Dealing with surface rust and aging seam sealant
My project is a 1965 Ford F-100 and my problem is surface rust in the bed and in areas where there is factory seam sealant. The surface rust in the bed has left the metal rough but the metal is not thin. To me, grinding the metal down is not the best way to go in that all I would be doing is thinning the metal. Maybe a little bit of grinding and then I should kill the rust or seal it in and then level the area with filler. If this is the best way to go what should I use to kill the rust and what filler should I use to level the surface? What should I do to the seam sealant at the metal joints in the bed and around the window drip edges? The sealant is coming up and I can see the surface rust. Do I need to kill this rust and reseal the joints?
When it comes to rust in a vintage vehicle you are always better off eliminating it altogether if that’s feasible. The only time I recommend using, and have myself used, rust “neutralizing” products is when it’s impossible or completely not feasible to totally eliminate all of the rust.
In your case, I suggest sand blasting the rust away. Remove all seam sealant from the seams to fully expose the underlying rust and blast these areas as well as the other rusty spots on the bed. Immediately after the blasting is completed, wash the bare steel with a metal prep solution designed for that purpose and then spray on a few coats of a corrosion inhibiting coating, such as a self-etching primer from DuPont or any of the other major manufacturers. If the pits in the sheet metal are very small you can use a sprayon, high-build primer to fill them. If they are beyond very small, use a high-quality lightweight body filler from Evercoat, DuPont, 3M, etc. to fill them in.