How to Finish Painting Fiberglass Show Parts

Go to any auto or hot rod show around the world where modified or custom automobiles are found and you're likely to see fiberglass being used as a building material for auto parts of every shape and size. Fiberglass is an easily molded material. It's string, and a smooth high gloss finish can be painted onto it that's difficult to replicate using most other materials. The process of laying on the paint, and creating the smooth show quality finish is a specific one, with each step requiring implementation time as well as curing time to complete. Once completed however, the type of finish that's possible has no equal in the auto body world, which is why fiberglass parts continue to grow in popularity.

Instructions

1

Sand the fiberglass part with a dual-action sander using 150-grit sandpaper. Move the sander over the part in small circles, removing any coating that may remain from the part-forming process and creating a surface suitable for primer adherence.

2

Examine the part for any imperfections, including scratches or low areas in the surface of the part. Repair these imperfect areas by filling them in with a mixture containing 97 percent fiberglass filler with 3 percent cream hardener. Use a putty knife to press the filler into the damaged areas, scraping over the filler area with the edge of the knife to even the filler area out with the surrounding part surface. Wait 1 hour for the filler to dry.

3

Sand the filler patch by hand using a 150-grit sandpaper to smooth the patched area out with the rest of the fiberglass part. Wipe the part clean with a cloth to remove any sanding residue.

4

Prime the fiberglass part with sandable polyester primer. Apply the primer coat with a paintbrush, building up the primer coat with three or four thin layers of primer paint. Spray the primer coat with a coat of black lacquer paint, and then wait overnight for the primer to dry.

5

Sand the primer coat with 220-grit wet/dry sandpaper attached to a rigid sanding block. Go over the surface of the fiberglass part with the sandpaper until you create a smooth flawless surface. Wipe the sanding residue away with the cloth, and then spray a second coat of black lacquer paint over the part. Allow the part to dry overnight.

6

Wet sand the second black lacquer coat with 400-grit sandpaper, sanding the part until the surface is smooth. Wipe the part with a cloth to remove sanding residue.

7

Use a grease remover applied to the fiberglass part with a clean cloth to remove any oils left on the part during the priming and sanding process from your hands.

8

Paint the base coat of paint onto the fiberglass part. Brush the coat onto the part building it up with three thin paint layers. Dry the part for two hours after applying each layer of paint before applying the next layer. Wait two hours drying time after the final layer of paint before continuing.

9

Spray the fiberglass part with a layer of clear coat paint to keep the base coat from damage. Wait overnight for the clear-coat to cure.

10

Wet sand the fiberglass part with 2,000-grit sandpaper to remove any imperfections in the finish from the painting process. Sand the part using small circles, removing any scratches or unlevel clear coat, while creating a mirror finish in the clear coat layer. Wipe the part with a clean cloth to remove any sanding residue and then wait three hours for the solvents in the paint to evaporate and complete the curing process.

11

Polish the fiberglass part with car polish, applying the polish with a cotton rag and then buffing the dried polish off to create a glossy shine.