How to Cure a Gel Coat

Clean the fiberglass surface thoroughly with a cleaning solution and a clean cloth, wipe it with acetone using another cloth and dry it completely. Cleaning the surface will properly prepare it before you apply the first gel coat.

Apply the gel coat using steady, even strokes at a thickness of about 20 millimeters. To apply the gel coat, you can use a pressure pot, catalyst injection, standard paint gun with a primer nozzle, a Preval sprayer, a brush or a roller. Wait 17 to 20 minutes for the gel to cure before applying another layer. No more than two to three applications are necessary.

Sand the surface with sandpaper between coats if you are using a finish gel coat or a polyester gel paste because these types of gel coats require a rough surface for curing. Laminating gel coats bond to smooth surfaces, so you don't need to do anything between coats if you are using a laminating gel coat.

Smooth out the surface using acetone between coats if any bumps, bubbles or uneven surfaces appear in the gel. If you are using a finish gel coat or polyester gel paste, sand the entire surface before applying the next gel layer; if you are using a laminating gel coat, you can apply the next layer after the previous layer is dry.