greenwich house pottery clay and glaze

7/30/2019 Greenwich House Pottery Clay and Glaze

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Greenwich House Pottery16 Jones Street, New York, New York 10014

p: 212-242-4106 f: 212-645-5486 e: [email protected] us online: greenwichhousepottery.org

facebook.com/greenwichhousepotterytwitter.com/ghpottery

Est. 1909

School Year 2010-2011

Greenwich House Pottery (GHP) is one of the oldest non-profits in the countrdedicated solely to the inquiry and advancement of the ceramic arts. GHP has bee

educating and introducing New Yorkers to clay since 1909. Over the past 100-years ihas become an internationally recognized center for ceramics - offering a diversprogram of classes for adults and children Solo, Group and Juried Exhibitions

Artist-in-Residence program Lecture Series Summer Masters Series workshopsand Community Outreach, all of which serve newcomers, amateurs, and professionartists alike.

With one of the largest ceramics faculty of any ceramic educational facility, GHP hasomething for everyone. Many important figures have taught, lectured, exhibited, otaken classes within these walls such as Rudy Autio, Ruth Duckworth, Shoji HamadTony Hepburn, Margaret Isreal, Jun Kaneko, Bernard Leach, David Leach, JohLeach, Warren MacKenzie, Louise Nevelson, Don Reitz, Byron Temple, RoberTurner, and Peter Voulkos, to name a few. In 2009, New York City Mayor MichaeBloomberg awarded GHP a Mayoral Proclamation and declared September 10th, 200

Greenwich House Pottery Day.

Extending our educational mission, GHP, maintains an ongoing exhibition series. ThJane Hartsook Gallery and The Pottery Shop at GHP are committed to supportin

both emerging and established ceramic artists, and to the educational mission omaking, exhibiting, and learning from contemporary ceramics.

About Greenwich House, Inc.Greenwich House Pottery is a program of Greenwich House Inc., a settlement housfounded in 1902 by Mary Kingsbury Simkhovitch. Located at 27 Barrow StreeGreenwich House offers a wide array of programs designed to enrich the lives of Ne

Yorkers, including the Barrow Street Nursery School, Music School (46 BarroStreet), Substance Abuse, Childrens Safety Project, Judith C. White Senior CenteSenior Health & Consultation, and health care and services for people living witHIV/AIDS.

Our programming is made possible by the generosity of foundations, corporatsponsorship, and through individual charitable gifts by people like you.

Welcome to GHP, and thank you for your continued support.

Cover: Woodblock Print by Peter Gourfain, 2010 (Altered)Back: First GHP Brochure 1948-1949 Jane Hartsook, 1948


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OUR FACILITIESWe offer 35 Adult classes, a Childrens class at 27 Barrow Street, 2 Parent & Childclasses, a homeschool class, Summer Master Classes, and Summer Camp for childrenand teens. Day and evening classes are scheduled Monday through Saturday. Ourstudios are equipped with 2 handbuilding classrooms, 2 throwing classrooms, 28potters wheels, 2 up-draft gas kilns, 4 Skutt computerized electric kilns, a slab roller, 2Soldner clay mixers, one Peter Pug mill, 2 clay extruders, and a spray booth. We offer5 clay bodies: white stoneware, throwing stoneware, sculpture stoneware, redearthenware, and we sell grolleg porcelain for $18 per 25-pounds. We have a largeselection of glazes (23 high temperature and 18 low temperature), slips and washes,and offer low, mid, and high temperature firing (cone 04, cone 2, & cone 10).

CLAY BODIESGHP clay bodies have been tested and in use at GHP for decades. The recipes herein

were not developed by members of the Pottery but rather were introduced throughcontact with their inventors; therefore, we cannot take credit for them. All clay bodiesare suitable for Handbuilding and Throwing. The first 3 clay bodies can be used for

both high-fire and low-fire and used in reduction or oxidation atmospheres, a lthoughresults vary according to atmospheric conditions and the temperature reached withinthe kiln. The DiCarlo Earthenware is a low-fire clay body and is not formulated fortemperatures above 04 (Cone) firings (though we use it to good effect in our 2firings).

High-fire indicates the clay bodies are formulated to vitrify at or around 10.

Typically, though not always, high temperature firings occur within a reductionatmosphere. Low-fire indicates the clay bodies are formulated to mature at or around

04. Low temperature clay and firings are likely fired in an oxidation or neutralatmosphere.

Our clays are shipped premixed dry (except our grolleg porcelain which comespremixed wet) from Amherst Potters Supply in Hadley, Massachusetts and can bepurchased directly from them. On the web: amherstpotters.com phone: 413-586-4507

SHRINKAGE TESTMake eight test bars of each clay, two bars for each firing temperature for betteraccuracy. Make the test bars 5 L x 2 W x thick and mark a 10cm line with shortperpendicular lines across the ends of the line. To calculate the shrinkage, measureeach clay bar from wet to dry and from dry to 06, 04, 2, 10.

Wet to dry: Line wet Line dry X 100 = % shrinkageLine wet

Dry to Fired: line dry line fired X 100 = % shrinkageLine dry

Wet to dry % + Dry to fired% = % total shrinkage

On average: Earthenware shrinks about 10%Stoneware shrinks about 12 15%Porcelain shrinks about 15 17%

ABSORPTION TESTUsing the fired clay bars from the shrinkage test, weigh each bar dry. Boil the bars in

water for an hour, remove each separately, blot it and reweigh:

Fired weight wet fired weight dry X 100 = % of absorptionFired weight dry

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CLAY BODY RECIPEST-1 STONEWARE SCULPTURE BODYFiring Range: 06-12, Oxidation or Reduction

Shrinkage: Green = 7%, 06 = 8%, 04=8%, 2=11%, 10=13%Porosity: 06 =10.9%, 04=10.3%, 2=4.9%, 10=1.3%

Color/texture: Orange-tan with iron brown specks dense with good green strengtIngredients: Measurements are in POUNDS

Hawthorne Bond Fire clay 200Thomas Ball clay 28Lizella 20Bentonite 11

Fine grog 70Medium grog 30

STONEWARE THROWING BODY (JEFF OESTREICH)Firing Range: 06-12, Oxidation or Reduction

Shrinkage: Green = 6%, 06 =7%, 04=8%, 2=12%, 10=15%

Porosity: 06 =13.5%, 04=12.7%, 2=4.3%, 10=.4%Color/texture: Tan-Brown, speckled in reduction smooth clayIngredients: Measurements are in POUNDS

Hawthorne Bond Fire clay 200OM-4 Ball Clay 50G-200 Feldspar 30Fine grog 30Red Iron Oxide 6

