Jocelyn McAuley on tue 27 feb 01
Hi Bill,
Excellent list this is!
I recognized that you used David Snair's recipe... on my fifth reading of
your article. Is there any particular reason you only have nickel glazes
in your article? Oddly, nickel is one of the few colorants that didn't
really work in my base glaze (gave a mustard-green speckled background
with spidery thin blue crystals, less crystals as nickel increased).
I look forward to using your suggestion of 5%
lithium. We currently have end of term deadlines so I'll have to wait a
couple of weeks to do my testing.
--
Jocelyn McAuley ><<'> jocie@worlddomination.net
Jocelyn McAuley on tue 27 feb 01
Hello Fabienne,
> White bodies are recommended because of their being more responsive and
> "true" to the color you are trying to achieve. I use a c/6 porcelaneous
> body which is somewhat yellowish compared to the c/10 winter white buttery
> porcelains, as I call them. The same crystalline glaze that yields a
> yellow background with blue crystals on the c/10, gives me an muted
> greenish yellow with blue gray crystals on the yellowish c/6 porcelain. In
> a sense it's great; it expands our palette by just changing the "canvas." :)
I'm assuming that you don't fire the cone 6 clay to cone 9...
Is this the same cone ten formulated glaze that you fire to cone 6?
Did you use lithium carb to bring it down in temperature?
I'm curious about the color difference in taking a cone 10 crystalline
glaze down to cone 6. I just finished my 100 cone 9 tests for a class I
am taking. Now I wish I had worked on a lower temperature, as I probably
can't afford to do this sort of firing at home! I believe it was in the
Clay Times crystalline article that it was pointed out 5% LiCO3 brings the
cone 9/10 recipe down to cone 6.
I plan on playing with this soon, but wanted to know if anyone has
experience with this conversion, and the color changes that might result
in the recipe.
Thanks
--
Jocelyn McAuley ><<'> jocie@worlddomination.net
william schran on tue 27 feb 01
Jocelyn - I wrote the article in ClayTimes about crystalline glazes
at cone 6. I found one of David Snair's glazes from CM back in 1975
worked with addition of 5% lithium. I think the other formulas will
also work in the same manner. I'm playing with another frit from
General Color, #106, that's a cone 10 crystalline frit and working on
altering recipe for cone 6.
Bill
Fabienne Micheline Cassman on wed 28 feb 01
At 12:14 PM 02/27/2001 -0800, you wrote:
>Hello Fabienne,
>
>I'm assuming that you don't fire the cone 6 clay to cone 9...
Correct.
>Is this the same cone ten formulated glaze that you fire to cone 6?
Yes
>Did you use lithium carb to bring it down in temperature?
Not this one; I didn't have to which is why I picked it for
comparison. All that had changed was the clay body and the firing from c/9
to c/6.
>I'm curious about the color difference in taking a cone 10 crystalline
>glaze down to cone 6. I just finished my 100 cone 9 tests for a class I
So far, I have had no surprises in term of color changes by taking recipes
down to cone 6 with or without changing chemically. They are so close that
it doesn't bother me and I attribute it to the different clay body. I'm
sure eventually I'll stumble over mud, but one out of 10 is not bad even if
it is so.
>am taking. Now I wish I had worked on a lower temperature, as I probably
>can't afford to do this sort of firing at home! I believe it was in the
>Clay Times crystalline article that it was pointed out 5% LiCO3 brings the
>cone 9/10 recipe down to cone 6.
It's not writen in stone though; 5% is a good start, but may require
adjusting and more testing.
I also believe that by increasing the frit can do the same; however, I
haven't try that route yet.
Dan Turnidge is another source with came before the CT article; the MFE
glaze base was in there without a name tag. It appears that there may be
more people that work(ed) on c/6 crystalline than we know. Personally, I'm
sold out on them because it should lengthen the life of the kiln and
elements including my wallet and time :)
Which brings to mind. ZnO is very caustic and starts volatilizing at
c/08. Firing to c/6 would seem to give less time to it to corrode elements
or does it matter? Essentially, I am wondering if firing to c/6 would help
in that department as well. Anyone knows?
Cheers,
Fabienne
--
Milky Way Ceramics http://www.milkywayceramics.com/
Yes, I have learned from my mistakes...
I can reproduce them exactly.
Tom Buck on thu 1 mar 01
FMC:
I quarrel a bit with your statement that ZnO starts volatilizing
at 950 deg C (C08). You may be confusing Zn metal with Zinc Oxide. And
since you are firing in oxidative conditions there is no way that ZnO will
convert to Zn metal even at C6 (1230 C). ZnO starts to melt at 1975 C and
it would not have an appreciable vapour pressure (ie, give off vapours)
until it was molten. Hence, ZnO vapour will not migrate throughout the
kiln during the firing of pots covered in runny, high-ZnO crystalline
glazes.
be well. Peace. Tom.
Tom Buck ) tel: 905-389-2339
(westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
william schran on thu 1 mar 01
Jocelyn - The bowl on the cover of the mag has 6% copper carb. as the
colorant., another in the article also has copper.
Bill
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