How to make faux fiberglass rock

Updated February 21, 2017

Faux fibreglass rocks are features that have become increasingly useful around the home or garden. They can be made to any shape size or colour, giving them a variety of uses from decorative garden placement, to functional cover of unsightly landscaping features. The process of making a faux fibreglass rock is a simple one, requiring the same skills used in creating papier-mache, only with a final layer of fibreglass cloth rather than newspaper. Once your rock has been built, the fibreglass surface can then be painted whatever colour desired.

Make the frame for your rock using chicken wire. Cut a section of the chicken wire using wire cutters and bend the wire into the shape of your rock. Twist the loose ends of the wire together using pliers to bind the edges and complete the rounded shape of the rock.

Cut newspaper into strips of two inches in width. Use a paintbrush to apply art paste to the newspaper strips soaking the strips through. Apply the strips to the wire shape, covering the wire completely with two layers of newspaper, with the second layer applied perpendicular to the first. Overlap the strips of newspaper about one-half inch when applying and allow the newspaper to dry for six hours after each layer has been placed.

Cut the fibreglass cloth into strips two inches in width and eight inches in length for easy application. Use a rotary cutter with a new cutting wheel to cut the cloth.

Mix the resin according to the manufacturer's instructions. The resin thickens as it dries, so only prepare enough for 10 minutes use at a time. Wait three minutes for the resin to activate fully before application.

Place a strip of the fibreglass cloth over the papier-mache rock, following the contours of the wired frame. Pour the resin over the strip and use a craft stick to spread the resin over the surface of the cloth. As you spread the resin, bunch and wrinkle the cloth randomly to simulate the natural textured surface of a rock. The resin will soak through the fibreglass cloth adhering it to the papier-mache surface beneath. Repeat the application process with more strips of the fibreglass until the rock is completely covered.

Wait 24 hours for the resin on the fibreglass to cure, and then sand down the visible seams between the fibreglass strips.

Prime the rock with a base coat of latex paint. Brown or grey is best depending on the type of rock simulated. Use brown for darker stones and grey for lighter types.

Allow the prime coat to dry for two hours and then paint the rocks with a final coat, the colour depending on the rock type being simulated. Apply a light wash of diluted paint with a ratio of nine parts thinner to one part paint to the final coat to weather the rock and enhance shadows in the various wrinkled and bunched areas. Allow the final coat to dry for two hours.

Spray the rock with a layer of matt clear coat spray paint to protect it from the elements.

Things You'll Need

  • Hex (chicken) wire
  • Wire cutters
  • Pliers
  • Newspaper
  • Scissors
  • Paintbrush
  • Art paste
  • Fibreglass cloth
  • Rotary cutter
  • Resin
  • Craft sticks
  • Squeegee
  • Latex paint
  • Clear coat spray
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About the Author

Larry Simmons is a freelance writer and expert in the fusion of computer technology and business. He has a B.S. in economics, an M.S. in information systems, an M.S. in communications technology, as well as significant work towards an M.B.A. in finance. He's published several hundred articles with Demand Studios.