An Overview of Motorcycle Chrome Plating

Close up, side view of a motorcycle's chrome engine and parts.
Ron Koeberer / Getty Images

When looking at a rusty pile of classic motorcycle parts, it is hard to imagine their former glory. But with hard work, most ​parts can be renovated.

With a few exceptions, all parts on a motorcycle have undergone some painting or plating process; the most well known of plating processes is, of course, chromium plating. The highly reflective bright finish of chrome has long been a favorite of manufacturers and owners alike. But what is chrome plating?

In a nutshell, chrome plating is a process whereby a thin layer of chromium is electronically transferred onto a component. The base material is typically steel, but brass, zinc, die-cast, magnesium, stainless steel, and ABS plastic can all be plated with nickel-chrome.

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The Importance of Preparation

As with painting or spraying a part, the preparation of the surface is very important when plating. The chrome plating will lie on top of any dings, scratches or blemishes; therefore, the component must be prepared/repaired and polished before being sent to the platers. (No point having a very shiny scratch!). However, most motorcycle parts plating companies offer a preparation service--for an additional fee.

The most common decorative plating on motorcycles is nickel-chrome, so called because the process involves nickel plating onto the component before a fine layer of chrome is deposited. The nickel plating is applied to the item to give a smooth, corrosion resistant base, and to supply most of the reflectivity. Occasionally, copper is also plated onto the component before the nickel.

When you examine a chrome plated item, the shiny finish is primarily the nickel that you are seeing. The chrome merely adds a bluish tint to the otherwise yellowish finish of the nickel.

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Ultrasonic Cleaning

The process of chrome plating starts with a polished component. The plating company will thoroughly clean the item to ensure there are no foreign materials such as fingerprints, oil, soap films, and buffing compounds on it. Some companies utilize an ultrasonic cleaning tank with special hot buffered cleaning chemicals to ensure cleanliness of the component to be chromed.

After the item has been thoroughly cleaned, it is rinsed in water then attached to a copper (for good electrical conductivity) hook. Further cleaning is necessary at this point by immersion into a dilute acid and water bath. Another clean water rinse follows before the item is finally ready for plating.

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Preventing Peeling

The first coating for many components is copper. The purpose of the copper is to prevent reaction with the base material of acids found in subsequent layers of nickel. The copper layer also ensures good adhesion, which helps to prevent peeling.

If no further polishing work is required, the item will be rinsed and transferred to the nickel solution where a heavy coat (or multiple coats) of bright nickel is applied. This coating forms the main decorative (shiny or bright) effect of the part.

After the nickel plating comes the chrome plating. The chrome layer is actually a hard, corrosion resistant, thin layer of translucent metal that acts as a barrier to prevent the nickel from tarnishing or becoming dull. More rinsing follows the chrome plating before the final phase which is to dip the part into hot solution to neutralize and seal the coating.

Although chromium plating is a durable long-lasting finish, time and use will damage its appearance. The good news is that the chromium can be electronically removed from most items (including mufflers). The chrome can be reclaimed by most specialist plating companies. Re-application of chromium will make the part look like new, which is something all restorers of classic bikes strive for.