ARTWORK by James Q. Jacobs

Cone 6 and 7 Glaze Formulas

Here are a few glaze formulas I have modified,
developed, or used at Mesa Community College.
Scroll down or use the links.

If you adjust the formulas, let me know about your changes and results.

Stony White -- cone 6-7 The first formulation was developed for spraying. When dipped the thicker areas fired rough in texture, with pitting. The second formulation was developed to resolve the texture problem, and has not been vigorously tested. Also, the quantity of red iron oxide in our studio batches was often mixed in the 0.3 to 0.5 percent range, instead of one percent. The pot on the left has a thin spray on the outside and tenmoku on the inside. The body is a studio pug clay with red iron oxide added.
	First formulation	Second formulation
nepheline syenite	340	26
silica / flint	250	28
whiting	130	17
kaolin	72	8
titanium oxide	60	6
lithium carbonate	36	4
zinc oxide	27	3
bentonite	18	2
tin oxide	18	2
zircopax	18	2
magnesium carbonate	1	1
red iron oxide	1	1

TOP

Bone Ash -- cone 7

G-200	390
Dolomite	300
EPK Kaolin	260
Bone Ash	50
Glaze sprayed over red iron oxide spray on white stoneware. Thick application is white, thinnest application is near the base. Richest brown areas have more iron spray. I reformulated this glaze for cone 7 firing.

More example pieces on Pottery V page.

This glaze is an attempt to create a high fire glaze that looks like burnished Puebloan earthenware. I do not recommend this formula for food ware.

Blue Hawaii -- cone 7
Blue Hawaii on porcelain. This glaze is very stable, and can be applied thick. Will blush lavender with good reduction at cone 7.
custer feldspar	340
silica	236
whiting	144
talc	32
bone ash	16
epk kaolin	8
gerstley borate	9
bentonite	8
copper carbonate	8
cobalt carbonate	4

Base recipe thanks to Judith Marks
Crater Rim Ceramics, Hawaii.

Majolica White - cone 6-7 The bottle on the right is coated with a thin spray of Majolica. The glaze was wiped off the design portion, to provide contrast, before a thin coat of glaze was added. Applied thick this is an opaque, white glaze. I find it to be particularly suitable for dinnerware, such as the insides of mugs. It also combines well with Noxema.		The clay used for the bottle is a studio pug blend with added iron. Speckling of several iron glazes also overlaid after spraying. To read about how the bas relief design was created go to the Pottery I page.
gerstley borate	300
custer feldspar	214
flint	180
zircopax	128
kaolin	111
dolomite	42
talc	25

TOP

Red Chun -- cone 6 Start your reduction at cone 04 and stay in reduction for the entire firing.
custer feldspar	428
silica	153
whiting	133
frit 3124	122
kaolin	51
zinc oxide	41
talc	31
tin oxide	21
bentonite	10
copper carbonate	10

Noxema Blue - cone 6 This bowl was thrown with Gary's white porcelain. The rim is double glazed. The interior is coated with a thin spray of Noxema Blue. The exterior has a thin spray coat of Stony White.
custer feldspar	483
wollastonite	232
kaolin	111
gerstley borate	101
flint	45
cobalt carbonate	28

Orange Carbon Trap Shino -- cone 7
nepheline syenite	160
soda ash	48
OM-4 ball clay	60
custer feldspar	48
epk kaolin	32
spodumene	36
red art clay	12
whiting	4
I have only tested this formula as a light spray, after adjusting the formula from cone 10. It looked good on small test tiles, but be careful.

If you test these formulas, I would be interested in your comments.
If you adjust the formulas, please send me any reformulations. Contact.