Sand casting is making decorative pieces of art from plaster that has been cast in a mold of damp sand. Ocean sand found at the beach is best because it is a fine grain sand, which achieves the best detail. But sand purchased from gravel companies or a home and garden store will work.
In the damp sand draw the outline of your mold idea, lightly on the surface with a pencil. Then using a spoon, dig out the shape about a half-inch deep, putting the sand into the empty bowl. It can be reused for future sand cast art pieces. Make sure that the walls of the mold are firm and that the bottom is flat and smooth, and the walls should be firm.
Once you have your mold you can use any "gadget" to give the desired decorative look. Imprints of spools of thread, lids of pencils, buttons, game pieces, anything you can think of that will leave a print in the sand. Edges of cardboard are great for lines.
You may press beads or tiles into the sand for accents. Pieces of mirror can be used to. To this place the mirro face down onto the sand. DO NOT press it into the sand. Create a ridge or frame around the mirror using a piece of cardboard to "trace" around the mirror. To create a recessed look with the mirror, create a 1/16 " high flat mound in the shape of the mirror. Then place the mirror on the mound to raise it.
To mix plaster, spoon plaster into a half gallon milk container that has been cut down and filled with water. Do not stir plaster until it mounds up on the surface. Then, using a wooden spoon stir until it is a thick liquid. There should be no powder residue.
Slowly and carefully pour the liquid quickly into each mold. This should NOT been done in the sink. Plaster can clog a drain. After a few minutes, the plaster begins to set up. At this time you can insert a wire loop or bent hair pin into the center top of the mold. These will make your art piece easier to hang for display.
Let plaster dry for up to 24 hours. Then carefully pry piec out of sand. Wash in warm water. Use a toothbrush or any other smallbrush to remove excess sand.