Practice question · Multiple choice
Why does joining two pieces of clay at different moisture levels usually produce a crack?
Hints
- Ask what happens to each piece as it loses its shrinkage water.
- A drier piece has already shrunk; a wetter one has not.
Show the answer
B. They shrink by different amounts as they dry, so the join is pulled apart
Why
Because they shrink by different amounts. The drier piece has already lost part of its shrinkage water and the wetter one has not, so as drying completes the wetter piece contracts against a neighbour that no longer moves. Joining at the same stage, usually leather-hard, is the standard answer.
Practise Clay: What It Is and Why It Shrinks
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