Sand casting is a process of creating concrete or clay sculptures, containers and other decorative objects using builder's sand as the mold. The basic steps involved in sand casting are the same; the only variations are in the type of mold that you create. Deep molds for casting planters and garden ornaments require a taller pile of sand than more shallow molds for birdbaths or bowls. Commercial molds are available for a variety of sand casting projects. You can also use common items, such as wastebaskets, coffee cans and large leaves to make sand molds for your designs.
Instructions
1. Set up a flat work surface large enough to contain the sand pile. Your work surface can be a sheet of plywood stretched between two wooden horses or a concrete driveway.
2. Pile builder's sand in the center of the work surface. The center of the sand pile should be at least three inches deeper than the height of your mold. If you are making a bird bath from a large leaf, pile the sand three inches deeper than the desired depth of the birdbath. Dampen the sand with water. Slightly wet sand holds a shape better than dry sand.
3. Make an impression in the center of the sand pile with the mold. Make sure that you leave at least three inches of sand beneath the mold. Build the sand up around the mold for support.
4. Remove the mold. Check the sand impression for cracks or spaces. If necessary, fill in the spaces with sand and smooth the cracks with your fingers. Re-insert the mold if necessary. The outside of your finished product will only look as good as the inside of your mold. Spend time making sure that the shape of the sand mold looks good.
5. Cover the sand mold with plastic wrap. Make sure to press the plastic wrap into the contours of the sand mold. Coat the plastic with a release agent. Commercial spray release agents are available, but non-stick cooking spray or spray oil works.
6. Prepare the concrete mix according to the package directions. You can also cast the sand mold with homemade clay or modelling clay. Pour the mixture into the sand mold. If you are casting deep molds, tamp the concrete down with a tamper as you go. Pay attention to the sand walls around the mold, pat them or wet them as needed to keep them firm.
7. Wait four days before removing the concrete from the sand. Wait an additional week before painting or attaching object onto the cast concrete.
Tags: sand mold, sand pile, three inches, work surface, around mold