What Is Car Body Filler?

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.

Metal Filler

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.

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About the Author

Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.