What is plastic body filler used for during repairs?

Plastic body filler is primarily utilized in the repair process to smooth out imperfections in the vehicle's surface after the metal panels have been aligned as closely as possible. When a vehicle sustains damage, dents or imperfections are often left behind even after the metal has been worked on. The body filler is applied to these areas to fill in the voids, creating a smooth surface that can be sanded and painted. This finishing process is essential for achieving a seamless repair that is not only aesthetically pleasing but also ensures that the vehicle’s body is uniform and free of defects.

The other options describe functions that do not accurately reflect the intended use of plastic body filler. For instance, while bonding panels together is a crucial step in collision repair, it is typically accomplished using adhesives or welds rather than body filler. Similarly, replacing entire sections of damaged panels involves more extensive techniques like sectioning or welding in new metal rather than simply applying filler. Lastly, creating a protective layer over paint is not the function of body filler; instead, it is intended for surface repair and preparation before the application of paint and clear coat. Therefore, its specific role in filling remaining damage when the metal is nearly in its correct position makes it invaluable in achieving an effective and high-quality repair.