[A1Judge]

Use the POR on the inside of the fenders only, that is what I did, and I have welded in new metal to fix my fenders.

Although POR makes a TIE Coat Primer, that is supposed to let other paints stick to the POR, I did not want to risk it.

Completely clean all the rust, wire brush if you have to. Blasting would be best. Treat the metal with a Phosphoric solution, POR Metal Ready or Ras-O-Nil. That will stabilize any missed rust. Then do the welding. After welding, treat panels again, let dry then POR the inside,, USE a good grade of Epoxy Primer, (PPG DP40) on the outside. Then prime and paint as usual.

For filler work, to hide the seam,,, use the filler ON TOP of the epoxy primer, then seal the filler again with epoxy primer.. Then prime and paint as normal.

Hope that helps...

Don