Although polishing chrome is often considered to be the same as polishing metal, there is a slight difference. Because chrome has more of a mirror shine, imperfections are much easier to see with the naked eye. Making it more difficult to achieve a perfect result.
Difference between metal and chrome
Most metal parts don’t have the flawless mirror shine that chrome offers, this is one of the reasons that chrome is popular when adding the final touches to a show car, or when designed a vehicle. Chrome adds shine, class and can create a stunning reflective effect. This is less easy with other types of metal, although it is not impossible. Most chrome used on cars is so called “chrome-plated”, meaning there is only a thin layer chrome on top of something else. This can either be another type of metal, or plastic. The thin layer of chrome is very thin, and can easily be damaged. Chrome itself does not rust, so when seeing rust on a very fine polished surface, it is likely due to it either being another type of metal or the material underneath the chrome has started to rust.
How to get the perfect result
Just like when polishing paint, you need to remove the deepest imperfection before you can start to finish the final result. Using a more rough metal polish will likely take care of the deepest imperfections. Using a machine will help. Start by removing the deepest imperfection, wipe down properly after polishing, then go down 1 step and work your way down to a finishing polish. Using dedicated metal/chrome polishes will likely result in a better finish. When done, make sure you wipe down properly and inspect under different angles of light and different types of light.
Important things to look out for
Chrome is different then a solid block of 1 material. If you take a wheel made from a solid piece of aluminium, it won’t matter how deep you cut. You will always see aluminium. With chrome-plated materials, you only have a very thin layer of chrome to work with. Measuring this thickness can be difficult because the cheaper paint thickness gauges won’t be able to tell the different between chrome and metal, or they will simply think the chrome is the only metal they need to find. Even when the thickness is 200 micron, it will still read 0 micron on the display. The gauges that are capable of telling the difference are very expensive.
Another problem with chrome is its inherently flawless surface. Chrome is popular because it naturally has a perfect and flawless mirror-like surface. When it has imperfections, these will stand out. A result from this is that you will be more likely to find imperfections after you are done polishing, something that is more easily hidden on a painted surface. Due to the required level of cutting to achieve proper results, and the level of perfection you want to achieve, it can be a very difficult task to get a flawless result under all angles of light.