May Luk on sat 21 feb 04
Hiya;
Further to John's comment on controlled cool for different kiln size. Is the
range 1025 - 800 C most crucial? Or it's dependent on the glaze type? I want
to find a middle of the road range as a starting point; a not too
complicated ramp.
Right now, I have a load ful of all sort of glazes- Glossy, matte and such.
Just want to start somewhere, as I don't want to go too slow and have my
stable glossy turn on me.
Many thanks in advance
May
London, UK
Alisa Clausen on sun 22 feb 04
> Further to John's comment on controlled cool for different kiln size. Is
the
> range 1025 - 800 C most crucial? Or it's dependent on the glaze type? I
want
> to find a middle of the road range as a starting point; a not too
> complicated ramp.
>
> Right now, I have a load ful of all sort of glazes- Glossy, matte and
such.
> Just want to start somewhere, as I don't want to go too slow and have my
> stable glossy turn on me.
>
Dear Mary,
I did some testing with John and Ron's glazes where I made 4 tiles of the
recipe Bone.
One set each with the recipe as is and the other with a sub. for the Frit.
One set I fired with the book's ramp on the way down.
The other I fired with a 5 minute hold at the top and then one hour hold at
800c, and off.
I also fired kiln loads with both glosses of various recipes including 20 x
5 and commercial,
and mats with both ramps.
My general findings were that for the mat glazes, the shorter and longer
hold resulted in the same result. A fine mat surface. As J&R say, the mat
surface requires a slow cool for small chains of crystals to form, thus
giving a mat surface.
However, with the longer cooling suggested in the book, I found that
although the clear gloss surfaces were smoothly melted and stayed where
glaze, some of the glosses, esp. those with Cobalt and Iron, became more
fluid than I wanted them to be. They did not run, but some streaked, leaving
clear streaks. With the shorter cooling, the one hour hold at 800c, the
mats where mat and the glosses are not affected adversely. This is how I
fire my glaze kilns now.
These were my findings.
Regards from Alisa in Denmark
I found that the s
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