How to Pour Ceramics Slip Into a Plaster Mold

This is how to make greenware. The plaster mold absorbs moisture from the slip, leaving a clay shell.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Ceramics Mold Straps Or Rubber Bands
• Clay Slip
• Plaster Molds
• Timers
• Paint Stirrers
• Bowls

1. Make sure the mold is clean and dry.

2. Close the mold, fastening it shut with rubber bands or mold straps.

3. Pour the slip into a container that will hold more than enough slip to fill the mold.

4. Stir the slip with a wooden paint stirrer to be sure that it's mixed well.

5. Pour the slip steadily into the pour hole of the mold. The plaster will absorb moisture from the slip, forming a layer of clay.

6. Keep filling the mold until the drying clay forms a 3/16-inch wall. This is a general rule; the thickness will vary depending on the size of the mold. (Smaller pieces are typically thinner.)

7. When the piece is thick enough, pour the excess slip out of the mold and set the mold upside down over a container (such as a bowl) for about 10 minutes.

8. Turn the mold upright and give the clay time to harden ' 15 minutes or so should be sufficient. You want the piece to be able to stand up by itself without folding or bending when it's removed from the mold.

9. Trim the extra slip from around the pour hole.

10. Put the mold on its side on a flat surface. Gently lift the top half of the mold straight up. If it feels like it's sticking, it isn't dry enough yet ' let it sit another 15 minutes.

11. Let the piece sit for another 5 minutes after the top half of the mold is removed.

12. Turn the piece over in your hand so that the other half of the mold is on top. If the piece still feels soft in your hand, let it dry longer before trying to remove the second part of the mold. If it feels like it can support itself, remove the rest of the mold.

13. Put the greenware somewhere safe, warm and clean to dry overnight.

Tips & Warnings

• Wipe out your mold before and after you use it.

• Securing your mold with the mold straps or rubber bands will prevent warping as the mold dries.

• Don't ever jiggle a mold half to pull it loose. Let the piece dry longer if it sticks.