Develop a Range of Colors for the Titanium/Stain Variegation Mechanism at cone 10R

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


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

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.\nBright blue.

Cone 10 oxidation.\nBright blue.

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="u4D3fxez" 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

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 Amt
* 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

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.

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="2LnoFgtd" 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

Cone 10R Silky Matte Bamboo 2

Code #

G2571B

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 Amt
* 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 alters the G2571A base as follows:
-It sources CaO and MgO from wollastonite, talc and frit (instead of dolomite and talc). This change drops the LOI dramatically and eliminates even the silica from the recipe (the talc and wollastonite supply the SiO2)!
-This employs a combination of calcined and raw kaolin, that enables trading them one-for-another to fine-tune the slurry and drying properties.
-The frit 3249 sources B2O3 (enabling dropping the Gerstley Borate) and MgO (in a much more readily meltable form).

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, for the next test add a little iron oxide, 1 and 2%.

Pictures

G2571B Bamboo on H550, H443 Cone 10R

G2571B Bamboo on H550 mugs

L3954N engobe is under it on the left mug.

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 Bamboo 2" id="132632" key="CMY61Hi4" date="2020-12-24" typecodes="ST" codenum="G2571B" 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: 2020-12-24 13:56:04

Cone 10R Silky Matte Blue

Code #

G2571C

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 Amt
* Titanium 4.000
* Cobalt Oxide 0.500

Total:104.50

Auto Unity Formula + Analysis

CaO 0.52 10.44%
MgO 0.34 4.98%
K2O 0.10 3.27%
Na2O 0.04 0.97%
(KNaO) 0.14
TiO2 0.00 0.07%
P2O5 0.00 0.05%
B2O3 0.05 1.16%
Al2O3 0.48 17.62%
SiO2 2.66 57.51%
Fe2O3 0.00 0.19%

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 the titanium and cobalt to the new fritted base of G2571B. Fabulous results. The variegation produced by the titanium is OK (whereas the same amount with the red stain is excessive).

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

Pictures

G2571C blue crystal matte on H443, H550 Cone 10R

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

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="cNexxNCD" date="2020-12-24" 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" amount="4.000" added="true"/> <recipeline material="Cobalt Oxide" amount="0.500" added="true"/> </recipelines> </recipe> </recipes>

Born: 2006-03-16, Modified: 2020-12-24 13:55:11

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 Amt
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.

Pictures

G2571D Matte Red on H443, H550 Cone 10R

G2571D Matte Red on H570, H550

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

G2571D Matte Red on H570, H443

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="NbkEG5NS" date="2021-08-31" 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: 2021-08-31 11:59:56