I have this old tsm tank that I wanted to modify with cutouts for a little more custom cafe look. This tank is rusty as Fuck. After cutting it open I discover quite a bit of pinholes coming through. I am hoping to line the tank after I am finished welding and block up all this pinholes. Anybody go through a similar process? What was the best method for sealing tank and getting rust out. Por-15 or some other stuff?