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

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

See Also:
Original G2571A cone 10R silky matte improved


Project Name

Cone 10R Silky Matte Hosting the Titanium/Color Mehchanism

Project Codenumber

UnAssigned

Notes

Dolomite matte glazes have long been a staple at cone 10R. However there are many that achieve the matte surface by not being adequately melted or by excessive surface crystallization. These are inferior, producing staining, cutlery marking and lack the pleasant silky surface. Many of these also have the issue of crazing.

For many years we have used the G2571A recipe. We calculated a recipe of similar chemistry using Ravenscrag Slip. And G2571A even inspired the development of a cone 6 equivalent, G2934Y.

However, this recipe does have room for improvement. While maintaining the chemistry we we should:
-Boron should be sourced from a frit rather than Gersley Borate (for reliability reasons).
-MgO should be sourced from talc instead of dolomite (to reduce the LOI).
-Kaolin should be reduced a little to avoid drying cracks.

These changes were made starting in G2571B. G2571C and G2571D showcase the stability of the matte effect and the potential it has to host the titanium/colorant mechanism (to produce rutile-like variegation). Even stains variegate with the titanium.

The red, blue and bamboo can all be improved (as noted for G2571B, C, D).
This titanium variegation effect will certainly work with other colors (stains preferred). We should test with orange, yellow, purple, green, etc.


Pictures

G2571B, C, D glazes on Plainsman H550, H443 tiles

Firing schedule is C10RPL

Original Cone 10R Silky Matte Base Recipe

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. It will not be a "matte white" unless Zircopax is added. Zircopax is also needed for other additions (e.g. rutile) for opacity. This recipe was improved at G2571B (talc instead of dolomite, more wollastonite, calcined kaolin, no silica).

There are many dolomite/whiting/feldspar/kaolin/silica glazes out there, but this one (add its successors) is better (mainly because it does not craze, cutlery mark or settle in the bucket). We calculated it from an original that sourced CaO from calcium carbonate (this employs dolomite and wollastonite instead).

We use this base as:

-a white (adding Zircopax or Superpax for opacity, e.g. 10%)
-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 G2571BB).
-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, with a specific gravity of 1.43-1.44, making it easy to apply.
-It has a low expansion which means it does not craze on any body we have tried.

Pictures

G2571A at cone 10 oxidation

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

G2571A base plus 5% manganese dioxide

BMix with G2571A bamboo and black engobe

This adds rutile and zircopax to the base. The upper part and insides had a black engobe applied at leather hard stage.

G2571A L4028 bamboo on P6589 H550

This adds rutile and zircopax to the matte white recipe. The upper part and inside had a brown engobe applied at leather hard stage.

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="Original Cone 10R Silky Matte Base Recipe" id="63980" key="9K4d6akF" date="2024-09-20" 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: 2024-09-20 17:31:03

G2571A Rutile Bamboo

Code #

L4028

Location

BD 840

P Materials Amt
Wollastonite 5.500
Custer Feldspar 28.500
EP Kaolin 28.000
Silica 15.000
Dolomite 19.000
Gerstley Borate 4.000
P Additions
* Ceramic Rutile 3.500
* Zircopax 10.000

Total:113.50

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

*We transplanted the rutile and zircopax addition into this base after seeing it in another glaze recipe. This base produced a more velvety surface with less tendency to stain. This glaze is worth mixing in a large bucket, we use alot of it.

To mix a batch we use the following proportions:
Glaze powder: 51.3%
Water 48.7%
5000 grams will produce a specific gravity of about 1.5 and volume of 7 litres.

Pictures

G2571A L4028 bamboo on P6589 H550

This adds rutile and zircopax to the matte white recipe. The upper part and inside had a brown engobe applied at leather hard stage.

L4028 bamboo on H550

L4028 vs. L4027 Bamboo

Both have the same rutile, zircopax addition.
The 4028 is based on G2571A, it is silkier. Likely more functional.
Body is H440.

L4028, 4027 bamboos very similar on H443

G2571A on H450 with L3954J black engobe

Fired at cone 10R. The black engobe has been applied inside and half way down the outsides.
Glaze on left is G2571A with 5% added rutile (Bamboo).
On the inside of the first mug is GR10-C Ravenscrag silky matte. The black engobe appears black under the clear glaze but brown under the bamboo glaze.

