Mix the casting material. The method of preparation depends on your choice of material for the sculpture. If using plaster, mix one part plaster with two parts cold water. Obtain slip-casting clay by mixing two parts of clay with one part water.
Stir continuously with a wooden a stick until you obtain a paste that is liquid and pourable. Add some color if you want to obtain a colored sculpture. Use natural pigments or oxides.
Strain the clay slip using a large flour strainer and allow the clay slip to mature for 72 hours. If using plaster, start the casting procedure immediately, because plaster hardens within a few minutes.
Join the mold. The mold contains several parts, so that the sculpture can be removed after it hardens without having to destroy the mold as in the case of metal casting. Put the mold with the hole on the top side.
Cast the liquid material to fill half the mold. Tap the mold on the sides to remove bubbles.
Fill the rest of the mold and put the mold aside overnight to allow the material to dry in the mold.
Remove the parts of the mold to uncover the sculpture.
Trim the sculpture using a coarse-grit sandpaper and smooth the surface with fine-grit sandpaper.