WHITE STONEWARE (GREG PITTS)Firing Range: 06-12, Oxidation or Reduction

Shrinkage: Green = 6%, 06 =6%, 04=6%, 2=10%, 10=13%

Porosity: 06 =14.2%, 04=13.1%, 2=6.7%, 10=.1%Color/texture: White to grey in reduction smooth and plasticIngredients: Measurements are in POUNDS

Foundry Hill Cream 40G-200 feldspar 40Flint 325 40Tile #6 40XX Saggar 30Pyropholite 10Bentonite 4

EARTHENWARE (DICARLO)Firing Range: 06-2, Oxidation or Neutral

Shrinkage: Green = 6%, 06 =6%, 04=9%, 2=14%, 10=10%

Porosity: 06 =9.6%, 04=6.9%, 2=0.3%, 10=0.3%

Color/texture: Red, smoothIngredients: Measurements are in POUNDS

Redart 130Goldart 30Hawthorne Bond Fire clay 20Talc 20Fine Grog 2

PORCELAIN (grolleg)Firing Range: 06-10, Oxidation or Reduction

Shrinkage: Green =4%, 06 =5%, 04=5%, 2=8%, 10=14%

Porosity: 06 =15.1%, 04=15%, 2=10.2%, 10=0.4%Color/texture: White, smoothIngredients: Not Available


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ORTON STANDARD CONES AND TEMPERATURES: See page 28High Temperature 10 (2377F)

Mid-range Temperature 2 (2124F)

Low Temperature 04 (1958F)

Bisque 06 (1823F)

GLAZESLike our clay body recipes our glaze recipes come from many sources. The 10 and

04 glazes at GHP are food safe unless otherwise noted.* This means our glazes are

chemically stable and contain no lead, barium or other toxic material. Whether or nota glaze is food safe is determined by a number of factors: glaze and ceramic

maturity, glaze-melt, and solubility or stability of fired glaze materials. Our non-food-safe glazes are so designated because they are unstable in the fired state and mayleach metal oxides into foods, especially acid foods that come into contact with them.Most of our matte 04 glazes are not food safe for this reason, because their matteness

is achieved essentially by underfiring, which leaves them unstable.

For a surface to be food safe it must be properly sealed (i.e. clay and glaze havebonded properly and fired to maturity). High-fire clays that have not been fired tomaturity (i.e. 6-10) have not had sufficient temperatures to vitrify the clay and bondglaze to ceramic. Low-fire glazes on high-fire bodies will tend to craze and peel off,

because their thermal expansion is not suited to the high-fire clay. Food and liquid canpenetrate the glaze surface. For this reason we consider our low-fire glazes food-safeONLY when applied to the low-fire earthenware.

*To be certain of the safety of a glaze have your pottery tested by the BrandywineScience Center. phone: 610-444-9850 web: www.bsclab.com/bsclab_pottery.htm

NOTES ABOUT GLAZE APPLICATION PROCESSESAll glazes are affected by glaze application including but not limited to, the thicknessof application, thoroughness of mix, specific gravity (relative density), thickness of the

bisqueware, peak temperature achieved, the surrounding ware and firing atmosphere.Tips:

1. Bisque the object2. Quickly rinse under running water, let dry completely3. Stir the glaze thoroughly be sure to stir the bottom and sides of bucket4. If using wax or latex resist allow to dry completely before glazing5. Use dipping tongs if necessary and shake remaining glaze off immediately

wipe the foot and the lid/gallery6. Know the glaze and your desired application (this takes experimentation)7. If the glaze begins to crack and peel when drying, rub cracks with a damp

finger to hinder further cracking and encourage adhesion

MIXING GLAZESEquipment:

1. A triple beam gram scale for measuring.2. 5-gallon bucket - A 10,000-gram batch of glaze will fit in a 5-gallon bucket.3. Jiffy mixer and drill.4. Sieve - A 60-mesh or an 80-mesh sieve.5. Dust mask.

Procedure:1. Calculate the quantity of glaze desired.2. Measure the materials using scale; add to an appropriately sized container.3. Dry mix the measured materials in the container avoiding raising dust.4. Wet mix by adding about 2/3 by volume.5. Sieve the glaze through a 60-mesh or 80-mesh sieve at least 2 times to

remove lumps and evenly distribute materials.

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10 High-fire GLAZES 10,000 grams fill a 5-gallon bucketADAM WELCHS AVERAGED SHINO (AKA NEW SPOTTED SHINO)Color: Semi-transparent rust red to white with carbon-trapping, dry red when thin.Ingredients: Measurements in GRAMS

Nepheline Syenite 3800Spodumene 1700OM 4 Ball Clay 1100EPK (or Georgia) 1000Kona F4 Soda Spar 1000Custer Feldspar 400

Red Art 200Soda Ash 800

BYRD MATTEColor: Opaque matte spotted brown to tan, glossy & blue grey on whitewareIngredients: Measurements in GRAMS

Nepheline Syenite 6500Dolomite 2100Zircopax 900OM 4 Ball Clay 500Bentonite 300Manganese Dioxide 200Cobalt Carbonate 50

CHARLIE D BLACKColor: Opaque semi-gloss black, breaks bluish-black over whitewareIngredients: Measurements in GRAMS

Nepheline Syenite 2000Kona F-4 Feldspar 2000Silica 2000Dolomite 1500Talc 1300OM 4 Ball Clay 1000

Whiting 200Cobalt Oxide 500Mason Stain 6600 300 (Black)Manganese Dioxide 300Bentonite 175Epson Salts 200 (Dissolve in hot water)

CHINESE WHITE (CRACKLE) (NOT STOCK GLAZE)Color: Opaque glossy toilet whiteIngredients: Measurements in GRAMS

Custer Feldspar 8300Zircopax 1000

Whiting 900Silica 800


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CHUN BLUEColor: Opaque gloss orange rust to mottled baby-blue with some violet on whitewareIngredients: Measurements in GRAMS

Kona F-4 Feldspar 4556Silica 2944Gerstley Borate 952Dolomite 952

Whiting 281Zinc Oxide 184EPK 130Bentonite 100Copper Carbonate 82Rutile 433

Tin Oxide 281

CHUN REDColor: Opaque glossy mottled red to pink-grey when thin on stonewareIngredients: Measurements in GRAMS

Custer Feldspar 4230Silica 2680Gerstley Borate 880Dolomite 880Strontium Carbonate 400Tin Oxide 260

Whiting 260EPK 230Zinc Oxide 180Copper Carbonate 50

DARK CELADONColor: Transparent glossy olive green, darker green on stonewareIngredients: Measurements in GRAMS

Kona F-4 Feldspar 4400Silica 2800

Whiting 1800EPK 1000Barnard Clay 1200

DON REITZ GREENColor: Opaque matte green to black when thinIngredients: Measurements in GRAMS