L4050B vase with G2571A bamboo

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="G2571A Rutile Bamboo" id="131711" key="2YbQ58Wz" date="2020-12-10" typecodes="ST" codenum="L4028" 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=""/> <recipeline material="Ceramic Rutile" amount="3.500" added="true"/> <recipeline material="Zircopax" amount="10.000" added="true"/> </recipelines> </recipe> </recipes>

Born: 2006-03-16, Modified: 2020-12-10 11:52:32

G2571B Rutile Bamboo

Code #

G2571BB

P 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
P Additions
* Rutile 3.500
* Zircopax 10.000

Total:113.50

Auto Unity Formula

CaO 0.52
MgO 0.34
K2O 0.10
Na2O 0.04
(KNaO) 0.14
B2O3 0.05
Al2O3 0.48
SiO2 2.66

Ratios

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

Expansion

6.6 (Molar:6.2)

LOI

3.7

Notes

*This adds rutile and zircopax to the G2571A base:

We are also using frit 3249, instead of Gerstley Borate, to source the B2O3 and some of the MgO. Use the L4028 recipe if you cannot get Frit 3249.

The fired result are visually the same as L4028 (the original bamboo base), but on close inspection that has a more silky and finer surface.

A darker color would be better, to get that add a little iron oxide, 1 or 2%.

Pictures

G2571B Bamboo on H550, H443 Cone 10R

G2571B Bamboo on H550 mugs

L3954N engobe is under it on the left mug.

Untitled

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="G2571B Rutile Bamboo" id="132632" key="HGpHcFvN" date="2024-09-20" typecodes="ST" codenum="G2571BB" 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="Rutile" amount="3.500" added="true"/> <recipeline material="Zircopax" amount="10.000" added="true"/> </recipelines> </recipe> </recipes>

Born: 2006-03-16, Modified: 2024-09-20 17:10:11

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="SZhM2hqP" 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

Cone 10R Silky Matte Red

Code #

G2571D

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 4.000
*Mason 6021 Red Stain 5.000

Total:109.00

Notes

*This adds the titanium and red stain to the new fritted base of G2571B. Fabulous results. However the amount of titanium is too little high, losing a bit of the silky feel of the surface. Next time try 3% and 3.5%.
The visual effect of this glaze is very striking. Also try more stain.

G2571D1 increases stain by 1, reduces titanium by 1.

Pictures

G2571D Matte Red on H570, H550 - Cone 10R

On H570 the surface has lost some of its silkiness, it feels more abrasive.

G2571D Matte Red on H570, H443 - Cone 10R

G2571D1, G2571D at cone 10 oxidation

On P600, H570
The D1 recipe has 1% less titanium and 1% more stain.

L4476 H570 mug cone 10ox firing

Glaze is G2571D1 and G3910A
Cone 10ox firing, drop and hold firing but not slow cool.
G3910A crazed over time.

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 Red" id="185876" key="xEvEFt7K" date="2022-03-17" typecodes="ST" codenum="G2571D" 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" amount="4.000" added="true"/> <recipeline material="Mason 6021 Red Stain" amount="5.000" added="true"/> </recipelines> </recipe> </recipes>

Born: 2006-03-16, Modified: 2022-03-17 20:42:57

Cone 10R Silky Matte Black

Code #

G2571E

Materials Amt
Wollastonite 21.000
Custer Feldspar 32.000
EP Kaolin 20.000
Calcined Kaolin 9.000
Talc 14.000
Fusion Frit F-69 4.000
Additions
*Mason 6600 Black 6.000

Total:106.00

Notes

*This is a followup to G3908, which used 6666 stain (it fired dark brown).

Pictures

G2571E silky matte black at cone 10R

Reduction was a light heavier than normal.

G2571E silky matte black mug at cone 10R

Reduction was a light heavier than normal.

G2571E at cone 10 oxidation

It has turned glossy!

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 Black" id="205485" key="7TidDwKi" date="2022-01-06" typecodes="ST" codenum="G2571E" 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="Fusion Frit F-69" amount="4.000" tolerance=""/> <recipeline material="Mason 6600 Black" amount="6.000" added="true"/> </recipelines> </recipe> </recipes>

Born: 2006-03-16, Modified: 2022-01-06 14:21:45