What is a potential cause for gel coat crazing or cracking?

The correct choice highlights a significant issue associated with gel coat application: improper curing conditions. Gel coat that is too thick or over-catalyzed can lead to several adverse effects during the curing process. When too much catalyst is added, the exothermic reaction can generate excessive heat, which can result in thermal stresses that lead to crazing or cracking of the gel coat surface.

Additionally, when the gel coat is applied too thickly, it can also have trouble curing uniformly. The outer layers may cure faster due to exposure to ambient conditions, while the deeper layers remain uncured or are hindered in their curing process, which further exacerbates the risk of crazing as thermal and contraction stresses build up.

In contrast, other factors such as low gel coat thickness or insufficient application might cause different issues, but they are not directly associated with crazing in the same manner as improper thickness and over-catalyzation. Proper curing temperature is crucial to ensure that the gel coat sets correctly but does not directly contribute to the mechanical issues that lead to crazing. Therefore, understanding the balance of thickness and catalyst is essential to preventing gel coat failure.