No. A 100 amp MIG welder is NOT SUFFICIENT for most jobs! With only 100 amps I would advise against welding anything thicker than 1/16", and that would be pushing it! Otherwise you can expect your welds to have dangerous lack of fusion and lack of penetration issues. Also I would also only advise using a 0.030" wire diameter with such a machine.100 amps is disastrously underpowered for a MIG welder. Keep in mind that MIG welding uses about 19-30 volts, Whereas stick welding uses 50-80 volts. Therefore,...... in order to get the same amount of POWER and weld heat input, you need 2-3 times as much current with MIG compared to stick! Also the travel speed with MIG is significantly faster, thus you would expect to need more MIG weld heat than stick when welding materials of the same thickness. You want a MIG welder with at LEAST 300 amps or more, 400-500 amps is ideal. But if you want to make satisfactory welds on anything thicker than gauge materials you will need at least 300 amps. It's disturbing to me that many manufacturers of welding machines are under the impression that it's OK to sell such egregiously under-powered equipment. It seems their engineers and mangers do not understand even the most basic principles of electrical and welding engineering. Either that, or they simply do not care about the quality of welds made with their machines, They only care what will net them the greatest volume of sales. In my experience, Miller is notorious for not properly testing new equipment.