Has your car lost some of its shine? Would you like to get that showroom sparkle back? The problem may be swirls and oxidation of the paint. The good news is, if the damage isn’t too severe, it’s fixable.
You need knowledge of the paint job, car detailing products, willingness to work at it, and time. Before learning about removing swirls, scratches, and oxidation, it’s helpful to know something about the paint on your car.
Most cars built in the last 30 years received four layers of paint. First, the bare metal received an “E-coat” that resists corrosion. After the E-coat there is a layer of primer, followed by the color coat. The fourth and final layer is the clear coat. As the name implies, the clear coat is a transparent layer that lets the color show through.
The four layers of paint have a total thickness of 100 to 180 microns (µm). Typically the primer coat is around 30-35 microns (µm) thick followed by a 10-20 micron (µm) thick basecoat. The basecoat is the colored paint you see when looking at your car. A thick 30-100 µm clear coat is applied that forms a protective, glossy transparent coating.
Primer levels minor manufacturing defects and protects the car from corrosion, and provides a better surface for paint adhesion. The base coat contains the color and is usually referred to as the paint. The clear coat is a glossy and transparent coating that protects the base coat (paint) from the environment. It is durable enough to resist abrasion, some chemicals, pollution, and UV light; it slows down the rate of color fading by protecting the pigment from UV in sunlight. The clear coat also adds depth and gloss to the paint.
Many blemishes in your “paint job” are on the surface in the clear coat layer. Visual blemishes like scratches, scuffs, buffer marks, and swirl marks are typically confined to the clear coat layer. These imperfections in the clear coat are the ones that can be removed by polishing.
Paint Swirls and Their Causes
Look closely at paint that’s a few years old and you’ll see fine lines that “swirl” around. They’re more obvious on darker paint. Swirls are actually shallow scratches in the clear coat. You see them because they bend the light that strikes the car from an angle.
The main cause of swirls is car wash brushes. If you handwash your vehicle, grit in a wash mitt or drying leather can also create swirls. Providing these swirls haven’t cut into the color coat they can be removed. If you can see the primer under the color coat the damage is too great for the process we’ll describe here and the paint will need touching-up.
Recognizing Car Paint Oxidation
Oxygen atoms bond with almost everything they touch. When they bond with metal we call it rust, and when they bond with paint it’s oxidation. Oxidation starts out as a dulled appearance and if left unchecked, takes on a chalky look. Over time oxygen eats away the clear coat, exposing the colored paint underneath. Light to moderate oxidation is normally confined to the clear coat layer and can be removed with a polishing compound. If left untreated oxidation can eat into the paint layer. Heavy oxidation (recognizable by a chalky surface) needs to be treated with methods beyond the scope of this article.
So long as the clear coat still covers the colored paint, restoration is possible. So how is it done?
Removing Swirls and Oxidation
Restoring your car to that “as-new” shine entails lifting away a microscopically thin layer of the clear coat. That removes the swirls and oxidation and creates a good base for applying protective sealant. Here’s how to do it:
Start by gathering some basic detailing tools and materials. These are:
- Wash mitt
- Car shampoo
- Clay bar
- Polishing compound
- Microfiber cloths
First, handwash the car thoroughly to remove dirt and grime. Do this in shade and when the paint isn’t hot to the touch. Dry it thoroughly and then get out the clay bar.
When you buy a clay bar kit it comes with instructions, but in simple terms, you’re going to lubricate the clay and then slide it over the paintwork. This removes stuck-on contamination and lifts away any loose flakes of clear coat.
By now your car will look better than it has in a long time, but you’re not done yet. Now you need the polishing compound, (some call it cutting compound.) This compound is a very fine liquid abrasive that cuts away the thinnest imaginable layer of clear coat.
Make sure to read and follow the instructions. These will tell you to put a little compound on a microfiber cloth and gently rub over the paint. Circular rubbing motions work best. Work over an entire panel, then take a clean microfiber cloth and buff the surface clean and dry. You can use a power tool for cutting and buffing but unless you’re experienced it’s easy to overdo it. Cut through to the colored paint and the panel will need respraying!
Some detailers make cutting a multi-stage process with two grades of compound. If you have the time, it can produce amazing results, but again, be very careful not to overdo it.
One thing to remember with compound: don’t get it on plastic trim pieces. It can be very hard to get off.
Finally, once the whole car has been treated with compound, apply a quality sealant. In the past detailers used wax polish, but today modern sealants have taken over. These protect against UV, oxidation and anything that can cause swirls. They do wear off though and need reapplying after a few months.
New Life for Old Paint
Swirls and paint oxidation are inevitable but you don’t have to put up with them. Spending a little time following the correct procedures and can give your car that off the dealer showroom floor look. Follow what professional detailers do: freshen up the clear coat with a careful application of the polishing compound. A few dollars and a few hours of work will have your car looking like new!
Nigel Holmes started his automotive career at Rolls-Royce and progressed through various manufacturing and engineering positions before discovering a hidden talent for writing. Today, when he’s not writing about cars or tending to the antique Corvette in his garage, you’ll likely find him visiting a car show or museum.