I see with my own eyes what increasing CO2 does practically, for the same settings... going from 5% mix to 18% mix will close up the arc length for the same voltage, and you have to increase the power source voltage substantially to get it to run the same arc length again. It also stiffens the weld puddle. So more weld energy goes into penetration and less wasted in a long arc, and easier puddle control.
What I've never been able to find out, properly, is why... I always thought it was something to do with arc voltage, and CO2 lowers it? Or raises it? Whichever it takes to close the arc length up... which I'd have thought would be lower, not higher?
@TechnicAl?
The higher the CO2 the less stable the arc becomes....voltage helps stabilise the arc
Penetration is controlled by Current (or WFS to be accurate) and the Stick Out length from the contact tip