iandol on wed 30 jan 02
Dear Bill Hanke,=20
You say <and fall off. Why doesn't it do this with a little tiny rock, ie. =
grog?>>
What evidence have you to prove that this does not occur on a =
microscopic scale?
If the Pundits are correct saying that grog opens the clay and allows it =
to dry faster, the presence of fissures and crevices around the =
particles of grog due to that sort of shrinkage must provide the =
pathways.
Break open a piece of well grogged clay and look at it with a X 10 hand =
lens. Tell us all what you see.
Best regards,
Ivor Lewis.
Snail Scott on thu 31 jan 02
At 04:55 PM 1/30/02 +1030, Ivor wrote:
>If the Pundits are correct saying that grog opens the clay and allows it
to dry faster, the presence of fissures and crevices around the particles
of grog due to that sort of shrinkage must provide the pathways.
>
This makes some sense to me. My personal observations
seem to confirm the faster, more even drying of groggy
clays, but I could never account for how the addition
of nonporous pieces of material could account for the
higher apparent permeability of the resulting clay body.
(Or is 'permeability' even a part of all this?)
I'd love to hear further research on the subject!
-Snail
Brant Palley NMCLAY.com on fri 1 feb 02
Large grog (16-20 mesh) can pop out of a bisqued clay body, the underfired
clay not being strong enough to contain the large particle. The same clay
body, fired to maturation, will show no pop outs.
Just an observation.
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