Powder coating is clearly the painting method of choice today and offers an almost unlimited choice of colours from the RAL and NCS-S colour scales. Powder coating is carried out using polyester powder, to a layer thickness of around 60 microns.
Process stages in preparing for powder coating:
1. Alkaline wash
To ensure the desired quality of painted surface it is important that preparation, application and subsequent curing of the paint are done correctly. Preparation is critical to achieve maximum adhesion and durability. This usually consists of degreasing and pickling the surface, followed by a chemical treatment (chromating). The final stage of preparation is to wash the profiles in deionised water. All painting requires high standards of preparation.
The prepared profile is coated with polyester powder. The powder, which is applied to the profile by electrostatic or friction charging, is then cured in an oven at 180° C. The powder is applied and cured without any need for solvents. The ventilation air from the powder application process is filtered by an efficient filtration system. Powder that misses the profile is recycled and returned to the spray gun.