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glazing-- will crackles beh

updated wed 12 nov 97

 

Marcia Kindlmann on mon 10 nov 97

Subject: glazing-- will crackles behave?

Joyce in the Mojave asks about some pots where the glaze has dried
with cracks in it,

> These "crackles" sort of lift from the pot. In your experience, will
> this glaze pull further away from the pot and leave blank spaces when
> fired? Or will it flatten out and cover the bowl?

My experience is they'll fly off the pot, leaving, alas, bare spaces on
the pot and places on the kiln shelf where you're glad you used kiln
wash.

_Sometimes_ I have been able to get these flakes to adhere to a pot by
misting with water to re-dampen the raw glaze, then smoothing down with
fingers, then with a brush dampened with a bit of the glaze highly
diluted with water. Fussy, fussy, fussy, but it still takes less time
than scraping all the glaze off the pot & re-glazing.

Perhaps others can suggest ways of altering the glaze mix for less
shrinkage in drying, for next time. Or maybe thinning the glaze would help?
(unless it has to be applied thickly to get the desired color).

Marcia

Barbara Lewis on tue 11 nov 97

Is this phenomenon a result of glazes with a lot of Gerstley Borate? Barbara

At 08:57 AM 11/10/97 EST, you wrote:
>----------------------------Original message----------------------------
>Subject: glazing-- will crackles behave?
>
>Joyce in the Mojave asks about some pots where the glaze has dried
>with cracks in it,
>
>> These "crackles" sort of lift from the pot. In your experience, will
>> this glaze pull further away from the pot and leave blank spaces when
>> fired? Or will it flatten out and cover the bowl?
>
>My experience is they'll fly off the pot, leaving, alas, bare spaces on
>the pot and places on the kiln shelf where you're glad you used kiln
>wash.
>
>_Sometimes_ I have been able to get these flakes to adhere to a pot by
>misting with water to re-dampen the raw glaze, then smoothing down with
>fingers, then with a brush dampened with a bit of the glaze highly
>diluted with water. Fussy, fussy, fussy, but it still takes less time
>than scraping all the glaze off the pot & re-glazing.
>
>Perhaps others can suggest ways of altering the glaze mix for less
>shrinkage in drying, for next time. Or maybe thinning the glaze would help?
>(unless it has to be applied thickly to get the desired color).
>
>Marcia
>
Barbara Lewis
5412 Well Spring Road
La Plata, MD 20646
blewis@crosslink.net
(301) 932-3915