In my OTHER spare time, I'm restoring a 69 Camaro which involves quite a bit more of the "restoration" of older parts.
Check out a product called POR-15 for restoration of rusted surfaces. If your surface is NOT rusty, or you just sandblasted it, check out ZERO RUST, it's easier to apply than por-15, but they are for different applications. (one is for a rusted surface, the other is applied on a non-rusted surface.) Also, follow por-15 directions to the T, the surface must be perfect. The zero rust is more forgiving and works well with minor preparation. (I recommend Zero Rust for your application)