Transparent but visible topcoat

It may sound contradictory, but clear coat has a big impact on how we perceive the color of a car. Clear coat is mainly associated with the protective layer of a vehicle, a kind of glass in the window - thanks to which we can see everything and at the same time we have a protective barrier. Contrary to popular belief, clear coat has several functions at the same time. I will try to briefly discuss them.

The most important, especially over the years, is the protective function of the paint against weather conditions. It is no coincidence that the color of the car changes so slightly over time, because it is from this angle that good clearcoats are designed and tested.

A test only for the best.

Testing clear coats is a very interesting topic. I can reveal that Profix products undergo one of the most difficult tests in the world, the so-called “”Florida Test". For more than 75 years, the Miami area in Florida has been the benchmark for outdoor weathering tests. One year of testing in Miami equals several years in other locations. Florida has very intense sunlight, UV radiation, high annual temperatures, heavy rainfall and very high humidity. The coating is subjected to a great deal of stress due to the presence of salt water spray in the air combined with very high levels of solar radiation, especially UV radiation.

We have our own laboratory there where we carry out these tests. However, this is a topic for a separate article.

Weather conditions are only one side of the coin; the other is equally important mechanical resistance (e.g. to scratches). Every person looking for a free parking space knows how easy it is to have an “adventure” with scratching the door when getting in or out of the car. It is precisely the hard colorless surface that often protects our cars from being damaged by scratches. When it comes to use, an important, though sometimes ignored, factor is keeping the car body clean. It extends the life of the coating - even by several years. Nothing damages the clear coat as much as bird droppings. The chemical reaction they cause destroys the paint surface.

Pleasing to the eye.

We already know that a good product should fulfill several functions, including protecting against weather conditions and preserving the color of our car. Now for the more aesthetically pleasing part – the appearance of the coating. Clear coat can give our vehicle's color more clarity and depth, increase gloss (if desired), or maintain a matte appearance. A matte appearance has been a long-lasting trend in the paint market. A matt coating gives the car body a unique character, but it is a real challenge for paint manufacturers. In short, I can say that the paint requires the use of demanding production technology to maintain the same protective qualities as gloss paint.

The question remains, do we always have to apply clear coat?

Of course not. Most solid colors can be achieved using 2K acrylic paints. When painting the surface with acrylic paints, e.g. CP 88 Premium, there is no need to use clear coats, and the resulting coating has full protective properties and looks like it was painted with a clear coat.

When it comes to renovation painting, we often have to paint the engine compartment – and here, in order to shorten the whole process and maintain a uniform color, we can use additives in the form of special resins (e.g. B-03 Kar-Bon), which, when added to the base paint, do not require us to apply a clear coat. However, if we choose clear varnish as the finishing coat, we are left with only the varnishing process. In most cases, we apply clear varnishes using the “wet on wet” method, i.e. on a clean, unsanded surface of the 1K base coat (which can be wiped with an antistatic cloth). After applying the last layer of base coat, we have to wait about 10 minutes. This is the time needed for the coating to evaporate and then we apply the clear coat. The number of layers depends on the varnish used. Finally, we just wait for the varnish to dry. Most clear coats need several hours (without using a spray booth) or several tens of minutes in a booth to dry completely. Recently, however, progress has been made in this area as well, and you can now get a coat that dries in 5 minutes (CP 2015 HS X-SPEED).

Yes, you read that right: 5 minutes is enough!

When painting with clear varnish, there are a few things to keep in mind to avoid costly mistakes. First of all, try to get a set of materials from one manufacturer - even the best clearcoat combined with a poor-quality hardener or thinner will result in a poor coating and you will have to repaint.

It is worth reading TDSs.

Common mistakes that I notice in my work include too short or too long evaporation time of the base coat. In the first case, if the time is too short (usually less than 10 minutes), we may have problems with obtaining the right color of the coating or poor adhesion to the substrate. With a long evaporation time (over 8 hours), the so-called flaking of the coating may occur. Another pitfall for the painter is an excessively thick layer of clear varnish, which causes outgassing. I will come back to additives (hardeners and thinners) later. If we choose the wrong proportions or variants (fast hardeners, slow hardeners, etc.), we will end up with orange peel or water spots. The range of paint defects is really wide and describing them would fill a whole book. These are just a few of the most important warnings and tips.

In addition to what we paint with, where and with what equipment we paint is equally important. Ambient temperature and humidity are very important, as are the size of the nozzle used and the pressure in the spray gun. So let's read the technical data sheets that come with the product and follow the recommendations they contain.