Original G2571A cone 10R silky matte (slightly improved)

Share from Insight-live.com (Lab Documentation and Calculation System) by Digitalfire. https://digitalfire.com

See Also:
Develop a Range of Colors for the G2571A Silky Matte Cone 10R Base

We reformulated this to replace the feldspar and use wollastonite instead of calcium carbonate (while maintaining the chemistry). The new version became the base to which we add many colorants and variegated.


Cone 10R Silky Matte White Base Glaze

Code #

G2571A

Location

BD 840

Materials Amt
Wollastonite 5.500
Custer Feldspar 28.500
EP Kaolin 28.000
Silica 15.000
Dolomite 19.000
Gerstley Borate 4.000

Total:100.00

Auto Unity Formula

CaO 0.52
MgO 0.33
K2O 0.10
Na2O 0.05
(KNaO) 0.15
B2O3 0.05
Al2O3 0.47
SiO2 2.62

Ratios

Si:Al: 5.6:1
SiB:Al: 5.7:1
R2O:RO: 0.1:0.9

Expansion

6.7 (Molar:6.3)

LOI

14.5

Notes

*This is a silky matte with a very nice texture to the touch.
There are many dolomite/whiting/feldspar/kaolin/silica glazes out there, but this one is the best. We calculated it from an original that sourced CaO from calcium carbonate (this employs wollastonite instead).

We use this base as:

-a white (adding superpax for extra opacity if needed)
-a powder blue using 1% cobalt oxide and .2% chrome oxide
-an oatmeal using 3-5 manganese for a tan to brown (manganese does flux it a bit so kaolin could be added). Note that we found a rutile/zircopax addition was better, see G2571B).
-copper for a pink silky

7000 grams makes about 2.5 gallons.

This glaze also works well at cone 10 oxidation (slow cool the kiln if defects occur).

In heavy reduction it does not work nearly as well with some colorants, tending toward a drier much less silky surface.

This base has several strong points:

-It works well on porcelains, even using the managanese addition.
-It works well on stonewares and iron stonewares.
-It has extremely good thixotropic properties making it easy to apply.
-It has a low expansion which means it does not craze on most bodies.

Pictures

Cone 10 Oxidation.\nWhite: 4% tin\n

Cone 10 Oxidation.\nWhite: 4% tin\nBlue: 4% tin, 4% 6226 stain\nPink: 4% tin, 5% Cerdec 279497 Red

With 5% manganese dioxide.

With 5% manganese dioxide.

Typecodes

ST-Untitled typecode

Alternate Code Number:GS10-G

XML (to paste into Insight)

<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Cone 10R Silky Matte White Base Glaze" id="63980" key="9e8R2Cjw" date="2020-12-10" typecodes="ST" codenum="G2571A" location="BD 840" picturebasename=""> <recipelines> <recipeline material="Wollastonite" amount="5.500" tolerance=""/> <recipeline material="Custer Feldspar" amount="28.500" tolerance=""/> <recipeline material="EP Kaolin" amount="28.000" tolerance=""/> <recipeline material="Silica" amount="15.000" tolerance=""/> <recipeline material="Dolomite" amount="19.000" tolerance=""/> <recipeline material="Gerstley Borate" amount="4.000" tolerance=""/> </recipelines> </recipe> </recipes>

Born: 2006-03-16, Modified: 2020-12-10 11:54:44

Cone 10R Powder Blue Silky

Code #

G2571F

Location

BD 831

Materials Amt
Whiting 4.000 3.94%
G200 Feldspar 29.000 28.57%
EPK 25.500 25.12%
Silica 18.500 18.23%
Dolomite 19.000 18.72%
Gerstley Borate 4.000 3.94%
Chrome Oxide 0.250 0.25%
Cobalt Oxide 1.000 0.99%
*Manganese Granular 0.250 0.25%

Total:101.50

Auto Unity Formula

CaO 0.49
MgO 0.32
K2O 0.10
Na2O 0.05
(KNaO) 0.15
B2O3 0.05
Al2O3 0.44
SiO2 2.49
CoO 0.04

Ratios

Si:Al: 5.7:1
SiB:Al: 5.8:1
R2O:RO: 0.2:0.8

Expansion

6.7 (Molar:6.3)

LOI

15.6

Cost

0.76 per kg

Notes

*This is the original version (see G2571A for a wollastonite version used today). For a titanium/colbalt version of this, see G2571C.

