I`ve run as big as .045 in my ya212 , but it came with some.100 tips. So apparently the guy I got it from was doing some serious welding with it. Before his divorce , He had a body shop and built e-mod and sprint car frames, I`m pretty sure this is the welder he used. I only use .023 wire for sheet metal it takes less heat,so there`s less chance off warping and burn through.