Nepheline Syenite 7067EPK 707

Petalite 1519Whiting 507Gerstley Borate 202Cobalt Carbonate 101Rutile 101

***EMILYS PURPLE (No Longer in Use)Color: Opaque semi-gloss creamy purpleIngredients: Measurements in GRAMS

Custer Feldspar 4100Silica 2000Talc 1500Gerstley Borate 1200Dolomite 700OM4 Ball Clay 500Tin Oxide 200

Bentonite 200Cobalt Oxide 100

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***GOATS MILK (No Longer In Use)Color: Matte rosy white to mottled tanIngredients: Measurements in GRAMS

Custer Feldspar 3193Dolomite 2317EPK 2140Spodumene 2140

Whiting 210Macaloid 100

***HAMADA GREEN (No Longer In Use)Color: Matte mottled green with blacks

Ingredients: Measurements in GRAMSG-200 Feldspar 5860Barium Carbonate 2370

Whiting 990OM4 Ball Clay 790Copper Carbonate 300Red Iron Oxide 290Rutile 230Tin Oxide 90

HIGH ALUMINA MATTEColor: Matte speckled tan to brown, off-white, and hints of lavender on whitewareIngredients: Measurements in GRAMS

Custer Feldspar 4890EPK 2510

Dolomite 2240Whiting 350Epsom Salts 200 (Dissolve in hot water)

MALCOLMS ULTRA CARBONTRAP SHINO (NOT STOCK GLAZE)Color: White to Black lots of Carbontrapping (Works best on porcelain)Ingredients: Measurements in GRAMS

Nepheline Syenite 4500EPK 2000Ball Clay (OM4) 1520Kona F4 Feldspar 1080Soda Ash 1900Red Art (optional) 660

***MAMO GREEN (No Longer In Use)

Color: Matte rusty brown to pale rosy greyIngredients: Measurements in GRAMS

G-200 Feldspar 4850Grolleg 2080Dolomite 1880Tin Oxide 790

Whiting 400Black Copper Oxide 150

NELSONS CELADONColor: Transparent glossy light green to icy-green on porcelainIngredients: Measurements in GRAMS

Kona F-4 Feldspar 4400Silica 2800

Whiting 1800

EPK 1000Red Iron Oxide 100Bentonite 100


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OESTREICH TENMOKUColor: Opaque glossy black. Breaks brown on whiteware, persimmon on stonewareIngredients: Measurements in GRAMS

Custer Feldspar 4838Whiting 1164EPK 537Silica 2014Zinc Oxide 224Barium Carbonate 224Bentonite 300Red Iron Oxide 805

OLD YELLOWColor: Opaque satin bright buttery yellow to ochre, deeper yellow on stonewareIngredients: Measurements in GRAMS

Nepheline Syenite 6390Dolomite 2110Zircopax 1600OM 4 Ball Clay 430Red Iron Oxide 100Bentonite 300Epson Salt 200 (Dissolve in hot water)

***ORANGE SATIN MATTE (No longer in use) Color: Semi-gloss to satin rusty brown to orange to buttery yellowIngredients: Measurements in GRAMS

Custer Feldspar 4970EPK 2360

Whiting 2010Talc 380Bone Ash 280Red Iron Oxide 240Rutile 240

ORIBEColor: Semi-gloss iridescent darkish greenIngredients: Measurements in GRAMS

Custer Feldspar 3090Silica 2530

Whiting 2240EPK 1250

Talc 780Bone Ash 110Black Copper Oxide 550

PERSIMMON (NOT STOCK GLAZE)Color: Glossy mottled red-brownIngredients: Measurements in GRAMS

G-200 Feldspar 4860Silica 2160Bone Ash 990

Whiting 720Talc 630EPK 630Red Iron Oxide 1080

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PFARR PINK (NOT STOCK GLAZE)Color: Opaque satin pepto pinkIngredients: Measurements in GRAMS

G-200 Feldspar 4000Silica 3000EPK 1000Dolomite 700Strontium Carbonate 600

Whiting 310Red Iron Oxide 150Cobalt Carbonate 25Mason Stain 6020 783 (Pink)

SCHERZER (PETE) REDColor: Opaque satin matte brick red to golden ochre metallic black where thin or thicIngredients: Measurements in GRAMS

Grolleg 3700Silica 1900Pearl Ash 1100Custer Feldspar 700

Whiting 2600Red Iron Oxide 1000Bone Ash 300

RUTILE GOLD MATTEColor: Opaque satin matte yellow gold with blues on whiteware, runny if thickIngredients: Measurements in GRAMS

Custer Feldspar 4900OM 4 Ball Clay 2500Dolomite 2250

Whiting 350Rutile 800

***SPOTTED SHINO (No longer in use)Color: Opaque glossy coppery luster to gold iridescenceIngredients: Measurements in GRAMS

Nepheline Syenite 4000Spodumene 3000OM 4 Ball Clay 1700Soda Ash 800 (Dissolve in hot water)EPK 500Bentonite 200

SUES CLEAR (10 CLEAR)Color: Transparent gloss icy greenish clearIngredients: Measurements in GRAMS

G-200 feldspar 2500Whiting 2500EPK 1800Silica 3500Gerstley Borate 120Tin Oxide 100

TEMPLE WHITEColor: Opaque satin creamy white, white to tan on stonewareIngredients: Measurements in GRAMS

G-200 Feldspar 3470EPK 2360Silica 1890Dolomite 1960

Whiting 310


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***TENMOKU (No longer in use)Color: Gloss metallic brown to blackIngredients: Measurements in GRAMS

Custer Feldspar 5100Silica 2370

Whiting 1370EPK 630Barium Carbonate 260Zinc Oxide 260Red Iron Oxide 950Bentonite 230

***T-PET CLEAR (No longer in use)Color: Transparent glossy clear slight green tintIngredients: Measurements in GRAMS

Silica 3330Petalite 2380

Whiting 2380EPK 1900Manganese carbonate 290

VAL CUSHING BLUEColor: Matte blue to black where thickIngredients: Measurements in GRAMS

Cornwall Stone 4600Whiting 3400EPK 2000Cobalt Carbonate 200

VAL CUSHING GREENColor: Matte blue-green to black where thickIngredients: Measurements in GRAMS

Cornwall Stone 4600Whiting 3400EPK 2000Tin Oxide 400Copper Carbonate 400

WHITE SHINOColor: Opaque glossy orange salmon to white. Crawls when thickIngredients: Measurements in GRAMS

Nepheline Syenite 4500Spodumene 1520OM 4 Ball Clay 1500Kona F-4 Feldspar 1080EPK 1000Soda Ash 400 (Dissolve in hot water)

***Winns Turquoise (No longer in use)Color: Semi-gloss turquoiseIngredients: Measurements in GRAMS

Kona F-4 Feldspar 5000Strontium Carbonate 2730Silica 910EPK 910

Dolomite 460Copper Carbonate 280Bentonite 170

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YING CHING BLUEColor: Transparent glossy light to medium blueIngredients: Measurements in GRAMS

