I have a 110 Mig-100 Harbor freight welder. Non-gas. I have it on min power and a decend speed. I am getting blow thru first off. And next I changed from the supplied .8 mm flux core (silver) wire. I changed to .8mm (brass colored) wire and the weld sits on top of the metal and spatters all over. What is the difference in color? How do I fix the blow thru headaches??? I am welding auto sheet metal (trunk and fender sized, 20 or 22 gauge, I think)?????