iandol on tue 1 apr 03
Dear Terry Sullivan,=20
Thank you for that comprehensive chemistry lesson about getting carbon =
into the fabric of the immature glaze.
I would like to know: How does the openness of the structure of the =
layer of unfused glaze affect this. Is it necessary to use coarsely =
ground materials to ensure that there are holes and interstices through =
which the carbon smoke can percolate? Would using minus 200 mesh =
materials be counter productive?
And a second point. If the Sodium Carbonate is wicking to the surface to =
from a discrete layer, could this form a continuous coherent film like =
ice on water which would act as a barrier to penetration of the smoke.
Best regards,
Ivor Lewis.
Paul Herman on wed 2 apr 03
Greetings Ivor,
I think the trick is to get that carbon in there before the Sodium
Carbonate melts, hence the early reduction (cone 012 or 010) that the
gurus recommend. After melting, it becomes the continuous coherent film
you speak of, blocking the carbon from penetrating.
Normal glaze materials seem to be coarse enough.
Best Wishes,
Paul Herman
Great Basin Pottery
423-725 Scott Road
Doyle, California 96109 US
potter@psln.com
----------
>From: iandol
I would like to know: How does the openness of the structure of the
layer of unfused glaze affect this. Is it necessary to use coarsely
ground materials to ensure that there are holes and interstices through
which the carbon smoke can percolate? Would using minus 200 mesh
materials be counter productive?
>
> And a second point. If the Sodium Carbonate is wicking to the surface to
> from a discrete layer, could this form a continuous coherent film like ice
> on water which would act as a barrier to penetration of the smoke.
>
> Best regards,
>
> Ivor Lewis.
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