Chrome plating gives rims their characteristic bluish tint and protects the copper and nickel undercoat.
The thickness of chrome plating on aluminum rims, also known as decorative chrome plating, is extremely thin, measured in millionths of an inch. This shallow plating is what provides the shininess, smoothness and resistance to corrosion many car and motorcycle enthusiasts value for their rims. Chrome plating is a combination of several processes, involving copper, nickel and chrome plating. It is the copper and nickel plating that provide chrome rims their smoothness, brilliance, resistance to corrosion and reflectivity. The chrome plating protects the nickel undercoat and gives the rims their characteristic bluish tint.
1. Clean your aluminum rims with an aluminum polish and a vapor degreaser to eliminate all impurities before you start plating.
2. Immerse the aluminum rims in a bowl of sodium hydroxide. This will corrode the surface of the aluminum rims to prime them for plating.
3. Immerse the corroded aluminum in a bowl of etching solution to further roughen the aluminum. Rinse your rims with water.
4. Place the aluminum rims in a bath of charged sulfuric acid. This treatment is called electrolysis. The bath has charging plates attached to a battery, causing the sulfuric acid to fall out of solution and react with the aluminum.
5. Dip your rims in a bowl of liquid copper. Dip your rims in a bowl of liquid nickel and rinse again with water.
6. Dip your nickel-plated aluminum rims in a bowl of charged chromium anhydride, a solution of liquid chrome and an electrolytic salt. The charging plates in the bath will cause the chromium metal to fall out of solution and attach itself to the nickel plating.
7. Remove the rims from the charged chrome bath and rinse with water.