Like he said, flux core,its abit messy but with practice its great for sheet metal.Keep in mind the rust spots are thinner and burn thru way faster. The lower door hing hole if the door is off. To put the door back in the same spot some folks will drill a few holes in the door and hing about the size of a small finishing nail so when they put it back they put nails or what ever in the holes an don't have to adjust it. I did the same on a 1972 mustake trunk, worked great.
