Issues
Waterborne tinters, such as those for PPG’s ENVIROBASE® High Performance waterborne basecoat system, are typically stored in a temperature controlled cabinet to keep them in ideal conditions – between 20°C and 25°C. At cooler temperatures, high viscosity can be an issue – remember that solvent-borne coatings are significantly thinned (typically 50% thinner), whereas waterborne (
Envirobase High Performance) is only thinned between 12% and 20%. Also, when waterborne tinter get too cold it can crystallise which affects colour formulations.
Substrate temperature is another key concern because applying waterborne coatings has the effect of cooling the panel temperature by around 4°C to 5°C due to evaporation. Therefore, if panel temperature starts off too cool, drying times will be extended. In addition, all the usual rules need to be applied when working with the solvent-borne components, such as clearcoats and primers.
Tips and recommendation
- Regularly check the temperature in your waterborne tinter cabinet. Ensure that the thermostat is working correctly and that no one has knocked or messed with the setting.
- Store other products, such as primers and clearcoats, off the floor and away from concrete walls or anywhere else they can be affected by the cold.
- Place your mixed colour and clearcoat in the tinter cabinet to keep warm. Consider mixing products in SATA’s innovative RPS Cup System – it is plastic so it doesn’t respond to the cold like metal containers and it is quick, efficient and cost effective to use.
- Alternatively, put your mixed colour and clearcoat in the booth early to let it come up to a good spraying temperature.
- Consider some sort of mixing room heating if you are in a particularly cool region – it will make it comfortable for both the products and the technicians!
- Pre-warm panels to bring them up to a reasonable temperature which allows for the temperature drop when the waterborne coatings are applied. You can do this by placing them in the booth early and setting the temperature at around 27°C so they have time to warm up. In addition, if you have a gas-fired infrared system or a blower-type system, such as Lowbake’s Rapid Air Drying System (RADS), running a pass over the panels prior to application will also help warm them.