The stud welder *****. My Snap On stud welder was stolen about 6 months ago, and I replaced it with the HF welder... mistake. The first time using it, it rocked, and I regretted buying the Snap On kit. But.... Next session (same day), it wouldn't penetrate the metal, and the studs kept pulling off with pulls (and I don't mean heavy rocker damage, I mean a light crease! Or, they pop off with little pressure and hammering on the highs around it!) , or not even welding at all. I'm no novice to metalwork, bodywork and welding, so I know how to use the ferking things... It has no balls, cannot weld studs properly, the duty cycle ***** (get on a roll welding studs beaten panel, and it trips the breaker fast - really puts the breaks on a session).
I still have it, and every couple of days I give it another try when working, and it just plain ***** ***. Until I can afford another Snap On unit, I just tack the studs to the panel.
I assume that if you're looking for a stud welder, then you have the skill to use one and work metal. You will be unsatisfied with the HF unit, save up and buy brand name.
Just my opinion.