Corey
 
cbrasher said:
Graham,
I am new here but one thing I would caution you on: check your regulator. My new Hobart welder came with a regulator labeled for Ar/CO2 ONLY. I thankfully had a straight CO2 regulator from the other welder, but I was surprised that it wasn't capable of doing both for whatever reason. If you have an old one, then you are like me: ALL SET!
I am glad to see this info as I ran out of CO2 last night. I have a brand new bottle in the barn but was going to swap the empty and now have a decision to make as to what to get for my new spare.

Corey
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More often than not, the flow meters that don't show Co2 are marked that way because they have less mass, and are more prone to freezing with 100% Co2. There isn't much difference in flow rate between Co2 and 75/25 when you look at dual scales, so that's not really a problem...you'd be off by a bit from what the gauge reads, but still close enough it shouldn't matter.

Co2 runs a bit hotter, but leaves more spatter compared to 75/25. For smaller machines or someone trying to really save money Co2 can be a good choice. My LWS is cheap...a 330 bottle swap of 75/25 only costs me like $65, and my machine has more power than I can imagine ever needing, so I stick to that rather than clean up spatter.
 
I always assumed that CO2 is used (in any amount) purely for cost reasons.
 
Yes, pure CO2 is only for cost reasons. All the others weld better. But, getting a paintball tank refilled.is pretty easy...

Sent from my SM-G892A using Tapatalk
 
Well, I continue to learn. Praxair says the reasons the costs are low is because CO2 is 800psi while the Ar/CO2 25% tank has to pass static pressure test @3700 PSI and is filled at 2200 PSI. So product exchange for CO2 to ArCO2 is $150 because the bottle cost is so much higher while the CO2 is $28 exchanged. Something new for me!
 
so does that mean that you get approx 3 x as many cubic ft of Ar/CO2 (2200psi) as you would pure CO2 (800psi) that would seem to mitigate the price difference somewhat
 
I believe CO2 is a liquid in the cylinder so you get plenty of volume without the increased pressure.

That’s why pure co2 is sold by weight not volume
 
kb58 said:
I always assumed that CO2 is used (in any amount) purely for cost reasons.
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I would not say that is completely accurate. Try short circuit MIG welding with 100% argon, and then with C25. Then cut-polish-etch the samples to see the differences.
 
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