How to Paint Fiberglass Cap

Fiberglass is a common material used to construct many things such as tubs, pools, tanks, cars, planes, truck caps and industrial pipes. The paint that is used on fiberglass is called gel coat. Gel coat consists of fiberglass resin that is pigmented with color and for outside applications there are additives to protect against UV rays. The consistency of gel coat is thick and requires a gel coat spray gun for application. All fiberglass materials can be purchased at a marine supply store.

Things You'll Need

• Respirator
• Palm sander
• Sandpaper
• Clean rags
• Acetone
• Painter's tape
• Gel coat
• Methyl ethyl ketone peroxide (hardener)
• Small bucket
• Stir stick
• Gel coat spray gun

Instructions

1. Put on a respirator and sand the cap using a palm sander and coarse-grit sandpaper. Thoroughly scuff the entire surface so it is dull and smooth. The better the scuff is, the better the gel coat will bond to the fiberglass.

2. Clean the sanded surface using a clean rag and acetone. Remove any grease or dust that's on the surface. Any grease or oil residue that is left on the surface can cause the gel coat to form bubbles.

3. Mask off any windows or metal that's on the cap, using painters tape.

4. Add the gel coat and hardener to the gel coat gun as directed in the manual. If the gel coat gun isn't an internal mixture gun, mix the gel coat and hardener before adding it to the gun. Do this in a small bucket and use a stir stick. Follow the directions on the catalyst container for the correct proportions.

5. Spray the first coat of gel coat onto the cap in a heavy mist. Apply the gel coat as evenly as possible, to avoid runs. Let the first coat begin to get tacky before applying the second coat.

6. Spray the second and final coat onto the cap, solidly covering the surface. Continue to apply the paint in an even and consistent fashion. Let the gel coat cure until it is hard and cool to the touch.

Tips & Warnings

• Always wear a respirator when working with fiberglass materials.

References

• American Marine Supply: Gel Coat Information
• FIberglass Hawaii: Gel Coat Usage