Nan Lopez on tue 27 nov 07
I made a 3000 g batch of one of my favorite glazes. It is a lime green,
transparent glaze that makes interesting blends with other glazes. But it
turned out way too dark grren. So I made up another 500 g without
coloring oxides, added it to the original and tested the new mix on a
small bowl. The color turned out perfect, but the glaze was very flawed.
There was a series of about 8 horizontal cracks, much more prominent where
the glaze was thicker, beginning about one inch below the rim, ending
where it flattened out at the bottom. It does not look like crazing, but
I couldn't find a name for it in either of my reference books (Rhodes and
Fraser). What is it and is there anything I can add to the bucket to
correct it? Here is the recipe:
FF 3110 4
FF 3124 24
petalite 22
EPK 18
whiting 10
flint 20
zinc 5
bentonite 2
coloring oxides: rutile 1.2; copper carb .8; RIO .4
Thanks in advance,
Nan Lopez
Clay Pot Farm
Bullet Tree Falls
Belize
Ron Roy on thu 29 nov 07
Hi Nan,
The expansion of your glaze is low so I'm thinking your problem is a form
of shivering - glaze winds up to big for the clay.
I would suggest relpacing half the Petalite with Custer - 11 Petalite and
11 Custer. Same glaze but with a higher expansion.
You can also try a batch replacing all the Petalite with Custer to mix
equal parts with the glaze you have thats acting up.
Let me know if you need more on this.
RR
>I made a 3000 g batch of one of my favorite glazes. It is a lime green,
>transparent glaze that makes interesting blends with other glazes. But it
>turned out way too dark grren. So I made up another 500 g without
>coloring oxides, added it to the original and tested the new mix on a
>small bowl. The color turned out perfect, but the glaze was very flawed.
>There was a series of about 8 horizontal cracks, much more prominent where
>the glaze was thicker, beginning about one inch below the rim, ending
>where it flattened out at the bottom. It does not look like crazing, but
>I couldn't find a name for it in either of my reference books (Rhodes and
>Fraser). What is it and is there anything I can add to the bucket to
>correct it? Here is the recipe:
>FF 3110 4
>FF 3124 24
>petalite 22
>EPK 18
>whiting 10
>flint 20
>zinc 5
>bentonite 2
>
>coloring oxides: rutile 1.2; copper carb .8; RIO .4
>Thanks in advance,
>Nan Lopez
>Clay Pot Farm
>Bullet Tree Falls
>Belize
>
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Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
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