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How to Make Faux Rocks From Spray Foam

Faux rocks have a wide variety of uses. They are used in gardens and planters in horticulture. They are used as props in movie scenes and plays, and are found in exhibits and science-fair projects. Additionally, fake rocks can be used to help learn geology. For example, models can be made of igneous rocks, which are formed from cooled lava.

Things You'll Need

Can of spray foam
Cardboard paper or box
Sandpaper
Utility knife
Putty knife
Paint
Paintbrush

Instructions

- 1
  Place the cardboard paper or box on a flat surface. Spray the foam onto the cardboard. Keep adding foam until the rock is the correct size.
- 2
  Smooth and mold the foam with a putty knife, and let it dry. Add more dollops of foam if necessary.
- 3
  Cut edges and gaps into the foam rock with the utility knife. Smooth the surface with sandpaper. The sandpaper also helps give the foam a more grainy appearance.
- 4
  Paint the foam so that it will look like a rock. Use combinations of gray and brown paint, with white and black paint to form shadows and highlights.

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