How to Sand Bondo

By Kimberly Johnson

Bondo is a paste-like product traditionally used to repair dents, holes and rust-damage in automobiles, but it has a wide variety of other uses as well. The paste forms a hard surface as it dries which disguises surface irregularities and can be primed and painted. However, before applying primer and paint, you must sand the Bondo so it blends in with the surrounding material.

List of Items Needed

  • Safety glasses
  • Dust mask
  • Rotary tool with sanding accessories
  • Rag
  1. Feel the Bondo to see if it is completely dry. Sanding the Bondo too soon gums up sanding materials.

  2. Examine the Bondo to determine if it rises above the surface by only 1/4-inch, or whether a thicker layer exists. Sand with a medium grit accessory if the layer is thicker than 1/4-inch. Sand with a finer grit if it is less than 1/4-inch in thickness.

  3. Sand the surface with a rotary tool, concentrating on the center of the Bondo and using alternating directions. Keep sanding until the Bondo is level with the surface of the surrounding material.

  4. Switch to a finer sanding grit and lightly sand the edges of the Bondo to feather them out evenly into the surrounding surface. Continue until the edges are indistinguishable from the surface below.

Tips and Warnings

  • It helps to wipe off the sanded area periodically with a rag so you can see it better. If you have an air compressor, simply use the air to blow the sanding dust off.
  • Wear dust mask and safety glasses. Sanding Bondo creates quite a bit of dust.

© Demand Media 2011