How to Make a Fiberglass Hood

Custom fiberglass hood

Making a fiberglass hood is a two-step process. The first step involves building a mold out of the identical hood you want to make. The mold is made with the same materials as the actual hood will be made from. After you have the mold completed, the second step is applying fiberglass mat and resin to the mold to produce the hood replica. If the mold is made correctly, you can get many uses out of one mold.

Things You'll Need

• Original hood
• Boat wax
• Scissors
• Tooling gelcoat
• Gelcoat spray gun
• Air compressor
• Air hose
• Fiberglass mat
• Polyester resin
• Hardener
• Small buckets
• Stir sticks
• Felt rollers
• Air roller
• Paint scraper
• Rags
• 800-grit wet sandpaper
• Respirator

Instructions

1. Find the same model hood that you want to make. Put two coats of boat wax on the top side of the hood. Buff out using a clean rag.

2. Place the fiberglass mat over the hood and cut the mat so it has a 2-inch overhang on all four sides. To make the mold strong, use eight to 10 layers of the standard 1.5 ounce mat.

3. Make sure all the dust is off the surface of the hood (use a clean rag).

4. Mix the gelcoat with the catalyst as directed on the containers. Pour the gelcoat into the gravity feed spray gun. Gelcoat is thicker than normal car paint so you have to make sure the gun sprays gelcoat. Spray the first coat making sure it covers the entire surface. Let stand for 15 minutes or until its tacky. Repeat for all three coats. Let cure.

5. Mix the resin solution with the catalyst as directed. Wet out the surface of the gelcoat with the resin mixture using the felt roller. Add one layer of mat and wet out thoroughly. Make sure there are no dry spots. Go over the entire layer using your air roller, getting all wrinkles and air bubbles out. Let cure for one to two hours or until hard and cool to the touch.

6. Wearing your respirator prepare the hood for the remaining layers of mat by sanding the surface with sandpaper.

7. Make another bucket of the resin mixture. Using the same process as in step 5, add the remaining layers of mat. Let cure.

8. Remove the fiberglass mold from the hood using a paint scraper.

9. Prepare the mold by wet sanding the gel coat with 800-grit sand paper. Make sure all defects in the surface are sanded smooth, or they will show up in all the mold layups. When the surface is smooth, add two to three layers of wax.

10. Mix a bucket of resin and catalyst. Using the same process as step 5, add two layers of mat onto the mold and let cure. Once the first two layers are cured, sand smooth and add the remaining layers as you did in the previous steps.

11. Using the paint scraper break the hood free from the mold. Wearing a respirator, cut and grind to the dimensions of the original hood.

Tips & Warnings

• Always wear safety glasses and respirators when working with fiberglass materials.

References

• Fibre Glast Information
• Fiberglass Warehouse
• Mold Construction Information