What indicates that there is no clearcoat on the sanded surface?

The presence of dust that is the same color as the paint indicates that the clearcoat has been sanded away, exposing the underlying color coat. When a surface is cleared and sanded properly, the clearcoat typically produces a different type of dust compared to the color coat beneath it. If the dust matches the color of the paint, it means that the clearcoat layer has been removed, allowing the color coat underneath to be affected during the sanding process.

Having dust that is white often occurs when sanding clearcoats that are still intact or when materials like primers are sanded. A rough surface texture can be a result of excessive sanding or improper technique but does not specifically indicate the absence of clearcoat. Similarly, paint peeling is generally associated with poor adhesion or improper preparation but is not a direct sign of a missing clearcoat on a surface being sanded. Thus, observing dust the same color as the paint is a clear indicator that the clearcoat is absent.