G-200 Feldspar 4000Silica 3000EPK 1000Dolomite 700Strontium Carbonate 600

Whiting 310Red Iron Oxide 150Cobalt Carbonate 25

04 Low-Fire GLAZESANDREA GILLS MAJOLICAColor: Opaque semi-gloss whiteIngredients: Measurements in GRAMS

Frit 3124 6600Kona F-4 Feldspar 1800EPK 1000Nepheline Syenite 600Zircopax 1500Bentonite 300

CHINESE GREEN (NOT FOOD SAFE)Color: Texture matte pale green with copper flecksIngredients: Measurements in GRAMS

Nepheline Syenite 975OM 4 Ball Clay 1875EPK Kaolin 1875Gerstley Borate 900Silica 1875Lithium Carbonate 375Copper Carbonate 225

DEBS BASEColor: Transparent glossIngredients: Measurements in GRAMS

Frit 3195 4500Frit 3134 3000EPK 2500

DEBS BLUEColor: Deep sea blueIngredients: Measurements in GRAMS

Frit 3195 3600Frit 3134 2400EPK 2000Copper Carbonate 200Cobalt Carbonate 40

DEBS MOSS GREENColor: Translucent Light to medium mossy greenIngredients: Measurements in GRAMS

Frit 3195 3600Frit 3134 2400

EPK 2000Copper Carbonate 200Burnt umber 320


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DEBS ORANGE-REDColor: Orange-redIngredients: Measurements in GRAMS

Frit 3195 3600Frit 3134 2400EPK 2000Mason stain 6026 400 (Lobster encapsulated stain)

DEBS PURPLEColor: Light to medium lavenderIngredients: Measurements in GRAMS

Frit 3195 3600

Frit 3134 2400EPK 2000Mason Stain 6385 240 (Pansy Purple)Cobalt Carbonate 24

FAT YELLOWColor: Translucent gloss Bright acid yellowIngredients: Measurements in GRAMS

Frit 3124 8500EPK 1000Flint 500Mason Stain 6450 800 (Praseodymium)Bentonite 300

***HONEY AMBER (NO LONGER IN USE)Color: Transparent glossy Honey amberIngredients: Measurements in GRAMS

Frit 3124 2700Gerstley Borate 2340Nepheline Syenite 1800EPK 900Silica 900Lithium Carbonate 360Red Iron Oxide 540

***JACKIES BASE (NO LONGER IN USE)Color: Opaque satinIngredients: Measurements in GRAMS

Gerstley Borate 3800

Lithium Carbonate 1000Nepheline Syenite 500EPK 500Silica 4200Bentonite 200

JACKIES IVORYColor: Semi-matte pearlescent ivoryIngredients: Measurements in GRAMS

Gerstley Borate 3040Lithium Carbonate 800Nepheline Syenite 400EPK 400Silica 3360

Bentonite 80Light Rutile 320Zircopax 480

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JACKIES PEACOCK BLUEColor: Semi-matte mottled peacock blueIngredients: Measurements in GRAMS

Gerstley Borate 3040Lithium Carbonate 800Nepheline Syenite 400EPK 400Silica 3360Bentonite 80Copper Carbonate 240

KATHYS AMBER

Color: Transparent glossy Honey amberIngredients: Measurements in GRAMS

Frit 3124 3000Gerstley Borate 3000Nepheline Syenite 2000EPK 1000Silica 1000Red Iron Oxide 400

KATHYS TURQUOISEColor: Transparent glossy bright turquoiseIngredients: Measurements in GRAMS

Frit 3195 3000Gerstley Borate 3000Nepheline Syenite 2000EPK 1000Flint 1000Copper Carbonate 200

KD CLEARColor: Transparent gloss ClearIngredients: Measurements in GRAMS

Frit 5301 1430Gerstley Borate 5350Silica 1430EPK 2860

KRAWL BLUE/PURPLE (NOT FOOD SAFE)Color: Textured opaque dry stony matte Turquoise to cobalt blue

Ingredients: Measurements in GRAMSBarium Carbonate 4400Nepheline Syenite 2000Lithium Carbonate 500Silica 1100EPK 2000Copper Carbonate 700

PAD ALGAE (NOT FOOD SAFE)Color: Textured sulfur yellow to blackIngredients: Measurements in GRAMS

Lithium Carbonate 2090Nepheline Syenite 5600EPK 875

Magnesium Carbonate 40Rutile 480Chrome Oxide 240


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***PAD BASE SNOW WHITE (NOT FOOD SAFE) NO LONGER IN USEColor: Opaque crystalline matte snow white, runnyIngredients: Measurements in GRAMS

Lithium Carbonate 2625Nepheline Syenite 6335EPK 995Magnesium Carbonate 45

PAD DUSKColor: Light turquoiseIngredients: Measurements in GRAMS

Lithium Carbonate 2090

Nepheline Syenite 5600EPK 875Magnesium Carbonate 40Rutile 240Mason Stain 6319 3000 (Lavender Stain)

ROBS SATIN MATT BLACKColor: Opaque satin BlackIngredients: Measurements in GRAMS

G-200 Feldspar 2400Whiting 880Zinc 400Gerstley Borate 900Frit 3124 1920EPK 800Manganese Dioxide 640Copper Carbonate 400Red Iron Oxide 160Chrome Oxide 80

WEIRD BASEColor: Semi-transparent satin matte ClearIngredients: Measurements in GRAMS

Gerstley Borate 5000Wollastonite 5000

***WOODYS TURQUOISE (NO LONGER IN USE)Color: Transparent glossy bright turquoiseIngredients: Measurements in GRAMS

Frit 3124 2700Gerstley Borate 2340Nepheline Syenite 1800EPK 900Flint 900Lithium Carbonate 360Copper Carbonate 180

04-10 Low to High-fire SLIPSBARRYS FISH SAUCE (HIGH FIRE SLIP BASE)Color: Matte WhiteIngredients: Measurements in GRAMS

Grolleg 4370Kona F-4 Feldspar 2350

Silica 1560Bentonite 940Pyrophyllite 780

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BLACK SLIPColor: Matte Black to BrownIngredients: Measurements in GRAMS

Grolleg 2190Redart 2190Kona F-4 Feldspar 2350Silica 1560Bentonite 940Pyrophyllite 780Red Iron Oxide 500Black Iron Oxide 300Manganese Dioxide 300

Cobalt Oxide 100

COBALT SLIPColor: Matte BlueIngredients: Measurements in GRAMS

Grolleg 4370Kona F-4 Feldspar 2350Silica 1560Bentonite 940Pyrophyllite 780Cobalt Oxide 150

