Ensure a successful summer paint job. Be mindful of the air, substrate and paint temperatures. Most exterior paint is formulated to perform best when applied at temperatures between 50°F and 80° F. As the days become increasingly hotter through summer, the application and proper curing of latex and oil/alkyd paint can be negatively affected by excessive air and substrate temperatures.
Air Temperature - The proper formation of the paint film can be seriously affected if paint is applied when air temperature is above 80° F. Pinholing can occur during application and direct sun on fresh paint can cause the film to blister. Dry spray is a common problem, particularly with airless spray application when temperatures exceed 80°F.
Substrate Temperature - When the surface temperature of the substrate is above 80° F, it can significantly affect the dry and cure process and prevent proper film formation of the paint. Lap marks may result when the coating is applied to a hot surface. It is important to note that the surface temperature can vary between different areas on the same structure causing the dry time and proper film formation to vary as well. Follow the sun around the structure when painting to avoid subsequent heating of the surface before the finish has dried.
Paint Temperature- The viscosity of the paint is also affected by temperature. Store the paint in an area that will not exceed 70° F. Paint that is applied when it is too hot will not flow and level properly and can affect proper film build. If the paint is left to sit in direct sunlight a skin may form inside the bucket.
