The variety of materials and substances used to produce all kinds of vehicles is dizzying. The desire to stand out from the crowd of similar cars forces manufacturers to use several types of materials on one vehicle. However, in the end, the whole thing must have the same color - regardless of the materials used. This is where paint manufacturers come into play - trying to combine water and fire, i.e. maintaining high paint adhesion regardless of the substrate while maintaining a uniform body color. .

Every professional notices the appearance of new products on the renovation paint market, which are tempting mainly due to their low price. Problems arise after the paint has been applied, when the freshly applied coating comes off the painted element or the resulting color leaves much to be desired. Of course, painting is a complex process and the end result is the sum of many parts. Unfortunately, even the best prepared surface and high-quality painting equipment will never replace good quality paint, and sometimes good paint will even make up for shortcomings in other elements. Let's remember that the final result of the painter's work is not only a perfect-looking coating but also corrosion protection for our car for many years.

Are you interested in what a car in a selected color looks like? See the entire RAL color palette

The cause of enormous financial damage among professionals convinced of the right paint purchase is not only poor surface preparation but also to a large extent the use of improperly prepared paints by companies that do not devote enough time to thoroughly testing their products before releasing them to the market.

Returning to the durability of paint, one of the most important parameters responsible for this, namely adhesion, should be described. Good adhesion to the substrate is caused by the occurrence of adhesion (Latin: adhaesio - sticking). It is a state in which two surfaces join together. The paint used for protective or decorative painting of car parts can lie on their surface or penetrate slightly into the surface. If we look under a microscope at a high magnification, we will see that the paint consists of particles, most often in the form of pigments and additional substances.

In order to be effective, paint coatings should have good adhesion to many types of substrates. Both adhesion and cohesion are required in painted components for long-lasting coatings. The adhesion mechanism can be summarized as follows: after being applied to the surface, the paint particles form bonds with the substrate. Chemical bonds are then formed on the joined surfaces. In the final stage, the paint penetrates the unevenness of the surface and is then mechanically locked after drying. Therefore, it is important to use a primer that provides adhesion for the topcoat (see figure).

The painted surface is not really smooth, and can be compared to a terrain full of valleys and hills. According to the theory of mechanical adhesion, a properly functioning paint coating should penetrate the unevenness of the surface, displacing the trapped air in the cracks. The paint should wet well and thus penetrate the surface to be painted. This increases the adhesive strength and thus the coating adheres to the painted object. Adhesion is divided into mechanical and chemical adhesion. The actual adhesion is caused by the molecular bonds between the paint components and the surface. The mechanical adhesion, on the other hand, is the main factor for the paint to adhere (approx. 75%) and is caused by the liquid paint penetrating the pores and unevenness of the surface.

A painted surface is not really smooth, but can be compared to a terrain full of valleys and hills. According to the mechanical adhesion theory, a well-functioning paint coating should penetrate the unevenness of the surface, displacing the air trapped in the cracks. The paint should wet well and thus penetrate the surface to be painted. This increases the adhesive strength and thus the coating adheres to the painted object. Adhesion is divided into mechanical and chemical adhesion. The actual adhesion is caused by the intermolecular bonds between the paint components and the surface. The mechanical adhesion, on the other hand, is the main factor for the paint to adhere (approx. 75%) and is caused by the liquid paint penetrating into the pores and unevenness of the surface.

Too little adhesion can result in a reduction of the actual contact surface with the substrate, numerous stresses and the formation of air bubbles. These are sufficient reasons why the final result of the painting can be deplorable. Therefore, a series of tests should precede the sale of the product. One such test is the cross-cut adhesion test according to ISO 2409, ASTM D3359. This test determines the resistance of the coating or paint to separation from the substrate when rectangular cuts are made in the coating down to the substrate. Another problem besides the lack of adhesion is that the color on the painted element is different than expected. If we ignore errors resulting from gaps in formulation programs, the cause of this phenomenon is the incorrect positioning of the pigment during the drying process. This phenomenon is particularly noticeable in car colors containing metallic pigments. Many factors influence this. The first is the use of poorly selected raw materials in the production process, which are designed to distribute the pigment evenly after the color has been applied to the part. By using the right additives during drying, the pigment is evenly deposited on the surface.

Metallic pigments have a different structure to solid pigments because they resemble the structure of flakes when greatly enlarged and are much heavier. Therefore, it is important to mix the base thoroughly before use. For example, Kar-Bon paint colorants from Profix should be mixed once a day for about 15 minutes.

Poorly distributed pigment causes an unnatural pigment orientation, and the color seen is far from what is expected. The best arrangement of the flake pigment is uniform, and this is when we get the most satisfying result. Much worse effects are obtained when the pigment is grouped or unevenly arranged (see figure).

Another factor that can cause an unexpected color is the use of the wrong thinner. Often, in order to save money, cheaper substitutes are used, thus risking a change in the shade of the painted coating. Paint manufacturers produce suitable thinners which are selected based on various tests. Choosing a cheaper thinner often means that it evaporates faster. We are not able to see this in the first stage of painting, but the problem becomes apparent after drying. We can then notice the so-called “roughening” - where the structure of the painted surface is not smooth but rough. This is caused by the faster evaporation of the wrong thinner.

Try to use products and technology from one manufacturer, then you can be sure that by following the guidelines you have a manufacturer's guarantee for the coating obtained. Multichem is so confident of the quality of its products that it offers all customers a 10-year warranty on the coating. All you have to do is use PROFIX brand products and technologies. The warranty also covers the new Kar-Bon color selection system.