Wet coating can be roughly divided into spray coating and dip coating.
Due to the inexpensive equipment and since it allows a wide spectrum of paints, spray coating is the most widely used method of surface protection. It is suitable for industrial mass production or one-off manufacture in small-size plants.
Dip coating is a very high-yield process. It is frequently used for work pieces with many hard-to-reach places, which would make the spray coating process take too long. The prerequisite for dip coating is, of course, that the work-pieces can be immersed, so they do not include surfaces which cannot come into contact with coatings.
Powder coating is appropriate for protection of all types of metal products. It ensures excellent surface protection, as well as an aesthetic appearance of the product.
Besides excellent surface protection and a wide range of colours, textures and colour effects, it is also distinguished by its high yield (up to 98 %). Appropriate technology enables the powder that does not adhere to the work piece to be almost entirely recovered and reused. One of the advantages of the powder coating is also its environmental sensibility. Powder coatings do not contain highly volatile matters which could be released into the environment during the coating process.
Electrophoretic coating is appropriate for protection of all types of metal workpieces. In practice, we distinguish between cataphoretic and anaphoretic application of coating.
The cataphoretic application of coating is a process that involves passing of a direct current, in which the workpiece is connected as the cathode (negative charge) and the positive particles of the cataphoretic coating are deposited on to the metal part with a help of the anode cells. In the case of the anaphoretic application, the two poles are changed, the workpiece being an anode (positive charge) and the cells work as cathodes. The fundamental principle in both processes is that materials with opposite charges attract. The thickness of the coating layer is determined with a help of voltage, which enables formation of an even continuous film on each of the workpieces. The electrophoretic coating deposits on to the workpiece until the latter is completely covered with the desired thickness of an even continuous film.
Electrophoretic coating ensures the best surface protection among all coatings, as well as an aesthetic appearance of the work pieces at very low costs. It is also an environmentally-friendly process as the electrophoretic coatings do not contain highly volatile matters. All these are the reasons for it to be favoured in the automotive industry.