[bsmith123]

Well by the time I used the duraback I had already taken it down to metal, POR 15 metal prep, Aqua clean, then POR-15, then POR 15 top coat primer, then single stage polyurethane, then sanded the poly and applied the Durabakl

I suppose If I hadnt done all that I would at least use the acid and maybe cover the pitting with some zinc chromate primer then just DURABAK it per the instructions

OSPHO acid at ACE hardware will do the same as metal prep I put it on let it do its stuff then clean it off with a 3M paint and rust stripping wheel

my pitting was localized and not deep if it were bad enough to be a strength issue I'd of cut it out and welded in a patch

i am thinking a coat of epoxy primer would not be a bad thing either but I would check the Durabak instructions. I am pretty sure that stuff will stick to just about anything though but if you miss a little spot the primer would keep it protected especially in the corners and seams---Or POR 15 for that matter