100% argon to MIG weld aluminum = Yes.

100% argon to TIG weld almost anything = Yes

100% argon to MIG weld steel = No

RTFM.

Also, check out the Lincoln website or the ESAB website for more info (theory, practical, etc) about welding.

www.lincolnelectric.com

Especially

http://www.lincolnelectric.com/asse.../assets/global/products/consumable_miggmawwires-superarc-superarcl-56/c4200.pdf

www.esabna.com

Especially

http://www.esabna.com/us/en/education/esab-university.cfm

and

http://www.esabna.com/EUWeb/MIG_handbook/592mig1_1.htm

 

100% argon mig is used for aluminum OR sheet metal body work. Won't really give you the penetration you're looking for, but yes you can do it.

 

Yes it can be done,

However pure Ar has some physical quirks that result in poor heat transfer from the arc. So it tends to not penetrate so well. It also tends to cause unstable, splattery arc operation with MIG.

You'll probably need to increase your voltage 1-2V when welding short-circuit with pure Ar.

The best all-purpose gas for short-circuit MIG welding is 75%Ar + 25%CO2. If you're welding really thin stuff sometimes it helps to use Ar +1% O2

 

In the pictures I've seen, it doesn't wet out very well with straight Argon.

 

He did say that the bottle is supposed to contain 90/10 mix even though the label doesn't say so. If true, he wouldn't be on straight argon. Granted, 75/25 is the best mix, but maybe he should use the 90/10 to practice, then when refilled with the proper mix, he will be a better informed welder when he sees the difference in weld behavior.

Just a thought,

Papa

 

co2 is active gas. It reacts with puddle. Argon is inert gas and it doesn't react with puddle. When welding steel and it's alloys (like stainless steel), you always need some co2 and i'ts reaction to get a proper weld. As mentioned before, the best gas mix for low carbon steel is about 75/25, 90/10 is used for spray transfer and 98/2 or similar are used for stainless steel.

 

If there is a chance its 90/10 then try it. If it welds then you are good to go. If not trade it to somebody with a tig for their empty bottle. No sense wasting a bottle of gas.