[catch2otwo]

I would use shielding gas, its much cleaner, less splatter, less clean up, less time. You'll be spending enough time trying to line up panels and prepping areas, why spend more time on unecessary cleanup. Get a mig 140 unit, able to use sheilding gas. Buy gas from the local welding supply rather than air gas. Air gas is much more expensive for my area anyway compared to the local shop.