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: about crazing

updated wed 2 oct 02

 

iandol on mon 30 sep 02


Dear Martin Rice,=20

The processes and the materials you describe sounds like a disaster =
waiting to happen. Introducing the additional heat of the dishwasher =
ensured that it did.

Earthen ware needs to be fully sealed to ensure that water does not get =
into the residual porosity. This alone will cause the body to expand =
against the glaze and induce tension crazing. Having Calcium Carbonate =
in the clay will also induce expansion of the clay when the interior =
gets wet. During firing it becomes Calcium Oxide. This reacts with water =
to generate Calcium Hydroxide which has a larger volume. CrUnCh!

Sorry to say, this does not seem to be a good clay body for they work =
you intend doing.

Best regards, and good wishes for success,

Ivor Lewis. Redhill, South Australia