Seeking a cone 6 white glaze recipe for very dark clay body

[Natania 6]

I am using a very (very) dark clay body that fires to almost black, and would Iike to find a white glaze that stays mostly white on it, and does not look like, well, like snot (as most of the ones I've tried so far do). Preferably glossy or satin. Unfortunately, I don't know what exactly colors the clay, but I assume plenty of iron oxide... Perhaps some manganese too? I could check with the manufacturer I suppose, but the clay is so dark that most light glazes do horrible things when fired on it...any suggestions?

[bciskepottery 959]

What cone? 04? 6? 10? Oxidation or reduction?

[weeble 5]

The best results I've seen (cone 5 clays, Lagunas 'Brown' and forget who makes it 'Cassius Clay') were when a layer of compatible white slip was applied under the glaze. Otherwise, I tell students they're probably going to get mud-colored glazes, because, well, they always seem to. The clay really messes with the glaze.

[Marcia Selsor 1,781]

This will work in Oxidation for the white. The other colorants will not be as described for reduction. This glaze came from a shared handout from the 1970s .

 

Marcia

 

 

White Liner ^6 Reduction

 

Ger. Borate 20

 

Neph. Syenite 30

 

Kaolin 13.3

 

Whiting 9.4

 

Talc 17.2

 

Silica 10

 

Zircopax 10

 

 

ADD :Pumpkin 5% Red Iron + 3% Rutile

 

Gold 3% Rutile

 

Lt. Blue 0.5% Cobalt Carb

 

 

 

 

[bciskepottery 959]

This breaks nicely on Standard 266 dark brown:

 

Antique White ^6

 

Neph Syenite 41.7

Silica 16.7

Gerstley Borate 25.0

EPK kaolin 8.3

Whiting 8.3

Total 100.0

 

Bentonite 2.2

Tin Oxide 8.3

Red Iron Oxide 0.9

 

(Sorry about asking cone in earlier post; senior moment)

[Natania 6]

Oops. Sorry - cone 6. I have tried some white slips, but they didn't fit the clay body very well. I haven't really explored a lot of slip recipes though. I've seen a few examples of something called nuka-type glaze on dark clay. Does anyone know what that means? I will try the above white glaze recipes ASAP - thank you!