I have been using the HF 90 amp for about a year now. Definitely yes on the Lincoln wire. Do that and save some frustration. I am starting to weld some 1" Square tubing, and it does a great job. But on this metal you have to be fast, and have the heat cranked on high. Unfortunately the geniuses that made it only give you two settings. But I can lay down some decent welds with it, but it does most of the time require two passes. Works great with a 1/16" gap though.