The application quality of automotive refinish mainly depends on precise control of environmental conditions. As seasons change, fluctuations in temperature and humidity present varying challenges to the coating process.
Spring: Temperature getting warmer, High Humidity
As temperatures rise in spring, air humidity increases significantly. The biggest threat to the application at this stage is whitening of the paint surface, caused by moisture mixing into the undried paint film. The solution is to strictly control the dryness of the substrate and spray as soon as possible after cleaning to prevent moisture from re-adhering.
Summer: High Temperature, Accelerated Evaporation
In the height of summer, rising temperatures cause solvents to evaporate extremely quickly. High temperatures reduce paint viscosity, making it prone to sagging; simultaneously, rapid film formation, especially with excessively thick coats or insufficient flash drying time, which can easily cause the lower solvent layer to be sealed off, preventing it from evaporating properly. This problem often manifests as blistering or softening later during sanding or use. Therefore, summer application requires appropriately reducing spray viscosity, using slow-drying thinners to extend leveling time, and strictly controlling the thickness of each coat to ensure sufficient time for solvent to escape.
Autumn: Dry and Mild, Favorable Conditions
With balanced temperature and humidity, autumn is the ideal season for painting operations. Standard procedures can be followed during this time, but the impact of day-night temperature differences must still be considered. When painting in the early morning or late evening, it is important to verify that the substrate temperature is above the ambient dew point to prevent moisture condensation on the surface, which could compromise adhesion.
Winter: Low Temperatures, Slow Curing
Cold winter conditions pose comprehensive challenges to spray application. Paint viscosity increases, resulting in poor atomization; chemical reactions slow down, and curing time is significantly extended. Vehicles must be moved indoors for preheating to raise the substrate temperature to above 15°C. Fast dry thinners should be used to ensure fluidity; spray pressure can be appropriately increased to improve atomization. When possible, active heating with infrared lamps or similar equipment should be employed to accelerate the curing process and ensure the paint film achieves the required hardness and gloss.
In addition to seasonal adjustments, general principles apply year round: substrates must be thoroughly cleaned at all times; mixing ratios should strictly follow the product technical manual; and environmental temperature and humidity should be monitored before each application, with a thermo-hygrometer used as needed.