COPPER SLIPColor: Matte Yellow to GrayIngredients: Measurements in GRAMS

Grolleg 4370Kona F-4 Feldspar 2350Silica 1560Bentonite 940Pyrophyllite 780Copper Carbonate 400

KILN WASHColor: Matte WhiteIngredients: Measurements in GRAMS

Alumina Hydrate 5000Silica 5000

RED SLIPColor: Matte Red

Ingredients: Measurements in GRAMSGrolleg 2190Redart 2190Kona F-4 Feldspar 2350Silica 1560Bentonite 940Pyrophyllite 780Red Iron Oxide 500

RUTILE SLIPColor: Matte TanIngredients: Measurements in GRAMS

Grolleg 4370Kona F-4 Feldspar 2350Silica 1560Bentonite 940Pyrophyllite 780Rutile 800


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04 Low-fire SLIPSMARY BARRINGER04 WHITE SLIP (LOW FIRE SLIP)Color: Matte WhiteIngredients: Measurements in GRAMS

EPK 2500OM 4 Ball Clay 2500Nepheline Syenite 1500Frit 3124 1000Silica 2500

KIDS SLIPS + WHITE SLIPBlack Black Stain 6600 20%Blue Royal Blue Stain 6339 20%Brown Dark Brown Stain 6109 20%Green Leaf Green Stain 6265 20%Lavender Lavender Stain 6319 20%Purple Pansy Purple Stain 6385 20%Turquoise Turquoise Stain 6364 20%

Yellow Praseodymium 6450 20%Pink Deep Crimson 6006 20%

WASHES AND STAINSNotes About Mixing Washes and Stains

All these recipes are mixed into 1 pint of cold water to make a thin watercolor-likeconsistency. To make your own colored washes with stains, start with a 50:50 mix ofstain and Gerstley Borate and test. Add more Gerstley Borate if test is dry.

Notes About ApplicationWashes act like ink or watercolors and can be applied to bisque, over or under glaze. Ifa wash is applied to the foot of a pot it may pick up a little of the kiln wash when fired.

A typical application is to paint washes over Majolica, but they work well over Templewhite and White Sh ino as well. Wash can also be applied to the surface of bisquewareand then wiped clean leaving residue behind in the recessed areas. Please note that

washes are extremely concentrated colorants and will also act as fluxes in combinationwith glaze, often causing the glaze to run when applied heavily.

BLACK COPPER WASHColor: Matte BlackIngredients: Measurements in GRAMS

Gerstley Borate 100Black Copper Oxide 150

BLUE WASHColor: Matte Bright BlueIngredients: Measurements in GRAMS

Gerstley Borate 441EPK 87.75Mason Stain 6339 220.5 (Royal Turquoise Blue Stain)

GREEN WASHColor: Matte Green- brown when thinIngredients: Measurements in GRAMS

Gerstley Borate 441EPK 87.75Mason Stain 6209 220.5 (Chrome Green Mason Stain)

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RED IRON WASHColor: Matte Red to blackIngredients: Measurements in GRAMS

Gerstley Borate 100Red Iron Oxide 167

RUTILE WASHColor: Matte Yellow to tanIngredients: Measurements in GRAMS

Gerstley Borate 100Rutile 167

TERRA SIGILLATADirections for Mixing Terra Sigillata

You will need:Measuring cupOne-gallon container with lidLength of clear rubber or plastic flexible hose

Directions:1. Dissolve the soda ash in 1 cup of hot tap water then pour into the other 1

cups of cold water.2. Blend clays into this water and mix well. Be sure to break up any lumpsus

a mixer if available. Can ball-milled for 6 to 10 hours.3. Let stand, undisturbed, for 24 hours.4. Do not move the container, but carefully siphon off the uppermost, thinnes

liquid. Draw liquid from the surface and allow air to draw occasionally iorder to check the thickness. As soon as the liquid thickens, stop siphoninThis thin liquid drawn off the top is the Terra Sigillata. Dry the remaininthicker liquid and discard.

5. Adjust through the addition or evaporation of water to measure 1.2, or leson a hydrometer, or visually like skim milk.

Application:Terra Sigillata is applied to greenware with a soft brush. If you desire a burnishefinish, apply Sigillata to a bone-dry pot, a few square inches at a time. When the arehas lost its surface moisture but is still dark, rub with a soft cotton cloth, plastic baover your finger, the back of a spoon, or a stone. You may apply several coats, bmore than two can cause the Sigillata to flake. Terra Sigillata does not work well undeglaze because of its dense burnished surface making it less porous and less easy foglaze to adhere.

BLACK TERRA SIGILLATAColor: Opaque matte blackIngredients: Measurements in GRAMS

Redart 200Manganese 10Cobalt Carbonate 20Black Copper Oxide 10Sodium Silicate 2 drops

Water 14 cups

DARK BROWN TERRA SIGILLATAColor: Opaque matte dark brownIngredients: Measurements in GRAMS

OM 4 Ball Clay 50

Albany Slip 50Sodium Silicate 2 drops

Water 14 cups


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GREEN TERRA SIGILLATAColor: Opaque matte greenIngredients: Measurements in GRAMS

OM 4 Ball Clay 200Chrome Oxide 10Sodium Silicate 2 drops

Water 14 cups

LIGHT ORANGE TERRA SIGILLATAColor: Opaque matte light orangeIngredients: Measurements in GRAMS

OM 4 Ball Clay 50

Redart 50Sodium Silicate 2 drops

Water 14 cups

MAROON TERRA SIGILLATAColor: Opaque matte maroonIngredients: Measurements in GRAMS

OM 4 Ball Clay 180Manganese 5Red Iron Oxide 15Sodium Silicate 2 drops

Water 14 cups

NAVY TERRA SIGILLATAColor: Opaque matte navy blueIngredients: Measurements in GRAMS

OM 4 Ball Clay 200Manganese 10Cobalt Carbonate 20Copper Carbonate 10Sodium Silicate 2 drops

Water 14 cups

ORANGE TERRA SIGILLATAColor: Opaque matte orangeIngredients: Measurements in GRAMS

Redart 100Sodium Silicate 2 drops

Water 14 cups

RED TERRA SIGILLATAColor: Opaque matte glossy when burnished Brick redIngredients: Measurements in GRAMS

Newman Red 300Redart 1200Soda Ash 15

Water 14 cups

WHITE TERRA SIGILLATAColor: Opaque matte glossy when burnished WhiteIngredients: Measurements in GRAMS

OM 4 Ball Clay 500EPK 1000

Soda ash 15Water 14 cups

20

YELLOW TERRA SIGILLATAColor: Opaque matte yellowIngredients: Measurements in GRAMS

OM 4 Ball Clay 180Vanadium 20Sodium Silicate 2 drops

Water 14 cups

RepairsBISQUE REPAIRUses: Used to repair cracks in bisquewareIngredients:

White Glue 50%Sodium Silicate 50%

add: EPKWater until mixture is the consistency of mayonnaise.

