Select the object you want to make a mold of. This is called your model.
Set the model on a surface where it cannot roll or knock over easily.
Break off the clay you will use to cover the model. Ensure that you have enough clay to cover the model completely with a 1/8- to 1/4-inch layer of clay, plus extra to work into all the crevices.
Spray water over your model or gently dust cornstarch over it before applying the clay. This prevents the clay from sticking to the model.
Condition the clay by manipulating it with your fingers until it reaches optimal consistency for working. When you manipulate the clay, the warmth of your hands and the stretching and shaping of the clay makes it softer and easier to shape.
Cover the model with the clay, gently pressing the clay so it gets a solid impression of the model.
Peel the clay from the model gently and wipe off the powder or water carefully so you don't lose the impression.
Cure the clay by placing the clay mold on a cookie sheet and placing it in an oven. Bake it for approximately 25 minutes at a temperature between 265 and 275 degrees Farenheit.
Remove from the oven and let cool.