Body filler application is a process used in automotive repair and restoration to smooth out imperfections on a vehicle's surface. This material, often made from a combination of resin and hardener, is applied to dents, scratches, or rusted areas to create a flat and even finish. After mixing the filler, it is spread over the damaged area using a putty knife or spreader. Once it hardens, the surface is sanded down to match the surrounding area, ensuring a seamless look before painting. Proper application is essential for achieving a durable and aesthetically pleasing result.