Ken's correct. I'll add that there are "dual shield" wires, that have a flux-core AND require gas. Some are straight polarity, some reverse, so it's best to check the maker's recommendations for these. I doubt you'll find one for a smaller machine, though. I've never seen a "dual shi...

Reverse polarity or Electrode Positive is used for solid wire MIG (GMAW) welding with shielding gas. Straight polarity or Electrode Negative is used for self shielding flux core (FCAW). You would need to change the polarity when you change the wire type. Ken Okay Ken, If I understand you correctly,...

On my Hobart Handler 120 I have a reverse polarity option. I have never used this. When is it necessary to do this ?

Thank you very much for the response, Steve S. and Otto N. Excellent suggestion.I will do that.

I have a Hobart Handler 120. I only have 4 heat ranges 1=18-24ga. 2=18ga. 3=11ga. And 4=max Wire speed is 1-10. How do I deal with voltage settings that call specifically for a certain voltage when I don't show it? I've had this welder for a while. Did I screw up buying this welder?