Re: Body repairs
If you have a rust hole, a proper repair would be making sure there is no leak coming from the inside of the panel, grinding both sides and welding in a patch and finishing. If you have a leak on the inside of the panel, it must be fixed to have a chance at the repair lasting!
You could do a lesser repair of power brushing or grinding both sides, apply a rust converter like Ospho, bondo, and paint both sides. Cross your fingers...
Quickest way for a repair to fail is a leak from the back side. Water seeps into bondo and bubbles out the paint as well as allowing more rust. Paint both sides of of a hole repair!