Which gas for the Mig 165?

[hyghlndr]

What gas or gas mix is best for welding steel? I have heard a mix of Argon/CO2 and another local person said straight Argon.

[heimbuckwelding]

straight CO2 is what i have used for years it gives you a good looking bead and the pennatration that you need especialy for that machine i have used it on miller matic 35 and a lincoln sp100 millermatic 175 tyhe 75/25 mix work well too but alot more splatter and cleqan up after words

[weldinglifer]

CO2 is cheaper. 75/25 will generally give you slightly better mechanical properties. Using the proper parameters both will do a fine job on short circuit transfer. If you are welding 1/8 and under, the 75/25 is less likey to cause burn thru. the straight CO2 will give you a bit deeper penetration. The HSLA steels used in modern automobile and light truck assemblies should be welded with 75/25. YOU DO NOT USE STRAIGHT ARGO FOR FERROUS GAS METAL ARC WELDING.

[hyghlndr]

Thanks, appreciate the help.