GREENWARE PATCHUses: Repairs leatherhard clay cracks and breaksIngredients:

Vinegar 1 teaspoonKaro Syrup cupSoda Ash pinchNylon Fibers pinchPowder Clay till pasty consistency

MAGIC WATERUses: Aids to prevent cracking and supports joints.Ingredients:

Sodium Silicate 3 tablespoonsSoda Ash 5 grams

Water 1 gallon

Glossary of Terms and Materials:Information was collected from a combination of sources; see reference list an

bibliography on page 27.

Alumina Hydrate: (Al2O3 3H2O). A source of alumina used primarily for kiln wasand wadding.

Aluminum Oxide: (Al2O3). Known as alumina, this oxide is used in glazes, promoteviscosity, stability, gives hardness and durability.

Ash Glaze: A glaze made with wood or vegetative-derived ash.

Ball Clay: A fine particle highly plastic clay usually high in iron. In glazes ball clayadd alumina but also iron thus darkening the glaze. In clay bodies it adds plasticit

because of its particulate size.

Barium Carbonate: (BaCO3). A secondary flux in stoneware glazes, most frequentlused to produce a satin matte surface. Used in glaze to introduce the oxide, bari

which is an auxiliary flux in low and high-temperature glazes. Unsafe for low-firfunctional glazes.

Barium Oxide: (BaO). An auxiliary flux in earthenware frits and high-temperaturstoneware glazes. It is also introduced for its crystallizing properties which gives satimattes.

Barnard Clay: A high iron-bearing earthenware clay, or a substitute for Albany slip.


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Bentonite: (Al2O3 5SiO2 7H2O) Is an extremely fine particle highly plastic colloidalvolcanic clay. It is used to lend plasticity to clay bodies and used in glazes to keep themin suspension.

Bisque: The first firing of greenware in preparation for glazing. The low firingtemperature (we fire our bisque to 06 or 1823F) is sufficiently hard enough to

accept glaze without breaking.

Black Copper Oxide: (CuO). Coarser in grain size and yields more copper thancopper carbonate.

Black Iron Oxide: (FeO). Ferrous oxide.

Black Core: The dark grey center seen in shards, caused by a reduction atmosphere.

When too much carbon is introduced the ceramic body weakens and creates otherproblems such as dunting and/or bloating.

Blistering: Unwanted gassing of a glaze resulting in bubbles and craters of burstbubbles. Blistering occurs where the glaze has not had time to smooth out before itsets.

Bloating: Blistering of the clay body caused by trapped gases.

Bone Ash: Calcium phosphate. (Ca3 (PO4) 2). A high-temperature secondary flux inglazes. The essential ingredient in the production of bone china, giving it translucency.

An opacificier in low-temperature glazes.

Bone China: An English form of china.

Borate: A chemical compound which includes the element boron.

Borax: A powerful flux in glaze.

Burnishing: Polishing leatherhard clay by rubbing with a hard object like a smoothpebble or the back of a spoon.

Burnt Umber: A form of ochre with a significant manganese content.

Calcine: Through heating the material to red heat removes the chemically bondedwater giving it the same chemical content without the additional shrinkage.

Calcium Carbonate: Whiting. Limestone. (CaCO3) Carbonate of lime used tointroduce calcium oxide into glazes, it is the most frequently used flux in hightemperature glazes.

Casting Slip: A clay and water suspension used in the process of slip-casting.

Chattering: The rhythmic rippling which appears when trimming. It occurs when theclay is too hard or too soft or if the tool is not sharp enough or the wheel is turning to

fast.

China Clay:See Kaolin.

Chrome Oxide: Chromium Oxide. (Cr2O3). A colorant generally producing heavydark green colors. Chromium is found in chromate materials and is very refractory.

Clay: Hydrous Alumina Silicate (Al2O3 2SiO2 2H2O). All clay comes fromdecomposed feldspathic rock. There are primary and secondary clays. Primary arethose which are found at or close to their source and have a large particle size and arerelatively pure. Secondary clays have been removed from its source through water,

wind or weathering making the particles finer, and it has absorbed impurities.

Clay Body: Is a clay composition designed for particular working characteristics.Clay bodies have 3 essential constituents 1) clay 2) flux (feldspar) 3) filler (silica, grog).

Cobalt Carbonate: (CoCO3). Standard blue colorant in glaze and slip. The most

powerful of the coloring oxides and also a strong flux. More finely ground then theoxide which gives a more even color.

22

Cobalt Oxide: (Co3O4). The oxide form of cobalt. The most powerful of the colorinoxides and also a strong flux. More coarse then its carbonate form.

Coefficient of Expansion: The ratio of change of a material when heating ancooling.

Colemanite:See Gerstley Borate. (2 CAO 3 B2O3 5H2O)

Cones: ()See Pyrometric Cones. See Chart on page 28.

Copper Carbonate: (CuCO3). A main glaze colorant, copper compounds are capablof producing a wide range of colors and is very responsive to atmospheric changeinside the kiln.

Cornwall Stone: Cornish stone. It is a feldspathoid material more complex thapotash or soda feldspar and contains numerous trace elements.

Crack: An unwanted break in greenware, bisqueware or glazeware. There are severvarieties of cracking; each has a uniqueness that aids in discovering the reason for it.

Crawling: A glaze defect (sometimes desired) characterized by the way the glazseparates from the clay body and forms beading or bunching on the surface.

Craze: Crazing is a common glaze flaw characterized by the development of fincracks in the finished glaze. It is caused by the glaze contracting more then thceramic body. It can also be caused from glazing thickness or cooling too quickly ithe kiln.

Cross-Draught Kiln: Cross-Draft Kiln. Natural-Draft Kiln. Horizontal kiln in whichot gases travel through the ware across the chamber, typical of wood fired kilns.

Custer Feldspar:See Potash Feldspar.

Deflocculation: The action of dispersing the fine clay particles in a slip so that thslip becomes more fluid through the addition of soluble alkalis.

Dolomite: Calcium magnesium carbonate. (CaCO3 MgCO3). A high temperaturflux with a combination of calcium and magnesium. It has a matting effect in glazand promotes hard durable surfaces.

Down-Draught Kiln: Down-Draft Kiln. A kiln in which the flames are deflectedownwards throughout the chamber to use the heat evenly before it exits out thchimney located in the back or bottom of the kiln.

Dunting: Cracking of pottery caused by stress which forms during firing and coolinprimarily caused by differential contraction of body and glaze or fast cooling.

Earthenware: General name for wares made from low firing secondary clay

generally fired below

1 (2109F). Pottery made of a porous body fired at a lotemperature.

Earthenware Clay: Common, usually red, ground clays. They contain manimpurities. Clays that are low in maturing temperature and used to make earthenwarclays.

