Hi - first post have recently started welding as am restoring an old jaguar. Using a GYS smart mig all set up fine and have been practicing 1mm sheets using the thin metal method. This works fine on a welding bench and I’ve done quite a few decentish welds using this method however as soon as I do my first piece on the car itself using the same thickness sheet, I’m blowing through almost immediately on both pieces. I also seem to be struggling getting a decent earth - am clamped to a freshly ground to bear metal sill which is part of the workpiece but after a few mins work, there’s little power in the welds. Any advice really appreciated.