Keep Plastic Out of the Landfill and Make Fun, Freeform Slab Bowl

Turn a plastic bowl into a simple hump or slump mold!

slab bowl
There is no shortage of plastic containers in our world and all too many of them wind up in the landfill. But you can do your part and repurpose them as molds in the studio! 
In today’s post, an excerpt from From a Slab of Clay, Daryl Baird shares how to make a great free form slab bowl using a plastic dish as a mold. –Jennifer Poellot Harnetty, editor.


Small plastic trays containing microwaveable food come in a variety of shapes and sizes. With a little preparation these can be used as slump molds for quickly making a collection of dishes, trays, and teapot bases.

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This article was also excerpted from From a Slab of Clay , which is available in the Ceramic Arts Network Shop!


slab bowl

1. Stack three identical food trays together to create a rigid mold. Lightly dust the top tray with corn starch and spread it evenly.

slab bowl

2. Roll out a ¼- to 1/2 in. thick slab about 25% larger than the mold and decorate it with stamps and roulettes. Carefully coax it into the tray.
slab bowl

3. Lay a dry cleaning bag over the clay to make it easier to press into the corners of the mold. This also helps protect the textures.
slab bowl

4. Trim some but not all of the excess clay. Tuck and smooth the edges to give it a more finished look without losing the freeform shape.
slab bowl

5. Fashion handles from scrap pieces and attach with slip. Additional texture is applied to each handle.

slab bowl

Examples of three pieces made from plastic microwave slump molds.

**First published in 2015.
Comments
  • Hi Eveyln, I recommend taking the plastic off before it is bone dry. As clay dries, it shrinks and will likely cause cracking. Additionally, firing plastic in kilns isn’t a great idea (for you or your kiln!), especially if you don’t have a well ventilated kiln. Hope this helps!

  • Hi Eveyln, I recommend taking the plastic off before it is bone dry. As clay dries, it shrinks and will likely cause cracking. Additionally, firing plastic in kilns isn’t a great idea (for you or your kiln!), especially if you don’t have a well ventilated kiln. Hope this helps!

  • Patricia B.

    Evelyn Tenne, no, you don’t fire them with the plastic. The corn starch is to help you separate the clay from the plastic mold.

  • Patricia B.

    Evelyn Tenne, no, you don’t fire them with the plastic. The corn starch is to help you separate the clay from the plastic mold.

  • Evelyn T.

    A question please……..do you fire them with the plastic? If so, does it affect the kiln or other pots? Just wondering……thanks.

  • Evelyn T.

    A question please……..do you fire them with the plastic? If so, does it affect the kiln or other pots? Just wondering……thanks.

  • Great tips – will help make my next piece (made from a plastic microwave slump mold) MUCH better! Thanks for sharing!!

  • Great tips – will help make my next piece (made from a plastic microwave slump mold) MUCH better! Thanks for sharing!!

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