Miller Syncro 180

It is very good. I've been fabricating chassis out of 3/16 wall 2 and 3 inch square tube with mine. It hasn't overheated, but I sure have. :-)
It'll also go low enough to TIG sheetmetal, but modern auto sheetmetal is HSLA, and the manufacturers tell you to only weld it with MIG (ie because of the smaller HAZ created by MIG welding compared to TIG).
A Millermatic Pulser MIG would be the weapon of choice for most body shop work. If you're fabricating stainless headers, or need to TIG up fine decorative work, or need a superb stick welder, then the 180SD will fill the bill, but I'd choose the MIG for general body work.
Gary

I was under the impression that it went OA, SMAW, MIG, TIG(worst to best) for HAZ. Am I wrong?
JW

Yeah, you're wrong. TIG is similar to OA in technique and also in the HAZ generated. The main thing that controls the size of the HAZ is how quickly you can move along the weld seam. MIG is a *much* faster process than the others, so it produces the smallest HAZ.
Gary

Hmm. Ok. From what little TIG I have done so far, the rainbow pattern around my TIG welds are pretty small. I can see where MIG should have a fairly small HAZ. I haven't ran any MIG beads for awhile so haven't taken a good look at the HAZ lately.
Should it be OA-SMAW-TIG-MIG, or is TIG closer to OA than SMAW? It is all somewhat irrelevent as one needs to pick the appropriate process based on material anyways.
JW

i own a syncro 180 and have used it on sheet metal work, great machine (16 ga is the most used on panels) but i prefer my mig welder. i also own a millermatic 175 that is very adjustable for thin metal to thicker steel. tig is also very slow. if you're building a custom show car, nice tig beads are great, but if your replacing rotted floor boards and doing general repairs, i'd go with a mig. my 2 cents
walt

You do need to choose the appropriate process for the job. The HAZ for TIG will be a bit smaller than for OA in the same gage work because the heat is more concentrated, but otherwise their welding speed is similar, so the HAZ will be similar. MIG is a much faster process, so its HAZ will be smaller than either.
Stick isn't normally used for thin pieces. When welding thicker metal with any process, more heat is required. More heat equals larger HAZ. But thicker pieces also mean better heatsink, so smaller HAZ. What you wind up with depends on a number of factors, several not directly under your control.
But assuming all of the processes are doing the same weld on the same size and shape piece, with the appropriate parameters set for each to obtain equally sound welds, OA and TIG will have a larger HAZ than stick while MIG will still produce the smallest HAZ.
You can think of MIG as continuously fed stick (it isn't really that simple), if that's any help in this comparison of HAZ sizes.
Gary