What does "shrinkage" refer to in the context of body filler?

Shrinkage in the context of body filler refers to the process where the filler contracts as it cures. This phenomenon occurs because as the chemical reactions within the filler take place during the curing process, it loses some volume due to the evaporation of solvents or air pockets being eliminated, causing the material to shrink slightly.

Understanding shrinkage is crucial for automotive technicians because it impacts the overall appearance and finish of repairs. A filler that shrinks too much can create low spots or imperfections, requiring additional filler to be applied or leading to a time-consuming repair process to achieve a smooth and even surface.

In this context, the expansion of filler as it cures, the application technique of filler, and the color change of filler during drying do not accurately represent what shrinkage actually means. While there may be other factors or characteristics associated with filler, the key concept of shrinkage specifically pertains to the contraction that occurs, making the identification of this term essential for effective bodywork.