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berry rust

updated wed 20 jan 99

 

LINDA BLOSSOM on tue 22 oct 96

Some time ago someone posted a recipe for a glaze named Berry Rust. I
copied it on a small notepad, tore it out and took it to the studio.
Finally, I tried it and liked it. The day after I fired, the little
notebook page, which had traveled all over the studio and come out alive,
was gone. Not a trace. Any memory of this glaze - anyone? Sorry for the
trouble and thanks.

Linda Blossom
2366 Slaterville Rd.
Ithaca, NY 14850
blossom@lightlink.com
http://www.artscape.com
607-539-7912

Sam Cuttell on tue 22 oct 96

At 09:09 AM 10/22/96 EDT, you wrote:
>----------------------------Original message----------------------------
>Some time ago someone posted a recipe for a glaze named Berry Rust. I
>copied it on a small notepad, tore it out and took it to the studio.
>Finally, I tried it and liked it. The day after I fired, the little
>notebook page, which had traveled all over the studio and come out alive,
>was gone. Not a trace. Any memory of this glaze - anyone? Sorry for the
>trouble and thanks.
>
>Linda Blossom
>2366 Slaterville Rd.
>Ithaca, NY 14850
>blossom@lightlink.com
>http://www.artscape.com
>607-539-7912
>
I believe the recipe is from Jean Lehman. Try contacting her.

sam - alias the cat lady
Home of Manx cats, Cavalier King Charles Spaniels and the odd horse
Melbourne, Ontario, CANADA
(SW Ontario)
http://www.geocities.com/paris/3110

John Post on tue 22 oct 96

This may be the glaze you're looking for.
I found it on the SDSU ceramics web.

Glaze name: Berryrust
Cone: 7 - 10
Color: cranberry rust red
Testing: Untested
Surface texture:
Firing: Ox. or Red.
Glaze type:

Recipe: Percent Batch
Silica 27.27 136.4
EPK 18.18 90.9
Nepheline Syenite 18.18 90.9
Dolomite 9.09 45.5
Gerstley Borate 9.09 45.5
Talc 9.09 45.5
Bone Ash 9.09 45.5
Totals: 100.00 % 500.0 Gm

Also add:
Red Iron Oxide 9.09 45.5

Comments:
> ClayArt Listserv recipe <
If you find this glaze useful, please consider submitting it to the
GlazeBase project with full documentation. Use one of the GlazeBase
submission formats available on the CeramicsWeb web page.

comments: Use Pure Red Iron Oxide .
This glaze gives a fairly intense cranberry rust in the cone 7-10 range and
is quite consistent in its results. Every once in a while, when the glaze is
thicker than normal, a pale but distinctive green (a little like a pale
chrome green) begins to float on the surface. Any suggestions as to why? In
addition, in reference to an earlier note about the changing reds over time,
I think this red becomes somewhat brighter (and more red) the older the
glaze is. I don't yet use a lot of it so it sits for quite a while
(3-5 months).
submitted by: Bob Kavanagh
e-mail: bkav@VAX2.CONCORDIA.CA

Possible Health Hazards:
Silica: free silica-wear a NIOSH approved dust mask when handling dry material
Talc: wear a NIOSH approved dust mask when handling dry material


Unity Formula for Berryrust:
0.028 K2O 0.309 Al2O3 2.475 SiO2
0.104 Na2O 0.107 B2O3 0.003 TiO2
0.528 CaO 0.003 Fe2O3 8.0:1 Si:Al Ratio
0.340 MgO 0.081 P2O5

Percentage Analysis:
58.93 % SiO2
12.49 % Al2O3
2.93 % B2O3
1.03 % K2O
2.54 % Na2O
11.74 % CaO
5.43 % MgO
0.20 % Fe2O3
4.56 % P2O5
0.08 % TiO2

>----------------------------Original message----------------------------
>Some time ago someone posted a recipe for a glaze named Berry Rust. I
>copied it on a small notepad, tore it out and took it to the studio.
>Finally, I tried it and liked it. The day after I fired, the little
>notebook page, which had traveled all over the studio and come out alive,
>was gone. Not a trace. Any memory of this glaze - anyone? Sorry for the
>trouble and thanks.
>
>Linda Blossom
>2366 Slaterville Rd.
>Ithaca, NY 14850
>blossom@lightlink.com
>http://www.artscape.com
>607-539-7912
>

carrie or peter jacobson on sat 16 jan 99

An observation and question for you experts:

A while ago, I mixed and tested this glaze:

++++++++++++++++++++++
+++ Berry Rust +++
++++++++++++++++++++++

Range: 7-10 (It is fine at 6 also)
Firing type: Oxidation
Color: Red
Source: Bob Kavanaugh, Clayart
Date: 12/31/97

Flint 27.3%
EPK 18.2%
Nepheline syenite 18.2%
Dolomite 9.1%
Gerstley borate 9.1%
Talc 9.1%
Bone ash 9.1%
------
100 %

Red iron oxide 9.1%


+++++++++++++++++

The results were not that spectacular on porcelain (way more brown than red
or rust) but were more interesting on red stoneware. So I mixed up a batch.