Egyptian Paste: A self-glazing clay body which is fired to a low temperature.

Electric Kiln: A kiln that uses electricity to heat the chamber in a neutral toxidizing atmosphere.

Engobe: Sometimes used interchangeably with slip, but it includes materials othethan clay. An engobe is halfway between clay and a glaze and fires to a more vitreoustate.

EPK:See Kaolin. Edward Plastic Kaolin. Mined in Florida.

Epson Salt: Magnesium sulfate: (MgSO4 7H2O). A flocculent used in glazes anslips to help keep particles in suspension.


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Eutectic: The lowest melting point of two or more substances that are combined andit is always lower than the melting point of any individual component.

Feldspar: (K2O Al2O3 6SiO2) Alumino-silicate mineral similar to clay, butproportionally higher content of fluxes. The most important single glaze material inhigh temperature firings as it contains all three necessary constituents.

Fireclay: Clay which has properties refractoriness or resistance to heat, though thevarieties may vary widely in properties. They are relatively pure and free from ironand have more coarse grain particles.

Firing: The process of converting clay to ceramic through heating until it becomesstone-like and unaffected by water.

Flint:See Silica. (SiO2).Flocculation: The action of altering the physical properties of fine particles in asuspension so that they no longer repel one another but aggregate into larger particlesand settle, a process used in the making of Terra Sigillata.

Flux: Any substance that lowers the melting point of a ceramic body or glaze.

Foundry Hill Cream: See Stoneware clay . A stoneware clay that fires to a creamcolor.

Frit: Frits are materials that have been combined and heated in glass and thenshattered removing potential toxicity hazards. In clay bodies they strengthen andimprove glaze fit, limiting problems of glaze defects and lowers the vitrification point.Frits are designated by a number which contain different materials.

G-200:See Potash Feldspar.

Gerstley Borate: (1CaO 1B2O3 5H2O). A flux used in glazes as a replacement forcolemanite.

Glaze: A substance that melts to a glassy state at a given temperature. It is a layer ofglass which is fused into place on a ceramic surface. Through the process of heating itrenders the ware food safe or gives the ceramic decoration. There are three necessaryconstituents for making a glaze, 1) Flux 2) Alumina 3) Glass-former.

Gold Art:See Stoneware clay.

Greenware: Clay that is still in working condition and has yet dried sufficiently forfiring.

Grog: Fired fireclay or other refractory clay which has been ground to various degreesof coarseness. In clay bodies it is used to counteract shrinking, warping and cracking.Grog comes in a variety of mesh sizes usually considered Coarse, Medium, or Fine,

identified by mesh size which corresponds to how many wholes in the screen per inch.20-mesh is more coarse then 40-mesh which is more coarse then 60-mesh.

Grolleg Kaolin:See Kaolin. An extremely pure English kaolin.

Hakame: A technique using slip applied with a wide often straw-like brush.

Hawthorne Bond Fire Clay: See Fire Clay.

High Temperature Firing: Is a range rather than one specific temperature. Therange generally varies from 6-14.

Hydrometer: Is an instrument used to measure the specific gravity of liquids; thatis, the ratio of the density of the liquid to the density of water.

Inlay: A decoration technique where lines are scored in clay and filled with anothercolor usually slip.

Jiggering: Forming a pot by using a spinning mould which shapes the inside of thepot.

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Jolleying: Forming a pot using a spinning mould which shapes the outside of the pot

Kaolin: China Clay. (Al2O3 2SiO2 2H2O). Very refractory. The purest natural claand the essential ingredient in making porcelain. It has a coarse grain structure annot very plastic. The coarse particle size is the result of its lack or erosion, as it isprimary clay found and mined at its source. A source of alumina in glazes.

Kona F-4:See Soda Feldspar.

Kiln: A structure built to contain heat in order to turn clay into ceramic. There armany varieties of kilns from electric to oil to woodburning; though the effects ardifferent the result is the same, turn clay into ceramic.

Leatherhard: Cheesehard. The stage which plastic clay reaches during drying whe

the clay can be picked up without distorting yet soft enough to work.Levigation: Refining clay by floating in water allowing the heavier particles to settl

while the smaller particles are taken off.See Terra Sigillata.

Limestone:See Calcium Carbonate.

Lithium Carbonate: (Li2CO3). An active alkaline flux with similar color responseas sodium and potassium. Reduces glaze expansion and promotes crystallization.

Lizella: A light red earthenware clay similar to Redart.

Low Temperature Firing: Is a range rather than one specific temperature. Thrange generally varies from 022-01.

Lustres: Metallic surfaces on glazes applied on top of glazes and re-fired.

Macaloid: Magnesium alumino-silicate. A refined white variety of bentonite, thoug

not quite as plastic.

Magnesium Carbonate: (MgCO3). A high temperature flux which producessmooth, buttery, matte surface similar to Dolomite.

Manganese Dioxide: (MnO2). Used in both high and low fire glazes and can badded to clay bodies.

Mason Stains: A U.S. suppler of stains used as colorants in glazes, clay bodies, anwashes.

Mid-Temperature Firing: Is a range rather than one specific temperature. Thrange generally varies from 1-6.

Molochite: Porcelain Grog. The trade name for calcined china clay.

Nepheline Syenite: (K2O 3Na2O 4Al2O3 8SiO2). Alternative to feldspar, it has

very active fluxing powers, with a high sodium content which may cause crazing.Neutral Atmosphere: When the atmosphere inside the kiln is neither oxidizing noreducing. Typically, an electric kiln fires in a neutral atmosphere going through boutof reduction and oxidation though predominantly the latter.

Newman Red:See Earthenware.

OM-4 Ball Clay: See Ball Clay. Old Mine #4 references which clay mine thiparticular ball clay comes from in Kentucky.

Onglaze: Overglaze. Ceramic color applied on top of the fired glaze surface and givean extra firing. The firing is at a lower temperature than the first glaze firing in ordethat the first fired glaze is undisturbed while the onglaze color fuses onto the originglaze surface.

Opacifier: Minerals which are included in glaze recipes for their ability to opacify

glaze, make opaque.Oxidation Atmosphere: An atmosphere in a kiln where there is a plentiful amounof oxygen enabling metals in clays and glazes to develop their oxide colors.


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Paper Clay: Aclay body that uses paper pulp as a filler to increase green strength.Usually the recipe contains between 5 49%.

Pearl Ash: Potassium Carbonate. (K2CO3). A highly soluble form of potassium,usually used in a fritted form.

Petalite: (Li2O Al2O3 8SiO). Feldspar-like material which contains lithium and hasa similar response as nepheline syenite but less likely to craze.

Pin-hole: A small smooth-edged hole in a glaze surface, usually occurring when abubble of gas bursts on the surface during firing.

Porcelain: A vitrified, white ceramic whose main ingredient is kaolin, fired to 9 orhigher.

