How to Use Bondo For Car Body Repair

January 27, 2012

In the world of automotive body repair, the product Bondo has become indispensable for filling holes, covering scratches and re-contouring curved surfaces. Bondo, a paintable body filler, can be applied easily to any automotive surface, including metal, plastic and fiberglass, drying eventually into a hard and waterproof surface. The process for performing a Bondo repair is very similar to that of repairing drywall and consists of three basic steps: preparing the surface, applying the putty and finishing the repair with sandpaper.

The most important step to a Bondo repair is surface preparation. Without a dry, clean and dull surface to adhere to, the putty will not form a proper bond to the surface. After the car has been washed clean of impurities, a 120-grit or finer sandpaper should be used to scuff the body parts and remove paint and residual wax. Once the surface is prepared, an supply of Bondo putty should be placed onto a hard board with a putty knife. A small quantity of hardener is then added to the putty and mixed thoroughly. Enough Bondo should be prepared to repair one 2-inch section at a time. Once the hardener is added, approximately 45 minutes remains for the repair to be completed.

Using the putty knife, the putty should be spread on the damaged area and contoured to the curvature of the part. After 45 minutes, the Bondo should be sufficiently dry for sanding. Sand the putty with increasingly finer grits of sandpaper until smooth and wipe with a damp cloth. The Bondo surface can now be primed and painted, after which it should last the life of the vehicle.