Why did my Clear Coat turn out Matte instead of Glossy?

car painting

You want your car to look as sharp as possible, and not just for vanity’s sake.

In fact, the preservation of the car will determine how slowly or quickly it reduces its value (just in case you decide to resell).

It makes sense that you want to maintain its value since you’ve spent a lot of your hard-earned money to buy it; you don’t want it to look like it’s been hit by a monstrous tornado. It also helps to create a positive impression, for example when you pick up someone for a date.

However, most people are intimidated by the idea of having their paint job done, mainly because bad paint scares them off. The good news, however, is that the problem is easy to fix. It’s even worse when you delve deep into the paint job, only to find that the finished work looks like a matte finish rather than the shiny result you had in mind.

However, before you start correcting the error, you need to know a few things about the paint of your car.

What are the types of paint?

car paint

From the beginning of mass production of cars until the 1980s, car manufacturers applied a single coat of paint in a single operation. This left the car surface fragile, thin, and very susceptible to oxidation. However, things changed in the 1980s to the present day when they began to apply paint in a two-step system (applying a base coat, then a clear coat on top).

This made cars more durable, but they had one major disadvantage – they could easily deteriorate if they were not properly maintained.

Unless you have a car that is more than 40 years old, chances are your car has a two-point job.

Why does paint go bad?

spray paint car job

You know the feeling of getting a new car – so shiny and pleasing to the eye, and you want to drive around town excited about your shiny new tool. But you don’t realize that the sun’s rays are already beginning to destroy the beautiful paintwork.

The reason for this is UV radiation, which does more damage to your paintwork in less time than you know. When you think of parking your car in the blazing sun, the paint undergoes adverse chemical reactions. Combine this with pollutants in the environment and the paint starts to peel off.

Over time, if you fail to take care of the car, oxidation begins – that’s when you’ll start to see ugly spots on the surface.

By using a car cover and washing the car regularly, this is prevented and the cover also prevents dust from getting inside the engine; one of the main reasons why the internal components wear out prematurely.

What about the car paint turning matte?

Here there are two variants of the problem – the colour becomes matt after a few weeks or months, or it does so immediately after painting.

If the colour becomes matt after a few weeks or months, the possible causes could be one of the following:

  • The thickness of the clear coat is not sufficient: if you apply the paint in very thin layers of less than 50 microns or 2 mils, it will not give your car sufficient protection. In fact, car manufacturers will tell you that they cannot guarantee that the car is protected from UV rays if the clear coat is removed by more than 25%. The same rule applies to the refinish: if the spray clear is less than 41 microns, the protection is insufficient.
  • The quality of the clear coat is poor, as is the lack of UV absorbers in the chemical ingredients.

If the paint becomes matt immediately after application, this may be due to the following reasons:

  • The air supply line has moisture: this is one of the most common reasons. In fact, a water or moisture content of more than 3% is bad for the system. This is because water interferes with the chemical process that causes the paint on the vehicle surface to set, resulting in a matt finish. Water can multiply due to poor filtration and drainage in the air piping system and compressor overload, which increases the humidity.
  • The paint may have mixed with the hardener in the wrong ratio: the quality, quantity, and compatibility of the hardener ultimately determine the final result; so make sure the hardener is legitimate if you want a good paint finish. Hardener problems include using the wrong mixing ratio (use mixing and measuring cups when in doubt), the hardener is too old, the viscosities of hardener and clear coat are different, and the hardener is too fast.
  • There is some ambient humidity: when you have finished painting, the car must be kept in a dry room. If it is in a room with high humidity, the clearcoat will flake off due to the chemical reaction between the humidity and the hardener. In addition, the hardener must be sealed tightly immediately after us to prevent a reaction with the air humidity.
  • The flash-off time is too short: you must have sufficient time between the application of the base coat and the clear coat, especially if you use water-based paint.
  • You have applied a basecoat, but it is too thick: this causes the solvent to remain trapped in the film. To make sure the work is great afterward, you need to make sure that the basecoat is dry enough to prevent the solvent from being trapped inside.
  • Using the wrong reducing agent: this will lead to the thinning of all subsequent layers of paint.
  • The clear coat is too thick: this leads to much faster matting, especially if the drying temperature is higher than usual.

Final thoughts

These are some of the reasons why your car begins to matte after painting. Even if the solutions look like more trouble than they are worth, it is not as difficult as it seems.

Written by:

Magnus is the owner and main author of MechanicBase. He has been working as a mechanic for over 10 years, and the majority of them specialized in advanced diagnostics and troubleshooting. He has also been a motorsport (drifting) driver for over 5 years.