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
|
Si:Al: 5.6:1 6.7 (Molar:6.3) 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="bdkjkh4E" 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 | |
|---|---|---|
| * | Ceramic Rutile | 3.500 |
| * | Zircopax | 10.000 |
Total:113.50
Auto Unity Formula
|
Si:Al: 5.6:1 6.7 (Molar:6.3) 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.
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="SrnDLCxi" 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 | |
|---|---|---|
| * | Rutile | 3.500 |
| * | Zircopax | 10.000 |
Total:113.50
Auto Unity Formula
|
Si:Al: 5.5:1 6.6 (Molar:6.2) 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.
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="Cone 10R Silky Matte Bamboo 2" id="132632" key="YfkJ91Df" date="2022-11-18" 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: 2022-11-18 14:57:46
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
|
Si:Al: 5.5:1 6.9 (Molar:6.4) 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="xYK14R3i" 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="R5ZhBfLp" 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="RQPsc5YD" 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
