Without a little careful planning and preparation, a do-it-yourself painting project can go south in a hurry. Paint is nothing more than colored glue when you think about it. It needs to adhere to the surface or you'll have an ugly mess on your hands. Obviously, different materials offer different adhesion properties. Metal in general and chrome in particular present unique challenges that require specific solutions.

Prepare the surface

Start by cleaning with soap and water, but a proper surface cleaner--sometimes called wax and grease remover--is a must. Wipe it on the cleaned surface evenly, and then be sure to wipe it off while it's still wet. Always use a clean rag. Sanding before using the surface cleaner forces the contaminants into the surface--it doesn't take them away--so sand after the surface is clean. Start with 60-grit sandpaper and work up to a higher number to smooth out scratches. If there are dings or gouges that are too deep for sanding, wait until after the self-etching primer coat to use any filler.

Take your time

Self-etching primer is effective because it works its way into the top few molecules of the metal, and it is absolutely essential for the first coat. This bond needs direct contact to form, so any grease, wax or even fingerprints interfere with the process. Blow away all the sanding dust and do another sweep with the surface cleaner. Wait for any residual cleaner to evaporate before applying any primer or you will lock the compound into the surface. Don't touch the metal at this stage until it is covered with a coat of the self-etching primer.

Apply the top coat

When you've finished preparing the surface, begin with primer/filler as you always do. You might choose a high-build primer if there are still visible scratches from the sanding. Apply light, even coats. Follow the manufacturer's instructions for tackiness before applying a second coat. Allow the final coat to dry completely, then continue with several even, carefully applied color coats.

Source:

Painting Over Chrome

Painting Chrome Drum Components

Self Etching Primer: Discussion

Resource:

How to Use Surface Cleaner