How to Use Bondo on a Smashed Body Panel

Bondo, a two-part polyester resin putty, is used by auto-body repair shops to fix dents and holes in car body panels. When the two parts mix, they chemically bond and turn into a rock-hard substance. Use Bondo on a smashed car body panel to fix the dent and make the surface even and smooth.

Instructions

1

Prepare the surface of the smashed body panel by sanding it down with 80-grit sandpaper and roughing up the surface so the Bondo will stick to it. Remove the sanding dust with a microfiber towel.

2

Mix both parts of the Bondo putty -- one is the filler and the other is the hardener. Knead the tube of Bondo hardener to soften it. Place a golf-ball size of Bondo filler on a non-porous surface, such as a plastic art mixing board. Squeeze out a 1-1/4-inch strip of the hardener onto the board. Mix the two parts together with a paint stir stick until the putty is a uniform color.

3

Pick up the mixed Bondo with a plastic squeegee and spread it across the smashed area of the car body panel, extending the Bondo out onto the surrounding undamaged surface of the panel by about an inch on all sides of the repair area. Apply just enough filler to match the surface of the body panel. Wait 15 minutes for the Bondo to cure.

4

Touch the Bondo. When it's no longer sticky to the touch, sand down the surface to make it even with the surface of the car body panel. Wear a face mask while sanding.

5

Mix more Bondo if you find low spots. Fill in the spots, wait 15 minutes for the Bondo to cure, then sand it even with the body panel.