The last vital layer of the skin is called topcoat. This finish has the purpose of providing a nice look, as well as the right gloss and feel. The topcoat is also of vital importance when it comes to the overall durability of the coating system, as it is the first protective layer that comes into contact with the elements. It requires great accuracy when applying it to the substrate.
To get a perfect skin, the application by spray needs to be done in the correct way. First of all, it is important to carry out the spraying in the right conditions. This means that the relative humidity should be between 50 and 60% for waterborne products during spray application. Furthermore, the ideal temperature for spraying is between 20 and 23°C. Please ensure that the temperature does not fall below 15°C.
Faultless spraying equipment
Once the surrounding conditions are right, you should make sure your spray equipment is too. The best results can be achieved with an air-mix pump. The ideal pressure for material is 100bar, for atomizing air 1bar (for cup spray gun please check details in Technical Datasheet). Please make sure the filter is clean and change it if necessary. Do not increase the pressure to more than 120bar to prevent micro foam on the surface. The right nozzle size for our products depends on your individual preference. Most of our products work with a nozzle size of 0.011 inches or 0.013 inches (0.23mm or 0.33mm). For more details please refer to the Technical Datasheet.
Vital last step – the drying process
After application, the next important issue is the drying of the topcoat. As always, it is important that the topcoat is given 20 minutes in a flash off zone with at least 60% humidity, 20°C and less air movement to give it the time needed for the foam, which is created by the high pressure of pumping, to disappear. Furthermore, the wet film also requires a certain time to level out nicely. Please avoid temperatures of less than 15°C as this will stop the film building process and can cause micro cracks.
After the time in the flash off zone, a higher temperature and lower humidity is advisable to speed up the drying process. Nevertheless, do not deviate from the drying time stated in the Technical Datasheet and make sure you have sufficient ventilation in the drying area. Even if the film feels dry, please keep in mind that it takes 4-5 days for waterborne systems until these are fully dried and film formation is completed. After this time the film is able to resist adverse weather conditions.