What is the purpose of a guide coat?

The purpose of a guide coat is to serve as a visual aid to monitor sanding effectiveness during the refinishing process. When a guide coat is applied, it provides a contrasting color that helps the technician easily see where sanding has occurred. As the technician sands the surface, the guide coat is removed from the high spots, revealing any low spots or imperfections that need further attention. This ensures an even surface finish and helps achieve the desired quality in the paint application. By identifying these areas, the technician can make necessary corrections before applying the final paint layers, leading to a smoother and more professional finish.