How to Make a Rubber Stone Mold

When is a stone not a stone? When it is molded in concrete.

The addition of stones to a garden wall or walk gives a touch of nature and craftsmanship. You can create stones by making a reusable rubber mold. You can mold individual stones, but this project teaches how to make a stone "veneer," which is a number of stones grouped together. When the mold is cast, you will have a sheet of rocks that can be placed in the garden or attached to the wall of a house. Once you learn how to make a rubber stone mold, you can make several stone veneers that fit together and will cover an entire wall in no time and without much effort.

Things You'll Need

• Wooden frame with a bottom
• Stones, various sizes and shapes
• Silicon caulk
• Stone sealant
• Release agent
• Epoxy glue
• Clay
• Silicon rubber mix

Instructions

1. Build a wooden frame with a wooden bottom large enough to elevate the stones 1/4 inch and support the mold. Add an additional 1 inch to the frame for the mold edges. Seal the seams of the frame with silicon caulk before pouring the mold. Allow to dry.

2. Seal the stones to be reproduced with a stone sealant used on stone floors and concrete. Allow to dry completely. Spray the stones with a release agent in order to facilitate easy removal from the mold.

3. Apply epoxy glue to secure the stones together into the desired design. Allow the epoxy glue to dry completely.

4. Spread a bed of clay in the bottom of the wooden frame. Place the stones in the clay. Leave 2 inches of the stones showing above the clay. This will form the front of the stone veneer.

5. Mix the silicone rubber mix according to the manufacturer's instructions. Pour onto the stones in the wooden frame covering the stones completely plus 2 inches.

6. Allow the silicone rubber to cure to a solid form in a well-ventilated place overnight.

7. Remove the rubber veneer mold carefully from the stones so as to not tear the mold.

8. Allow the stone mold to dry for another 24 hours before casting the mold.

Tips & Warnings

• You can make a mold of one rock or several rocks at a time.

• Create a "natural" pattern if molding several rocks at a time. Remember that nothing is perfect in nature. Lining up the rocks in a neat row may make the casting process easier but may not look so attractive.

• Do not make your mold too large as it may be very difficult to handle without tearing the mold.

References

• Stone Caster Studio: Molds

Resources

• Techno Industrial: Rubber Molds
• Molds R Us: Types of Stone Molds