What aspect is critical for preventing topcoat failures with primers?

The correct focus for preventing topcoat failures with primers lies in the primer's compatibility with the surface and conditions. Ensuring that the primer is suitable for the specific substrate and environmental conditions is essential for achieving proper adhesion and performance of the topcoat. If the primer does not bond well to the surface or is not formulated for the conditions it will face (such as humidity, temperature, or exposure to chemicals), this can lead to issues like peeling, blistering, or premature wear of the topcoat. The primer acts as a foundational layer, and compatibility is key to enabling effective sealing and protection, thereby ensuring the durability and aesthetic quality of the final finish.

While factors like the color of the primer, drying time, and thickness of the application play roles in the overall application process, they are secondary to the critical requirement that the primer must be compatible with both the surface and the environmental conditions in order to prevent failures in the topcoat.