Original G2571A cone 10R silky matte improved

Original Cone 10R Silky Matte Base Recipe

Total:100.00

Auto Unity Formula

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.

Cone 10R Silky Matte Base (improved)

Total:99.00

Auto Unity Formula

Notes

*This improves the G2571A base as follows:
-It sources MgO from talc (instead of dolomite). This change drops the LOI dramatically (less chance of blisters and pinholes).
-It eliminates the silica (which is pure quartz) from the recipe (the talc and wollastonite supply the SiO2), so this is safer to use!
-This employs a combination of calcined and raw kaolin (the 28% kaolin in the original G2571A is a lot and causes high shrinkage as the glaze dries, that could mean cracking and crawling). This mix of raw and calcined kaolin enables trading them one-for-another to optimize performance (more calcined means less shrinkage but less dry hardness, more raw kaolin makes a better slurry that dries harder but is more likely to crack).

This version can be made more matte (although care is needed to avoid cutlery marking) by reducing or eliminating the Gillespie Borate.
It can be made more glossy by adding silica (likely only a small percentage is needed).

Mahavir Feldspar would also work. The thermal expansion is low enough that even a soda feldspar should be fine. If degree of gloss is affect see above paragraph.

If you cannot get Wollastonite, then use the original G2571A recipe - but it would be good to follow the pattern of this recipe version by splitting the 28% kaolin into 20:9 (9 parts instead of 8 because of the 10-12% LOI of kaolin).

Pictures

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 Base (improved)" id="252375" key="DXYMFGrz" date="2024-09-20" typecodes="ST" codenum="G2571B" picturebasename=""> <recipelines> <recipeline material="Wollastonite" amount="19.000" tolerance=""/> <recipeline material="Custer Feldspar" amount="32.000" tolerance=""/> <recipeline material="EPK" amount="20.000" tolerance=""/> <recipeline material="Calcined Kaolin" amount="9.000" tolerance=""/> <recipeline material="Talc" amount="14.000" tolerance=""/> <recipeline material="Gillespie Borate" amount="5.000" tolerance=""/> </recipelines> </recipe> </recipes>

Born: 2006-03-16, Modified: 2024-09-20 17:30:53

G2571A Rutile Bamboo

Total:113.50

Auto Unity Formula

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

G2571B Rutile Bamboo

Total:113.50

Auto Unity Formula

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.

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