search  current discussion  categories  wanted/for sale - wanted 

fw: re: looking for turquoise high fire glaze

updated fri 20 jul 01

 

Dave Finkelnburg on wed 18 jul 01


John,
I am absolutely no glaze guru, so take this comment for the little it's
worth. :-)
I expect this glaze will be satin if not matt at cone 10, due to the
shortage of silica.
I'm not sure what will happen at cone 6, but I suspect, given the
relatively low potassium and sodium, this is not going to melt terribly well
at cone 6. The calcium and magnesium are quite refractory on their own and
need a fair bit of low-melting fluxes to be pulled into the melt at cone 6.
For the benefit of folks just dropping in on this thread, the Seger
formula I calculated with Insight is below.
Dave Finkelnburg

Weiser Turquoise
CaO 0.37*
MgO 0.36*
K2O 0.19*
Na2O 0.08*
Al2O3 0.36
SiO2 2.39

From: John Weber

>OK, I am trying hard to learn how to use Insight so I put this glaze into
it
>and then compared the results with the Limits published by Green & Cooper.
>This glaze calculates out to contain Si 2.40 and Al203 .37 . The limits
for
>Cone 10 are Si 3.50 to 6.40 and for Al203 .45 to .825. Showing the glaze
to
>be way too low on both Si and Al203. However, when I look at Cone 6 limits
>is shows the range to be Si 2.40 to 4.70 and Al203 from .275 to .65. If I
>believe these limits it would tell me this is not a Cone 10 glaze but a
Cone
>6 Glaze.

>> Behalf Of Dale Neese
>> Sent: Tuesday, July 17, 2001 3:40 PM
>> Here is a Turquoise cone 10 that has been around awhile.
>> WEISER TURQUOISE
>> CUSTER SPAR 63
>> DOLOMITE 24
>> BALL CLAY 9
>> FLINT 4
>> COLBALT CARB .5
>> CHROME OX. 1.5
>> add your favorite suspension agent because this glaze will tend
>> settle like concrete if not used regularly. Nice on porcelain as well as
stoneware.