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"s" crack musings (continued)

updated sun 15 apr 01

 

Llewellyn Kouba on sat 14 apr 01


Jessica,

Remember also that along with good compression techniques another one not
to forget is : When you tool things be sure you don't do it too early
before the bottoms are really set. You can also move the bottom ever so
slightly without even knowing it- especially on plates or larger pieces and
they will sure enough crack in the bisque. you may not visually see it in
the drying but the weakened spot is there and you have a crack. It is now
a rare event for me to either 'S' crack or crack them in tooling. This all
gets better as you move along and eventually it won't be a problem at
all. Good Luck in your pottery fun

Llewellyn



At 11:24 PM 4/13/2001 -0700, you wrote:
>New to throwing but already an expert in creating s-cracks - and
>trying to move on to more interesting classic pitfalls - I've been
>told they're related to compression and also to clay's 'memory'.
> An article in PMI suggested reversing the wheel now and then, to
>compensate for the one-way torque on the clay when forming flat
>pieces like plates. I'd guess the lower incidence of cracks with
>slabs (if true) could be at least partly because the rolled clay's
>been compressed like crazy, but without a twist that will "want" to
>untwist once it's released (as in thrown ware).
>
>Meanwhile, I just compress like the dickens when I throw plates and
>bowls lately, and seem to be having better luck. So far. This week.
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> "It's not that children are little scientists but that
>scientists are big children."
> ---"The Scientist in the Crib" by Gopnik, Meltzoff, and Kuhl
>
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