How to Form a Fiberglass Car Body

Updated March 23, 2017

Fibreglass car bodies typically find use in car racing and prototype vehicle design projects. Since the body of the car, or skin, simply needs to be strong enough to provide wind protection and make the car aerodynamic, fibreglass bodies can be used for all sorts of experimentation. For the parts to work they need to be shaped so they can be bolted on and attached to the car frame correctly. This takes some work in design to make sure the measurements are correct.

Design the car body with pen and paper. Plan out measurements using a measuring tape, calculator, and the existing car frame. Anticipate in your design where breaks in the body will need to occur so you can assemble the body parts later bolted to the car frame.

Collect enough foam from a materials or art store to create the shape of the car body consistent with your design. Glue the various pieces of foam together to make bigger sections. Cut and sand the foam to match the shape of your car design.

Cut plywood sheets with a saw to create the parts necessary for building a fake car frame. Build the frame to match the car that the fibreglass body will ultimately go on to. Connect the wood pieces together using basic nuts and bolts hardware, securing the hardware with a socket wrench, crescent wrench, screwdrivers and a hammer.

Insert the foam pieces within the frame and on the outside of it to create the mould the fibreglass body parts will shape to. Use glue to hold the foam to the wood frame. Cut the foam as needed with sharp knife or razor. Further sand and trim the foam to meet your design requirements.

Begin coating the frame and foam with a laminate resin while working at indoor room temperature. Lay on sheets of fibreglass as you complete the coating of section. Paint more laminate onto the fibreglass with a paint brush. Repeat the sheet and resin process three to four times all over the foam and frame. Let it dry when finished.

Use a grinder and sander to trim off and shape the dried fibreglass body. Check your design to confirm the proper shape for the body sections. Follow the process of steps two through five for each body part needed. Drill necessary holes and cavities for attachments and connecting the body parts to the actual car frame.

Sand down and round the edges with clay so they are not rough. Wax the entire body part collection and cover it again with another resin coat. Let the parts dry again. Remove the finished body parts from the foam and wood frame. Begin to assemble the car body when finished.


Pay special attention to the surface of the body to ensure it is even and does not have bubbles. Use a roller to smooth out any air pockets while the fibreglass is still wet.


For personal protection never work with fibreglass without wearing gloves, a body suit, eye protection and a respirator mask. Fibreglass resin fumes are toxic.

Things You'll Need

  • Pen
  • Paper
  • Measuring tape
  • Calculator
  • Foam
  • Glue
  • Wood
  • Saw or table cutter
  • Socket wrench
  • Crescent wrenches
  • Screwdrivers
  • Hammer
  • Nuts and bolts
  • Razor or sharp knife
  • Sand paper
  • Fibreglass sheets
  • Fibreglass resin
  • Paint brush
  • Grinder
  • Sander
  • Clay
  • Wax
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About the Author

Since 2009 Tom Lutzenberger has written for various websites, covering topics ranging from finance to automotive history. Lutzenberger works in public finance and policy and consults on a variety of analytical services. His education includes a Bachelor of Arts in English and political science from Saint Mary's College and a Master of Business Administration in finance and marketing from California State University, Sacramento.