Ran out of CO2 today, so fitted a new bottle of Argon/CO2 mix. Without changing any other settings, it all went tits up!

The arc was forming well in front of the metal, and the wire was just foring a big molten ball that dropped down regularly, which virtualy no heat going into work. Sound was different, very quiet hiss instead of "frying bacon". Fiddled around and found I had to increase the wire speed significantly (about 30% more) to get it to weld properly, and then started to burn holes in everything, so had to turn down the current as well.

Finaly got it welding ok, and it is producing much nicer welds with virtual no spatter. However, is it normal to see such a big difference between CO2 and Argon?

Also I have found it even harder to weld upside down now, the nozzle keeps getting choked up with crap, what am I doing wrong?

CO2/Argon mix is better for mig welding. CO2 on its own is much much colder, so the settings would need to be changed

i noticed a similar thing when i started on argon mix. with more wire feed and higher current (i think i turned it up, but my machine doesnt have very precise current controls) i got it working ok. As the experts say, if you arent struggling with blowing holes, you dont have the current high enough!

nowadays i dont even think about settings (maybe a bad thing), when welding thinner stuff (16g) i have the current and feed down, on 3mm stuff i flick the power level and crank the wire feed up to 9.

Ah.. switches... hmmm dont have switches with TradeMIG, you have lots of knobs and i can safely say it makes a better weld. Especially now i'm using Argonshield (Argon/CO2)

I use lower amps with 5% argon than with neat CO2 but I only use CO2 if I run out of good stuff. If you're getting your shroud spattered up it's usually because your arc is too short but the hiss you described was the opposite. You might be better off turning your work over till you get the hang of it.