Lacquering offers an unlimited choice of colours with a very good colour conformity. Powder coating is the by far dominating lacquering method used today. Powder coating is done using a polyester powder with a layer thickness of about 60 microns, while wet lacquering gives a layer of about 25 microns. There are generally no limitations as regards the choice of colours. The RAL and NCS-S palettes offer a great number of colours.
The profiles are subjected to nine pre-treatment steps prior to lacquering:
- Alkaline cleaning
In order to obtain the right quality of the lacquered surface, it is important that the pre-treatment, lacquer application and curing are performed correctly. Since maximum adhesion and durability are desired, the pre-treatment has a decisive importance. It usually consists of degreasing and passivation of the surface, followed by chemical treatment (chromating). The pre-treatment is finished by rinsing the profiles in deionised water. The pre-treatment process is the same for both powder coating and wet lacquering. In all lacquering methods the quality requirements for pre-treatment are high.
The pre-treated profiles are covered with polyester powder. The polyester powder is adheres to the profiles as a result of electrostatic or friction charging, after which the powder coating is cured in an oven at 180ºC. Powder coats are applied and cured without any solvents. The ventilation air from the powder application process is cleaned in efficient purification plants. The powder that misses the profiles is collected in a recycling system and brought back to the spraying pistol.
Colour range for lacquering
Sapa works with all lacquer types that are in demand; apart from the traditional powder lacquer, this includes structural, metallic and clear lacquers. Polyester powder is used for powder coating and alkyd lacquer is usually used for wet lacquering. With lacquering there are practically no limitations as regards the choice of colours. We can offer all the colours that are included in the NCS-S and RAL palettes.