If you are running Flux core wire Home Depot sells .030 wire, make sure you are running flux core wire on DCEN(electrode negative) the gun will be hooked up to the negative terminal. For solid wire it will be on DCEP (electrode positive). the gun will be hooked up to the positive terminal. Also what type of welder is it? If it is an inexpensive welder it could only be flux core or solid not both.