What is bondo?

Bondo is a brand name of a type of automotive body filler, specifically a polyester-based filler. Here's some information about it:

• What it is: Bondo is a two-part putty-like substance that hardens when mixed. It's used to fill dents, holes, and other imperfections in car bodies and other surfaces. The two parts are a resin and a hardener. The hardener initiates a chemical reaction that causes the mixture to cure and become solid.

• How it's used: The resin and hardener are mixed in the correct ratio (usually specified on the packaging), then applied to the damaged area. It's typically shaped with a putty knife or similar tool while still wet. Once cured, it can be sanded and painted over to provide a smooth, even finish.

• Advantages: Bondo is relatively easy to use, strong, and adheres well to metal and other surfaces. It's readily available at most auto parts stores and relatively inexpensive. It's good for filling larger imperfections.

• Disadvantages: It can shrink slightly as it cures. It's not as flexible as some other fillers, meaning it can crack if applied to areas that flex significantly. It also requires careful sanding to achieve a perfectly smooth surface before painting. It's not suitable for structural repairs.

• Alternatives: There are many other types of body fillers available, some offering improved flexibility, shrinkage control, or other properties depending on the repair needed. Some alternatives are epoxy-based fillers or specialized fillers for specific materials.

• Safety: Always wear appropriate personal protective equipment (PPE) such as gloves, eye protection, and a respirator when using Bondo, as the fumes can be irritating.

In short, Bondo is a popular and effective body filler for many automotive repair jobs, but it's important to understand its limitations and use it appropriately. For major structural damage, professional repair is always recommended.