want advice on gas selection

On steel, I suggest C25 gas and ER70S-2 wire. Set up correctly, then you have your hot glue gun for steel, just what every boy needs.

GWE

I guessing your machine is a 110 volt unit??? C 25 is a good general choice. Keep in mind that the more carbon dioxide in the mix the hotter or more penetrative it is. The negative part is that you get more spatter as you increase the CO2. Those AWS articles have some good guidelines on gas choices. I am not sure how long it will be up before it is gone and next month's issue replaces it. You snooze.... You lose. Randy

One bottle of CO2 have a long duration and costs less than mix. Long duration because the gas inside is in the liquid state the problems begin in welding because you will have a more unstable arc and many spark (projections). A bottle of Ar+CO2 (mix) is relatively more expensive, less duration of CO2 but it allows you to execute better weldings aesthetically joined together and to weld thinner sheets. The welder is easier to regulate.

Thanks for the advice. I think I´ll go for a C25. BTW my machine is a 220 V (110 doesnt exist in europe) but its a small one (130A)

Henning

The reason I mention the size of machine is that smaller machines do not have the ability to adjust voltage up in the high twenties/low thirties. If one can then it is nice to use spray transfer but you need C20 or less to get the effect. Randy

Henning