How to Make a Homemade Gel Coat From Bondo

A gel coat is a specialized resin often used for the surface coat on fiberglass products. It is thicker than standard resin, allowing you to build up a solid shell before adding layers of fiberglass. You can make your own gel coat using fiberglass resin and Bondo auto body filler. This gel coat has a pink color, and makes it easy to visually inspect for thin spots. The mixture is also often less expensive than commercial gel coat.

Mix your own homemade gel coat.

Things You'll Need

  • Bucket with lid

  • Bondo auto body filler

  • Polyester fiberglass resin

  • Paint stick

  • Marker

  • Bondo catalyst

  • Resin catalyst

  • Paper bucket

Step 1

Empty a container of Bondo auto body filler into a 1 gallon bucket with a snap-on lid.

Step 2

Add an equal amount of fiberglass resin to the Bondo.

Step 3

Mix the two components together into a creamy paste using a paint stick. Mix slowly to avoid introducing air bubbles.

Step 4

Seal the lid onto the bucket. Use a marker to write the amount of catalyst required from both the Bondo and resin instructions onto the bucket.

Step 5

Store the mixture in a cool place.


To use the homemade gel coat, measure out the amount that you need in a paper bucket. Mix in the proper amount of both Bondo catalyst and resin catalyst, following the mixing ratios that you copies from the original containers.