Slip Casting

Using plaster molds

Objective:

To create sculptural forms using slip casting molds. 

Requirements:

Cast from three different molds.

Glaze the final sculptures.

Supplies:

Clay, water, rubber bands, slip container, plaster molds, glaze, brush, and plastic bags.

Terms:

Slip: An opaque, creamy liquid made by mixing finely ground clay with water. Slip is an inevitable byproduct of working on a potter's wheel, its name having resulted from potters' use of water to keep the spinning clay slippery as it's worked. It is also used in the making of pottery to cement together parts that have been formed separately; in slip casting, and in decorating surfaces.

Casting: Slush casting by pouring slip into a plaster mold, and then leaving it until a thick skin forms inside the mold. The excess slip is poured out and the hollow cast left to harden. It was introduced into many European porcelain factories in the eighteenth century, and was commonly employed for the casting of terra cotta sculpture in the nineteenth century.

Mold: A hollow form for shaping (casting ) a fluid or plastic medium, such as clay, plaster, plastic or molten metal. In papermaking, the lower screen that holds the pulp (the upper frame is a deckle). Also see core, gelatin, hollow casting, investment, latex, lost-wax casting, mother mold, polyurethane, release agent, and silicone rubber.

Target skills:

Craftsmanship

Patience

Casting techniques

Rubric: Microsoft Word format

Step #1

Use old clay and a container. Add water and mix until it is the consistency of a thin milk shake. Make sure all the lumps are dissolved.

Step #2

Find a mold and scrape off all the old slip. Use rubber bands to fasten the mold together. 

Step #3

Pour slip into the mold. Fill it up to the top.

Step #4

Shake the mold. Make sure that there are not any air pockets. Pour the slip back into the slip container.

Step #5

Repeat step 4&5 two more times. Let the mold sit out to dry for at least 5 days.

Step #6

Remove the objects from the mold. Use a tool to clean-up any damaged areas. Remove the clay line where the mold pieces were joined together.

Examples