This video shows a homemade compressor, generator and arc welder built from 8hp Briggs & Stratton Engine, Compressor and alternator which was found for no cost. I use the comp for rust proofing and connect it to a large air tank it pumps up fast. I have added a D10 alternator to the unit which can run power tools, lights etc. The alternator can also charge batteries and be hooked to an inverter. The pressure switch is off an old portable compressor it hooks to the electromagnetic clutch on the comp, the alternator is wired to self energize the field terminal attaches to the output main + I like to have a resistor in line to prevent the alt from over heating I can be bypassed for arc welding. The unit can weld fine with 1/16 inch rods in this video I tried 1/8 and was not able to make a good weld just blobs.