What is one possible cause of a paint coat applying too heavy?

One possible cause of a paint coat applying too heavy is low air pressure during the application process. When the air pressure is insufficient, the paint spray gun cannot atomize the paint properly, leading to larger droplets being produced rather than a fine mist. This results in a heavier application because the paint does not spread evenly over the surface. Instead of creating a smooth, even coat, the paint can accumulate in certain areas, leading to runs, sags, or an overall thicker layer than desired.

In contrast, using the correct reducer or thinner ensures the paint is adequately diluted for the desired application, while stroking too fast typically leads to a lighter application since the paint is not deposited consistently. Improper cleaning of the gun can lead to clogs, which might affect the spray pattern, but it would not directly cause the paint to apply too heavily. Hence, low air pressure is a key factor in preventing an overly thick application of paint.