D McMillen on sat 22 jul 00
I have researched the archives but am still a little unsure of the
conclusion of the use of Colemanite as a sub. for GB. It seems there has
been discussion regarding the colemanite pooling off the pieces onto the
shelves. I have also experienced this. ( I fire to cone 10, reduction) Do
you sub equal amts of Colemanite for GB? Would like to hear some comments,
sorry if this is repetitive. I am interested in the "Gillespie Borate". I
did email them for a sample today.
thanks
Dixie McMillen
In Mississippi, where it is just plain HOT
GURUSHAKTI@AOL.COM on sun 23 jul 00
These materials have been substituted for each other. Although they contain
different fluxes, the fluxing action of both is so similar as to usually make
them good substitutions for each other; but ---- always test, test , test.
These materials are known to be very variable in their chemical make up, from
one mine batch to the next. What may work in one persons glazes with one
batch may not work in another's. One recipe may have a bit more temperature
tolerance than another. The only way to know is to test your recipe with your
materials, your water, your clay and your firing method.
Regards,
June
Donald G. Goldsobel on sun 23 jul 00
When I first started making glazes in the 70's, the colemanite source was
gone. I was told by the people at Westwood Ceramics- now Laguna, that a one
for one substitution of Gerstley Borate was the thing to do. I have had no
problems with any recipe that called for colemanite and using GB as a
subsitute. This Gillespie Borate sounds interesting. We can pool our test
sample results.
Donald in the record breaking heat of the San Fernando Valley.
At 03:56 PM 07/22/2000 -0500, you wrote:
>I have researched the archives but am still a little unsure of the
>conclusion of the use of Colemanite as a sub. for GB. It seems there has
>been discussion regarding the colemanite pooling off the pieces onto the
>shelves.
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