The Stovebolt Site Forums The Shop Area Paint and Body Shop Rust removal

I am cleaning up some parts of my 47 preparing for new paint. I am stripping the rust the best I can to bare metal. Here is my concern and question. Some parts are not just flat continues pieces that can easily be stripped. I am worried about the ones that have an another piece welded on or an overlap. The connection of two different pieces. What if there is rust in between those two pieces? How do I make sure it does not creep out under my new paint? Do the rust inhibitors in some of the primers work and kill that hiding rust? Should I give these areas a shot of rust restorer (the stuff that says it converts rust)? Is there some other treatment I should do before priming? Example is my bumper and a welded on license plate bracket.

Most "rust converters" contain some sort of acid (phosphoric?) that attacks the chemical makeup of the rust (iron oxide) and turns it into something that theoretically doesn't continue to deteriorate the metal. Sometimes the cure is worse than the disease, when the acid that's trapped in crevices leaks out and lifts primer or paint. I'd suggest using a high pressure washer to blow any residue out after using any kind of chemical to kill the rust.
Jerry

For any multi-layer part that has significant rust and scale between, you will normally see the tell-tale signs of swelling between the two parts, especially noted in the middle between spot welds. Yours still looks flat, so anything between is minimal at best. I'd media blast in the crevices for a good abrading for paint to stick, followed by a quality epoxy primer. But prior to spraying, use a brush with your epoxy primer and attempt to brush and "wick" the paint between the panels in an attempt to fill any void. Wipe off any excess and spray away.

If you do see any signs of significant rust, you could always remove the part by drilling out spot welds, clean all parts/fabricate new as needed and reassemble using plug welds.

The main reason why I have my cabs and body parts media blasted is for those places which you mention. Once you blast those seams where the sheet metal joins or overlaps, there will be no rust or paint left on the outside. I then use SPI epoxy primer. This product will seal those areas, preventing the rust from creeping out later.
One important note. Do not treat these areas with rust preventers like Ospho if you are going to use epoxy primer.. Epoxy primer does not get along well with acid rust converter products.