Quote:
Originally Posted by STM
I priced it for 75/25 argon/co2, most common mig shield mix.
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If the blend has more than about 10 percent CO2 in it, it is impossible to get spray transfer with all but the very expensive pulse welders. This equates to slow and low current without much spatter, or faster and hotter with lots of sparks and spatter going everywhere. I use C25 gas, but it is on metal core and flux core welding (carbon steel) processes that create spatter anyway. It's also on a small welder that won't run fast and hot anyway. Sometimes I use straight CO2 with the same machine to get stuff done faster if I don't care how it looks. More CO2 usually equates to more weld porosity, which doesn't look pretty at all.
If you have a MIG machine that will do 150 or more amps, or may ever want to weld stainless or aluminum, get pure argon. Neither of these two metals like CO2 at all; using it in your shielding gas spells bad welds. Anything you want to look like it is expensive and stronger than it is should be welded with straight argon or helium, or a blend of the two.
An 80 CF bottle is pretty large for home use. It's also pretty bulky and cumbersome to move. If you don't do a lot of welding projects, it could take months or years to consume. They don't call it heavy industry for no reason.