How to Build a Fiberglass Automobile Body

The body of a homemade go-kart style automobile can be made out of fiberglass and look just like an on-road car's steel body. Once you have the chassis and frame complete on your car design, you can use sheets of urethane foam and fiberglass coating to create a body that will give you a sturdy and stylish car.

Things You'll Need

• Plywood
• Urethane foam
• Polyester fiberglass
• Completed automobile chassis
• Felt marker
• Plastic strips
• Razor knife
• Solvent-based cement
• Sanding block
• Particle respirator
• Six-ounce fiberglass cloth
• Polyester laminating resin
• Bristled paintbrush
• Portable reciprocating saw

Instructions

1. Plan out every little detail of the car body. This includes not only the shape of the body, but also which pieces and panels of the body need to be assembled in which particular order. Take the structure of your design into account and determine which areas will and won't be accessible when each body panel is in place.

2. Cut out plywood formers and apply them to the chassis with nuts, bolts and brackets. There are at least four formers: One at the front end, one separating the hood and seating compartments, one separating the seating compartment and trunk, and one at the rear end. Their exact placement depends or your car's design and where attachment is convenient, but they should be attached with the chassis at riding height.

3. Place temporary stringers that stretch from one former to the next along the outer edges. These will help you see the car body's shape. The stringers can be plastic strips or anything sturdy yet flexible. Line up the foam pieces with the stringers and trace lines on the pieces with a felt marker to outline the body panels they'll be cut into.

4. Cut the foam into the body panel shapes with a razor knife. You should cut them into a larger shape and then shape them to fit with a sander while installing them.

5. Assemble the foam body parts onto the vehicle. It's usually best to complete the exterior before moving on to the interior details, starting with the floorboard and working upward. Use a solvent cement to paste the panels to one another.

6. Add details to the exterior body once it's completely assembled, using the sanding block. Round off the panel pieces at the edges to remove a panelized image and give the car a better shape. Outline the windows and doors and then sand down areas in the foam where these openings will be cut out.

7. Apply the fiberglass coating to the body. Lay a sheet of six-ounce fiberglass cloth over the exterior and apply polyester laminating resin to the sheet using a bristled paintbrush. Add a second fiberglass sheet and resin coat over the first layer. Add extra layers along the car's back side, the inside corners and any place where you sanded the foam down very thin. The body must be completely coated with no exposed plywood or foam.

8. Cut out the doors and windows from the body with a portable reciprocating saw. You must do this after applying fiberglass to the exterior to ensure the car retains its shape. Once the openings are cut free, apply the fiberglass to the cutoff and inner edges of the body panels.

9. Assemble the body's interior components, like the dashboard and seating compartment. Use the same process of cutting and affixing foam panels and then applying the fiberglass coating. You must know where details like rain gutters, flanges, attachment fixtures like the steering column and the seats will all be within the car and install the interior panels to accommodate them.

Tips & Warnings

• You should wear a wear a particle respirator while sanding the foam panels to avoid breathing in any foam particles in the air.