What situation can lead to sandscratch swelling?

Sandscratch swelling occurs when new finishes are subjected to conditions that cause the solvents in the paint or clear coat to not evaporate properly. When a new finish is exposed to cold shop conditions, the drying and curing processes are inhibited, which can lead to solvent entrapment beneath the top layers of paint. This entrapment causes swelling or bubbling that becomes visible as a result of the heat generated during the curing process and the inability of volatile solvents to properly escape.

In contrast, while excessive heat during drying can introduce issues such as uneven curing, it is not directly linked to sandscratch swelling in the same way as cold conditions. Application of thick layers of paint can also create problems, but primarily related to running or sagging rather than swelling. Finally, using the wrong types of solvents typically causes issues like incompatibility or improper adhesion, but it is not a direct cause of sandscratch swelling under normal drying conditions. Thus, the influence of cold shop conditions on the solvent evaporation process is the key factor leading to this type of defect.