What is bondo?

Bondo, also known as body filler, is a putty-like substance used to repair dents, dings, and rust damage in automobile bodies and other surfaces. It's a common material in auto body repair and DIY projects.

• Composition: Typically a two-part system, consisting of a polyester resin base and a hardener (usually benzoyl peroxide). When mixed, a chemical reaction occurs causing it to harden.

• Application: Bondo is applied to the damaged area, filling in imperfections. It can be applied in layers for deeper repairs.

• Working Time: Has a limited working time once the hardener is mixed in, typically a few minutes depending on the ambient temperature and the amount of hardener used.

• Sanding: Once cured, Bondo is easily sandable, allowing it to be shaped and smoothed to match the surrounding surface. Various grits of sandpaper are used, starting with coarse grits to remove excess material and finishing with finer grits for a smooth finish.

• Priming and Painting: After sanding, the repaired area needs to be primed to seal the surface and provide a good base for paint. Then, the area can be painted to match the original color.

• Limitations: While versatile, Bondo is not suitable for all repairs. It's best used for cosmetic damage and should not be used for structural repairs or areas subject to high stress. It also can absorb moisture if not properly sealed, leading to rust or other issues.