This one is a Miller 220v with the timer module. Needless to say when using it on the roof skin, you let it rest on top of your shoulder to be able to stand the weight that long. We aligned the ends and tacked them, then checked the contour just above the drip rail with a body sweep and would adjust the panel's lower flange in or out accordingly. We made a few tacks to hold those locations, splitting it in about quarters, then went back and filled in between. About the only "cool down" was when we set the welder down to check fitment with the body sweep.