Quote: When using this method on old metal that has rusty pit marks on it, what can be used to try to fill these pitted areas? Maybe some type of primer or a finishing putty or some type? Maybe regular filler? Thanks.
Just use regular filler but before you add the hardener, add a bit of fiberglass resin to the mix to thin the bondo a bit. Mix it in. Then add hardener, mix and apply. Thinning it like that will reduce pinholes and make it easy to apply to such small areas with these tiny imperfections. Rough with 80 then go to 180 to smooth out..
