Rust Treatment

[bigsky]

Front fenders, behind tire well has some surface rust. I have sanded metal bare, leaving the surface rust pits. I got this treatment from the local Napa store. Can I use this treat, then Bondo/primer over the top of it???

Is there a better way/product to treat these surface pits, short of patch panels?

[Ironangel]

I use Phosphoric Acid to treat and reform rust. It's the active ingredient in Navel Jelly and most other "rust reformers". I use a garden type (pump) sprayer to spray the rusted areas and allow it to dry. Remove as much loose and flaked rust as possible with a wire wheel or brush and spray the acid solution on dry clean rust and allow it to dry completely. The rust (Iron Oxide) will turn into a hard black compound (Iron Phosphate) that can sanded (best left undisturbed) and primed and painted. I spray rusted headers and then prime and paint them with VHT "Flame Proof" with excellent result. I sprayed the bed on my 72 C-10 3 years ago and followed up with a roll on cold galv and then roll on bed liner and no more rust to this day. Home Depot has it, may even be whats in that Permatex can? Phosphoric acid changes rust and prevents it from reoccurring, other acids only remove rust but wont prevent reoccurring rust. http://www.kleanstrip.com/product/phosphoric-prep-etch