He who paints in the sun will not get the professional results they are expecting. Paint whether oil or latex, thinned out or not dries or cures from air temperature, slower in the shade and faster in the sun.
The solvents or driers such as ASA (anti skinning agent), cobalt, naptha, mineral spirits, xylene, found in oil based paint evaporate at a much quicker rate when directly exposed to the sun. Whether spraying, brushing, or rolling paint sets up much like frying a egg in a pan when painting in direct sun light. This “setup time” will not allow the applicator to properly spread out or level the paint on the surface. The end result whether on wood, metal, or siding is going to be rough in appearance.
Before painting the exterior of any structure the painter must scope out the direction of the sun and its relation to the structure at different times of the day. He or she must work away from the sun!
This is most important when working on the roof painting, the sides of dormers, etc. The heat generated to roofing materials most notably shingles can reach temperatures well over 100 degrees.
Painting in these extremes is self defeating in that the paint sets up too quickly to properly apply it. In turn making the outcome of the paint job look unprofessional.
The painters tools react differently under different temperatures and don’t achieve the same results when painting in the hot sun. Brushes cake up, rollers dry out, and spray tips clog faster. The pot life of the paint curdles faster which is detrimental. To obtain the best results of exterior painting is to Paint in the Shade!