I've been wanting to teach myself to mig weld so I bought a Miller 210 and have been practicing. The chart inside the 210 is helpful with the voltage and feed settings but I'm not yet clear on gas pressure. Is there a basic rule of thumb, such as material thickness vs. psi? Or is it one setting for most materials? I'm using 25 CO/75 Argon.
the gas flow is measured by volume, not pressure. 15-20 cfh would be ok to cover anything indoors for the capacity of your welder.
one thing for newbies is they hold the torch too tight, relax your shoulders and hold the gun with BOTH hands. assume you're right handed, use your left hand as a guide and shield. weld from left to right(drag or pull). don't do right to left(push)
3 thinks matters once you pull that trigger:
stick-out, torch angle and torch speed.
keep the "stick out" constant, no more than 3/8". that's the #1 problem I see when people having trouble with.
keep the torch angle between 15-20*
speed, whatever you can keep the width of the bead 1.5-2 times of the thickness of your material.
remember, when you start a bead, that work piece is cold, you need more heat(slower speed) for the bead to build up, once it's started, the work piece is getting hotter, you need to speed up to compensate.
look at ZT's work, notice the bluing line (which indicates the heat) is extremely consistent. you don't get that from "tack, tack, tack".
don't try the fancy movement, yet. "stop 'n go" is all you need to do.
one last thing, breath through your nose, pull the trigger on exhale.