A common alloy for steel bolts is called 316 stainless steel. Although 316 stainless steel is shiny, silver and will never rust, you might want to coat the heads of the bolts with paint to match them to their surroundings. For example, if you have bolts in your inner fenders or firewall, you might want to paint the bolt heads black so they blend in better. To paint stainless steel, you have to take a few additional steps to get the paint to adhere.
Clean the entire bolt head and surrounding area with mineral spirits and a clean, dry cotton rag to remove any oil or dirt. If possible, complete this process with the bolt installed. This will prevent you from damaging the paint with a wrench.
Place masking tape on the bolt head.
Apply acid etching to the surface of the bolt with the acid etching applicator. You can purchase acid etching at most computer supply locations. It is commonly used on computer boards. Allow time for the acid etching to dry. When dried, the bolt will have a rough texture to it. This is called abrading.
Paint the head of the bolt with epoxy paint and a small detail paint brush. Allow adequate time for drying before touching the bolt.
