What is a "filler" and when is it used?

A filler is a substance specifically designed to fill in dents, scratches, and other imperfections on a vehicle's surface before the painting process begins. This material ensures that the surface is smooth and even, allowing for a more professional finish once the paint is applied. Fillers are crucial in auto body repair because they help restore the vehicle's original shape and integrity.

When utilizing a filler, it is commonly applied after sanding down the damaged area but before any paint or primer is applied. This step is vital to achieving an aesthetically pleasing result, as any unevenness or flaws in the surface can become apparent once the final coat of paint is applied. The filler not only aids in cosmetic repair but also contributes to the overall durability and protection of the area being repaired.

In contrast, the other choices relate to different aspects of the repair and refinishing process. Tools for smoothing paint surfaces, primers for paint adhesion, and protective sealants each serve unique functions but do not fulfill the role of filling and evening out surface imperfections like a filler does.