Used in practically every type of bodywork that can be done, body filler is an important part of the hot rod universe. Contrary to what a mechanic might say, bodyworks garages use the exact same types of fillers that are available to everyone.
Going by the generic trade name Bondo, polyester body filler is a two-part compound that uses a catalyst to chemically harden the sticky goo in the bucket into a hard, durable plastic.
Applications for Plastic Filler
Plastic filler is used in practically every bodywork application, from collision repair work to factory prep jobs.
Benefits of Plastic Filler
Plastic filler produces a smooth, hard substrate for the primer to stick to and allows even a novice bodyman to cover blemishes in a car's metalwork before painting.
Rarely used, the technique of using molten lead to fill in the joints and cavities between panels has been around as long as the automobile. With its low melting point, low viscosity at temperature and high malleability when hardened, lead solder makes a perfect filler for the custom car artist.
Plastic filler should never be used to fill rust holes or major body defects.