One of the students put too much on something and it dripped onto the kiln
shelf. I didn't bother to scrape it off, it was before Christmas, I had
more important things to do.

This week, I bisqued a load to 05, and when I unloaded the kiln last night,
I noticed that the berry rust drip had changed: Instead of a brownish red
with greeny-brown speckles, it was now a much, much brighter red, still
rich and deep, but more like the color of blood, the color of a Vermont
barn in winter, a nice red.

Does anyone understand what has happened here?

Thanks!

Carrie













Carrie Jacobson
Pawcatuck, CT
mailto:jacobson@brainiac.com

Chris Schafale on sun 17 jan 99

Hi Carrie,

Me again. The explanation I have read of this phenomenon is that
refiring to bisque temps gives the iron red glaze an extra couple of
hours in the crucial temperature range where the iron crystals form
(the iron crystals are what cause the red color). Apparently both
the heating and the cooling parts of the re-firing cycle can
encourage this process to continue, if it was started off during the
original firing. I think there's a chart in Hamer that shows this
(no, I'm not sure in what article, maybe the one on crystallization?)
I've read that some people do this routinely with the iron reds to
get better colors. It didn't work all that dramatically for me,
unfortunately, but maybe the crystallization hadn't really gotten
going enough in the first firing.

Chris

> ----------------------------Original message----------------------------
> An observation and question for you experts:
>
> A while ago, I mixed and tested this glaze:
>
> ++++++++++++++++++++++
> +++ Berry Rust +++
> ++++++++++++++++++++++
>
> Range: 7-10 (It is fine at 6 also)
> Firing type: Oxidation
> Color: Red
> Source: Bob Kavanaugh, Clayart
> Date: 12/31/97
>
> Flint 27.3%
> EPK 18.2%
> Nepheline syenite 18.2%
> Dolomite 9.1%
> Gerstley borate 9.1%
> Talc 9.1%
> Bone ash 9.1%
> ------
> 100 %
>
> Red iron oxide 9.1%
>
>
> +++++++++++++++++
>
> The results were not that spectacular on porcelain (way more brown than red
> or rust) but were more interesting on red stoneware. So I mixed up a batch.
>
> One of the students put too much on something and it dripped onto the kiln
> shelf. I didn't bother to scrape it off, it was before Christmas, I had
> more important things to do.
>
> This week, I bisqued a load to 05, and when I unloaded the kiln last night,
> I noticed that the berry rust drip had changed: Instead of a brownish red
> with greeny-brown speckles, it was now a much, much brighter red, still
> rich and deep, but more like the color of blood, the color of a Vermont
> barn in winter, a nice red.
>
> Does anyone understand what has happened here?
>
> Thanks!
>
> Carrie
>
>
>
>
>
>
>
>
>
>
>
>
>
> Carrie Jacobson
> Pawcatuck, CT
> mailto:jacobson@brainiac.com
>
>
Light One Candle Pottery
Fuquay-Varina, NC
candle@nuteknet.com

Lili Krakowski on tue 19 jan 99

Actually I do not know what happened. But I do know that many years ago
Hobart Cowles at School for American Craftsmen developed a bunch of Albany
Slip glazes that were fired to c.5 or 6 and re-fired at c.o4 for a
brighter red. I published some of these in CM I think in 1983 or 1984
under ALbany Slip glazes--check them out. If you send me your snail maila
ddress directly I probably can locate (I am not at home) and mail.

Lili Krakowski

cyberscape on tue 19 jan 99

Carrie, what happened is that the bisquit firing oxidized your iron red.
If you oxidize at the end of cone 10 firing, often the glazes are richer
and brighter, even the ones requiring reduction, and especially the iron
reds. After a good hard reduction, I have always cleaned up in
oxidation for half an hour before turning the kiln off. Same routine
for everything else except copper reds.

Harvey Sadow