Car polishing is a widely misunderstood process, but it's very important for making the paint look as shiny as possible. In this article, we'll detail the features, risks, limitations, process and preparation needed to obtain the best finish for automotive polishes.
Auto polishing is the process of removing minor clear coat damage (scratches and swirl marks) using a polishing fluid to flatten the clear coat, thereby improving gloss. The polishing process can be done by machine or by hand, after which the paint should be protected with wax, sealant or paint.
Diamond Cut Detailing offers single- and multi-level paint enhancement and correction services. Lewis, owner and detailer are highly trained in machine polishing techniques to ensure the best possible finish in a safe manner.
polish is different from wax
This is probably one of the biggest misconceptions about car maintenance. Many car owners fall into the trap of using the words "wax" and "polish" interchangeably, when in reality they function quite differently.
Car polishes are slightly abrasive, which means they are able to flatten the clear coat (the top paint on a car). This removes any minor blemishes that are often caused by the use of sponges, brushes, or other aggressive techniques for cleaning paint during the cleaning process. The overall goal is to improve gloss. In short, the flatter the clear coat, the brighter the paint.
Waxes are not abrasive and will leave a protective layer on the paint to help protect it from UV rays, dirt, road grime, and more. Since they do not contain abrasives, they cannot flatten varnishes. Polishes don't protect the finish, so it's important to wax after polishing to protect the finish.
The confusion between waxes and polishes may stem from their basic claim that they both make paint look brighter. Waxes tend to contain chemicals that add a certain amount of gloss to the paint. However, their impact is not nearly as great as polishing. A truly glossy finish comes from the flatness of the clear coat, not what you put on top.
How does polishing work?
We've touched on this by saying that the polish is abrasive and helps flatten the clear coat, but that really needs more explanation. Clearcoats on cars are rarely completely flat and will contain some level of damage unless the car has been recently polished and well maintained.
Polishes contain mild abrasives in liquid form designed to remove damaged clear coat layers to reveal fresh, flat layers of paint. They can be applied using a machine polisher or by hand using foam or microfiber pads. They are applied in a circular motion, on a small area at a time, and used in paint jobs to remove an even layer. After polishing, the residue can be wiped off with a microfiber towel. Multiple attempts in the same area may be required to achieve the desired level of completion.
What types of scratches can polishing remove?
Polishing can only remove very fine clear coat scratches. It cannot remove scratches that have gone through the primer, which are usually white. Polishes are only intended to really improve the paint to a mirror finish.
To deal with deeper clear coat scratches, other techniques can be used instead. The most common, called compounding. Compounds are still used in the same way as polishes and in the form of liquids containing abrasives, but they have a higher level of "cutting" (wear) than polishes. This means they are more effective at removing clear coat damage. But keep in mind that they can't handle deeper scratches that penetrate the primer, as that would require adding paint.
Compounds sometimes leave some very slight "fogging" as they have a higher degree of wear. Polishing is usually done after lamination to improve the paint and remove fog to leave a glossier finish. This is called a two-stage paint correction, with the first stage mixing to remove clear coat scratches and the second stage polishing to perfect the finish.
There is another technique used to correct clear coat scratches called wet grinding. This is more aggressive than lamination and is used to deal with severe clearcoat damage. It leaves a haze that can be removed with a compound and then polished to reveal the shiniest finish.
Risk of polishing
Before polishing a car or using any of the above paint correction/enhancement techniques, it is important to understand the risks involved. Polishing is an irreversible process and once a clear coat has been removed, it cannot be recovered.
The clear coat is protective because it sits on top of the color coat, which protects it from UV rays, dirt, and grime, helping it retain its color. Removing a layer of varnish by polishing should only be done when necessary and with care to avoid removing too much varnish and compromising the integrity of the underlying color coat.
Since you cannot visually see the thickness of the clear coat, the safest way is to use a paint depth gauge. This allows you to get some information on how much clear coat can be safely removed. Once you know how much paint you're dealing with, the best way to do it is to use the least aggressive technique first, and then if you need to use more wear, you can intensify it.
Hand and Machine Polished
Before we get into the process, it's important to distinguish between machine polishing and hand polishing. Good results are possible with either technique; however, machine polishing will give a better finish by comparison. However, hand polishing is less risky as you are unlikely to remove as much clear coat. For a complete beginner, it's usually best to start with hand polishing as you get used to the technique.
Machine polishing requires more experience and skill. It is possible to machine polish a car yourself, however, most car owners don't have the expertise or confidence to bring a machine polisher to their car's paint.