Ron Roy on tue 17 feb 98
These comments and glaze were posted while I was away and I though they
deseved some comment.
At cone 10, the limit formulas I use tell me it is short of silica and
therefore durability is suspect. On the other hand there are no problematic
oxides present so it should not be a hazard. I might become dull (etched)
with time and use however.
At cone 6 it does have enough silica - it does have some extra CaO but not
enough to affect the durability much.
My point is - it's a better glaze at cone 6 than at cone 10.
It will craze on just about any body.
Lasse Ostman has a few glaze recipes on her website. One of these is S422
Semi matt golden yellow. She fires this to 1270 C with a one hour soak. It
is described as a very intensive golden yellow. I fire to a very full cone
6. I have never paid much attention to what cone a glaze is supposed to go
to (as long as it is from 5-10) and as a result have a few very nice glazes
that are being underfired. At cone 6 oxidation, this glaze is an
interesting pale yellow cream that pools and just has a very interesting
surface. I just tried it on a vertical test tile (usually I do most work
flat) and it was more in the tan range (just a little). But it was
impressive and would be worth a test on a small bowl. A very elegant glaze.
Here is the recipe:
Potash feldspar 64.35
whiting 18.93
epk 3.15
albany slip 5.68 (I used Miller's/Laguna's albany
substitute)
rutile 7.89 (I used the 325 mesh light
that US Pigment sells)
FeO spanish 6.31
It works fine single fired.
Ron Roy
93 Pegasus trail
Scarborough Otario
Canada M1G 3N8
Phone: 416-439-2621
Fax: 416-438-7849
Web page: Home page http://digitalfire.com/education/people/ronroy.htm
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