There is a black strip of metal between my driver's side window and the car door. The black strip of metal had been losing its paint such that you can see the silver metal underneath. Today I sprayed flat black paint onto the black strip of metal and the paint did not adhere to the black metal strip (you could still see the silver metal).



Given this, I had read that sometimes "sanding" with sand paper and then spraying the metal strip would help the black paint adhere to the metal strip. Is this true? If not, what should I do so that the black paint would adhere to the metal bar?

Are you sure it is metal and not plastic? Clean the area to be sprayed with mineral sprits. Use 400 grit wet or dry paper to lightly sand the material. Wipe with mineral spirits. IF you have sandable primer, apply a light coat, let dry for 20 minutes and lightly sand the primer. Wipe with mineral spirits and then spray the finish coat. If you do not have primer, sand, wipe and apply a couple of lights coats of finish material. Read the can about recoating. If not properly dried, the paint may blister with the second coat.

I was wondering: could I simply use a black permanent marker (like Marks-a-lot)?