When I was young, we made sand castings at the beach. One would find shells and rocks to lay into the damp sand and a parent would pour prepared plaster of paris (made with sea water) over the creation. Once the plaster had cured, we would dig out the plaster and have a unique art piece. I wanted my students to try this type of art
For this project, I used damp playground sand into shoe boxes. The students came out of their regular class in small groups to work with me. They dug a small hole in the sand in any shape they chose. They could press things into the sand to create a relief or they could add shells, beads or bottle caps to create their sand casting.
Once the sand mold was complete, the plaster was mixed according to the package directions and then poured into the mold.
When the plaster became thickened a bit, I pressed a paper clip into the plaster to create a way to hang the art and wrote the student’s name so we could easily identify the art.
Because we had a limited amount of boxes and sand, as soon as they were dry enough to remove, we did. We carefully unmolded them and allowed them to dry overnight. Excess sand was brushed off with a paintbrush.
Here in San Diego, we have two public art sand castings made by Charles R. Faust (1922-2000). One is at the San Diego Airport Terminal 1 and one is at the Chula Vista Nature Center. If you get a chance, go look at them. They are simply amazing. There may be others out there by “Uncle Chuck” but those are the two I know of.