Which of these factors is a common cause of 'orange peel' in spray paint?

The correct answer identifies high air pressure as a common cause of 'orange peel' in spray paint. When the air pressure is too high during the spray painting process, the atomization of the paint can become overly fine. This leads to uneven application as the paint droplets may not settle smoothly on the surface, resulting in a texture that resembles the surface of an orange peel.

In situations of high air pressure, the paint may dry too quickly before it has a chance to flow out and level off properly, exacerbating this undesirable texture. Optimizing the air pressure is crucial to ensure that the paint is atomized adequately and applied in such a manner that promotes a smooth finish. Proper atomization allows the paint to spread evenly, enhancing adhesion and finish quality.

Factors such as low spray pressure, outdated paint, and cold temperatures can lead to other types of defects, but they do not specifically cause the 'orange peel' effect in the way high air pressure does. Low air pressure may result in a heavier application of paint, potentially causing runs or sagging, while cold temperatures may affect the paint's curing process. Outdated paint might cause issues like poor adhesion or uneven color, but the physics of spray application is more directly impacted by the air pressure used