Chrome plating plays a role in giving old and out-of-print vehicles a motorcycle-like appearance.
Chrome plating is the best surface treatment to show off the metal’s massive appearance, but depending on care, rust can occur. This is where steel wool, a familiar kitchen utensil, comes in handy.
- Some decorative chrome plating rusts more easily than you might imagine.
- Rust on plating grows under the chrome layer and cannot be removed after it occurs
Some decorative chrome plating rusts more easily than you might imagine.
The rusting is different between the chrome-plated rims and the nichrome-plated spokes. The condition is more than adequate considering that the parts are more than 50 years old, but it is possible to keep them in good condition with less rust if they are kept indoors for a long time. Moisture and humidity are the enemies of both paint and plating.
Outdoor storage can allow rainwater and other substances to penetrate the gap between the rim and the tire, causing the underside of the rim to rust. Rust can eat into the rim band and tube, making them look as if they are glued together, or rust that has progressed from the backside can cause a hole in the rim itself.
Rust on the underside should be scrubbed off with a brass wire brush while spraying with an anti-rust lubricant. Painting with BAN-ZI’s Rust Killer Pro, which can be applied directly over the rust, is effective in preventing future rusting.
Chrome plating has a luster and a sense of massiveness that differs from paint and buffing, and is an attractive feature that gives the car an out-of-print or old-motorcycle look. Chrome plating uses degreasing solvents, chrome compounds, cyanide compounds, and other substances that lead to environmental pollution, so there is a worldwide trend toward reducing the use of chrome surface treatment. Chrome plating, which is harder than paint, more abrasion resistant, and has a unique luster, also serves as a rust-preventive treatment, of course. It is often thought that the rust-preventing capability of a base metal part with nickel plating and chrome plating to form a two-layer metal film (in some cases, copper plating is applied as the base layer to form a three-layer film) is very high, but this is not the case.
You may see old chrome-plated parts with pockmarks of red dot rust, but chrome plating has a weak point: it rusts more easily than you might imagine. The reason for this is micrometer-scale pinholes. The chrome-plated surface, which appears uniform to the naked eye, actually has numerous extremely small holes and cracks. Chrome itself does not corrode, but when moisture or humidity enters through these holes and reaches the bottom of the chrome layer, rust occurs. This rust grows and breaks through the chrome layer to the surface, forming point rust.
Chrome plating is a very thin layer of chrome plating over a relatively thick layer of nickel plating. The thickness of the plating varies, but as an example of decorative plating, the difference between nickel plating, which ranges from 5 to 50㎛, and chrome plating, which ranges from 0.1 to 0.5㎛, is overwhelming. Hard chrome plating on front fork inner tubes and brake caliper piston surfaces has a thicker chrome film (1-50㎛), which makes it difficult for moisture to pass through cracks and holes, resulting in less rusting than decorative chrome plating. However, as spot rust can also occur on inner tubes, it is inevitable that moisture will penetrate into the interior of holes if they are continuously exposed to moisture over a long period of time.
Rust on plating grows under the chrome layer and cannot be removed after it occurs
Rust on the rim surface is caused by moisture that has penetrated through microscopic holes or cracks that exist on the chrome-plated surface. Therefore, by the time spot, rusting is observed on the plated surface, the plating film in that area has been broken and cannot be completely restored to its original state. It is important to take care of the plating before this happens, but it is possible to improve the situation even from this point on.
If the machined finish of a cast aluminum wheel becomes white and corroded, it can be recovered by polishing it with an aluminum polishing compound or chemicals. However, rust on chrome plating cannot be removed by polishing because it originates from beneath the chrome layer, just as a plant seed buried in the ground grows and emerges on the surface, as mentioned earlier. This is similar to rust progressing under the paint and causing the paint film to lift, and the only way to completely restore it is to strip the plating and redo it from the ground up. In this case, a plating specialist will remove the chrome and nickel plating to expose the surface of the metal material to remove the rust, and then nickel and chrome plating will be applied again. Just as there is a reasonable cost for a paint store to re-paint, there is a cost for re-plating as well. As mentioned at the beginning of this article, the chrome plating market itself is shrinking, and there are fewer and fewer companies that perform re-plating.