Daniel Semler on sun 21 aug 05
Hi Vince, All,
I got the tests back for this. Looks good. Could be tweaked a bit, but then
what glaze couldn't :) Its certainly pretty close. I'd say that may be less
SrCO3 could be used than BaCO3 as I think that the SrCO3 version as I did it is
a little drier.
Full write up is on http://localhost/~dsemler/Clayosmos/clayart.html. Sorry
for the time to load on this page. I'll fix it to be multiple pages for all the
Clayart stuff when I get a minute.
Thanx
D
Daniel Semler on sun 21 aug 05
Hi All,
Sorry about the URL. That's my local test site. The real one is
http://www.clayosmos.com/clayart.html.
Sorry - can I claim jet lag ?
D
> Hi Vince, All,
>
> I got the tests back for this. Looks good. Could be tweaked a bit, but then
> what glaze couldn't :) Its certainly pretty close. I'd say that may be less
> SrCO3 could be used than BaCO3 as I think that the SrCO3 version as I
> did it is
> a little drier.
>
> Full write up is on http://localhost/~dsemler/Clayosmos/clayart.html. Sorry
> for the time to load on this page. I'll fix it to be multiple pages
> for all the
> Clayart stuff when I get a minute.
>
> Thanx
> D
>
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Maurice Weitman on sun 21 aug 05
At 1:38 AM -0400 on 8/21/05, daniel@clayosmos.com wrote:
>[...]
> Full write up is on http://localhost/~dsemler/Clayosmos/clayart.html.
Hi, Daniel and all you claybuds out there...
I'd say that Daniel meant to give
as the URL for his cool test results.
He probably got a bit Woo-zy and forgot that we all weren't on his network.
Regards,
Maurice, back home in Fairfax, California, where summer is waning.
Still sunny, nearly warm, but fall's crispness is in the air. Most
of the Robins that sang to us earlier this summer are gone, and most
of the rest of the other birds' broods have fledged, although we did
see some Acorn Woodpeckers feeding tiny mouths yesterday around the
lake.
We had a great summer, with a road trip north to Oregon, and a silver
bird trip to the right coast to visit family. It was a kick to throw
my grandkids around in my son's pool in NJ, to see Mmle. Forer,
however briefly, visit with my brothers in RI, and other family and
friends in NY and NE. And it's great to be home where my studio's
dying to be muddied, and I am eager to comply.
Vince Pitelka on mon 22 aug 05
> Sorry about the URL. That's my local test site. The real one is
> http://www.clayosmos.com/clayart.html.
Daniel -
Thanks for testing this substitution. How accurate are the colors on those
test tiles as they appear online? How bright was the yellow? We get a very
bright yellow from our Woo Yellow with barium carbonate. I'd hate to
compromise that.
As I remember, when replacing barium carbonate with strontium carbonate, it
takes 75% as much strontium. Is that the substitution that you used?
Thanks -
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Daniel Semler on mon 22 aug 05
Hi Vince,
Alas, colours and machines ! Its hard to be sure that what you're seeing is
what I'm seeing. Macs, PCs differ, the camera and so on also. I suspect it
looks darker on a PC, I find images often do. On my Mac the match is not bad,
but without seeing your Woo Yellow and mine side by side it would be hard to
tell for sure. The yellow is fairly bright in both barium and strontium. Not a
lemon yellow, rather more mustard yellow, though not Keens, if that makes
sense. The strontium one is a little more orangey but only a bit. The
yellow is
stronger where its thin on porcelain and where its thicker on the
stoneware, in
redux.
As to the way I came up with the sub. What I did was to sub the same molar
equivalent amount of SrO for BaO. This of course resulted in a couple of small
tweaks to the other components to maintain the other flux oxides in the same
relative proportions. That said the amount I used is about 78% of the barium
carb used in the original. This seemed the best way to see the effect of just
subbing BaO for SrO in the fired glaze.
I might try a blend using differing amounts of strontium carb and see what
happens. As I noted on the web page, I think the glaze is slightly drier,
perhaps too much SrO. Need to work out if SrO is more or less refractory than
BaO.
If I can get this tweaked a little then you can try it there and see how it
looks.
A couple of questions for you :
1. is this normally fired in reduction or oxidation ?
2. is it normally used on medium to dark stoneware bodies, or on whiter
stonewares and porcelains ?
3. do you normally apply it thickly, thinly etc ?
These bits of info will help me with the next round of tests.
Thanx
D
Vince Pitelka on tue 23 aug 05
> 1. is this normally fired in reduction or oxidation ?
> 2. is it normally used on medium to dark stoneware bodies, or on whiter
> stonewares and porcelains ?
> 3. do you normally apply it thickly, thinly etc ?
Daniel -
We always fire our Woo yellow in reduction, and sometimes in salt or soda,
both of which can give very nice results. I like it best on a light
stoneware body in all three firing processes. I try to avoid putting it on
too thick, because then it gives more of a fat mustard yellow. Where it is
very thin it goes to brown on a stoneware body, and to buff on a porcelain
body.
Thanks for doing and publishing these tests.
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
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