On light bodies this fires powder blue to a more glossy crystal blue depending on thickness and firing. If used on an iron body it is a much darker matte to turquoise. Produces quite striking subtle colors and surface textures when used as a second layer over tenmoku.

Pictures

G2571 Cone 10R Powder Blue Silky pitcher - Tony

G2571F on H550

Over black engobe on upper half.

Typecodes

ST-Untitled typecode

XML (to paste into Insight)

<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Cone 10R Powder Blue Silky" id="63979" key="6rQe12Ef" date="2021-11-04" typecodes="ST" codenum="G2571F" location="BD 831" picturebasename=""> <recipelines> <recipeline material="Whiting" amount="4.000" tolerance=""/> <recipeline material="G200 Feldspar" amount="29.000" tolerance=""/> <recipeline material="EPK" amount="25.500" tolerance=""/> <recipeline material="Silica" amount="18.500" tolerance=""/> <recipeline material="Dolomite" amount="19.000" tolerance=""/> <recipeline material="Gerstley Borate" amount="4.000" tolerance=""/> <recipeline material="Chrome Oxide" amount="0.250" tolerance=""/> <recipeline material="Cobalt Oxide" amount="1.000" tolerance=""/> <recipeline material="Manganese Granular" amount="0.250" tolerance=""/> </recipelines> </recipe> </recipes>

Born: 1994-07-15, Modified: 2021-11-04 17:36:14

Cone 10R Silky Matte Blue

Code #

G2571C

Materials Amt
Wollastonite 21.000
Custer Feldspar 32.000
EP Kaolin 20.000
Calcined Kaolin 9.000
Talc 14.000
Ferro Frit 3249 4.000
Additions
Titanium Dioxide 4.000
Cobalt Oxide 0.500

Total:104.50

Auto Unity Formula + Analysis

CaO 0.51 9.97%
MgO 0.34 4.76%
K2O 0.09 3.13%
Na2O 0.04 0.93%
(KNaO) 0.14
TiO2 0.14 3.90%
P2O5 0.00 0.05%
B2O3 0.05 1.11%
Al2O3 0.47 16.83%
SiO2 2.61 54.93%
CoO 0.02 0.45%
Fe2O3 0.00 0.18%

Ratios

Si:Al: 5.5:1
SiB:Al: 5.6:1
R2O:RO: 0.1:0.9

Expansion

6.9 (Molar:6.4)

LOI

3.8

Notes

*G2571A has been our go-to dolomite matte base for many years. It has very low thermal expansion, by virtue of low levels of KNaO, and fits bodies very well. And it thrives on colorant and variegator additions. So it seemed a natural to make our rutile blue using this.

This adds the titanium and cobalt to the new fritted base version of G2571A: G2571B. Titanium is being used to get better blue, rutile supplies TiO2 like titanium, but also brings along iron that muddies blue coloration.

Fabulous results. The variegation is excellent.

More cobalt would be better on white stonewares, perhaps 0.75%.

Pictures

G2571C on a buff stoneware at cone 10R

G2571C blue crystal matte on H443, H550 Cone 10R

G2571C blue crystal matte on H570, Polar Ice cone 10R

Cone 10R G2571C Blue rutile dolomite matte

Typecodes

ST-Untitled typecode

Alternate Code Number:GS10-G

XML (to paste into Insight)

<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Cone 10R Silky Matte Blue" id="185875" key="F842ia1e" date="2022-02-26" typecodes="ST" codenum="G2571C" picturebasename=""> <recipelines> <recipeline material="Wollastonite" amount="21.000" tolerance=""/> <recipeline material="Custer Feldspar" amount="32.000" tolerance=""/> <recipeline material="EP Kaolin" amount="20.000" tolerance=""/> <recipeline material="Calcined Kaolin" amount="9.000" tolerance=""/> <recipeline material="Talc" amount="14.000" tolerance=""/> <recipeline material="Ferro Frit 3249" amount="4.000" tolerance=""/> <recipeline material="Titanium Dioxide" amount="4.000" added="true"/> <recipeline material="Cobalt Oxide" amount="0.500" added="true"/> </recipelines> </recipe> </recipes>

Born: 2006-03-16, Modified: 2022-02-26 18:38:54