So this will be my first time ever trying to cut out panels and replace them with new ones. On the floor in my 1979 Chevy K10, it looks like a gun went off and put two holes in the floor. I don't see the need to replace the whole panel so I'm just going to cut out a little section and weld in a new peace. My question is after I weld in the new section, do I need to coat it with anything?