Porosity: The ability of a fired body to absorb water.

Potash Feldspar: This is the most common form of feldspar and is the typegenerally used in glaze, having larger amounts of potassium than sodium.

Pyrometer: An indicator of temperature inside the kiln which is display in the formof a gauge, dial, or digital display.

Pyrometric Cones: () Developed in 1896 by Edward Orton Jr. Pyrometric cones

are used to measure the effects of time and temperature inside a kiln. They are madeof ceramic material and experience heat the same was as the ware making them moreaccurate temperature gauge. See cone chart on page 28.

Pyrophyllite: (Al2O3 4SiO2 H2O). A hydrous alumino-silicate material used toreplace some or all of the flint and feldspar in industrial tile clays. It brings about adecrease in thermal expansion.

Quartz:See Silica. (SiO2)

Quartz Inversion: Quartz Phase. The change in silica (alpha quartz and beta quartz)where the difference is in the angle of the silica-oxygen-silica bond which changes at1063F. The change occurs every time crystalline quartz passes this temperature in

either direction. There is a decrease in size which may cause cracks in the ceramicbody if it goes through this stage too quickly. There is a 2% increase in volume whichis reversible upon cooling. This stage happens when the kiln is just starting to developcolor.

Redart:See Earthenware Clay. Earthenware Clay with a high iron content.

Red Iron Oxide: Ferric oxide. (Fe2O3). Iron is the most common and most usefulcoloring oxides.

Reduction Atmosphere: Indicates an atmosphere where there is little oxygen dueto the presence of an excess of carbon from an incomplete combustion process. Theeffect this has is to turn all the materials that were oxides back into their metal state.

Refractory: Resistant to heat or capable of withstanding high-temperatures.

Relative Density: (previously called specific gravity). Is expressed as a number foreach material which specifically represents the weight of a chosen volume of thematerial. Since 1ml (cc) of water weighs 1 gram the relative density is the same as the

weight in grams of 1 cc of the material.

Rutile: (TiO2). A natural source of titanium, usually containing some impurities inthe form of iron and occasionally chromium and vanadium. It is used to producemodified iron colors. It has strong effects on other colors.

Saggar: A refractory box used to protect ware from direct contact with flames andgases. A secondary use is to produce an artificial atmosphere within the saggar

creating localized reduction.

26

Saggar clays: Similar to fireclays and as smooth as ball clays, used as an addition tstoneware, terra cotta, and earthenware bodies.

Sgraffito: A decorative technique where one scratches through some contrastincolored slip into the clay body beneath.

Shivering: A glaze defect in which slivers of glaze shear away form the pot, it is thresult of poor glaze fit as the glaze shrinks less than the clay body and is the oppositof crazing.

Silica: Silicon Dioxide. Flint. Quartz. (SiO2). The main glass-former and the moscommon source of silica in both glazes and clay.

Slip: A mixture of clay and water used for coating clays, generally applied to th

surface of greenware to change its color, texture and/or to add decoration. Becausslip is made of clay it shrinks as the clay shrinks which allows it to be applied to weand/or leather-hard clay. If applied to bisque do not apply too thickly as it will likelcrack and/or flake off.

Soda Ash: Sodium Carbonate. (Na2CO3). The common source of sodium for glazes.

Soda Spar: Sodium Feldspar. (Na2 O Al2O2 6SiO2) The second common form ofeldspar used as a body flux and in glazes as a silicate provider. Less common thepotash feldspar though very similar in performance. Higher levels of sodium thepotassium.

Sodium Silicate: Water-glass. (Na2SiO3) Sodium oxide and silica combined in equproportions and used as a clay deflocculant. Don Bendel says: makes water wetter!

Specific Gravity:See Relative density.

Spodumene: (Li2O Al2O3 4SiO2). A lithium alumino-silicate, similar in behavior tpetalite. Used in glazes and in flameproof bodies.

Stains: Prepared stains. Prepared oxides. Inorganic coloring agents usuallpurchased in powdered form for adding to bodies, slips, washes, and glazes.

Stoneware: A hard, strong and vitrified ware fired to a high temperature in whicthe body and glaze mature. Named for its physical resemblance to stone. 2109 F

2381F (6 14)

Stoneware Clay:Are clays that mature between 5 11. They vary in plasticity an

firing range and there is no great distinction between saggar, fire and stoneware clays.

Strontium Carbonate: (SrCO3). A rare alkaline earth used as a flux in both a clabody and glaze.

Talc: Magnesium Silicate. (3MgO 4SiO2 H2O). A secondary flux in glazes and cla

bodies particularly in low temperatures. Promotes smooth buttery surfaces.

Terracotta: Earthenware ceramics both glazed and unglazed. It comes from Italiaand means fired earth.

Terra Sigillata: Latin for sealed earth. A slip that has been refined by repeatelevitations and deflocculated. It has an extremely fine particulate structure and iusually burnished to a high polish. Best if fired between 08-02.

Thermal Expansion: Expansion in volume of matter that is experienced iconjunction with temperature change.

Thermal Shock: The stress created within a ceramic object by temperature changcaused by the shrinkage and expansion of the ceramic body.

Thomas Ball Clay:See Ball Clay.

Tile #6:See Kaolin. A type of kaolin mined in Georgia.


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Tin Oxide: (SnO2). The most widely used opacifying agent. Used as a whitener forglazes and is good at all temperatures.

Up-Draught Kiln: Up-Draft kiln. A kiln in which the hot gases and flame passupwards through the ware to the chimney or just out of the roof.

Vanadium: Vanadium Pentoxide. (V2O5) Is used to produce yellow colors.

Vitrify: Is the hardening, tightening, and finally, the partial glassification of clay,giving fired clay its hard, durable, dense and rock-like properties.

Volatilize: To change from a liquid or solid into a vapor.

Wedging: The clay preparation involving the kneading of clay to thoroughly mix andexpel air bubbles.

Whiting:See Calcium Carbonate.

Wollastonite: Calcium Metasilicate. (CaO SiO2). A natural calcium silicate whichcan be used as a replacement for whiting and flint. Reduces firing shrinkage and addsthermal shock resistance in bodies and glazes.

Wood Firing : Firing clay into ceramic with the use of wood as a source of fuel anddecoration.

XX Saggar:See Ball Clay.

Zinc Oxide: (ZnO) A useful flux from mid to high temperature. Very active producingbrilliant, glossy, smooth, trouble-free glazes.

Zircopax: Zirconium Silicate. (ZrSiO4). Opacifier generally produce cool white glazesand adds to the fluxing action of the glaze. Zirconium compounds are more stable

than tin.

References and Bibliography:The books listed below are excellent resources and are often the direct link to theinformation contained herein.-Bendel, Don, Rice, Paula. Ceramics. Flagstaff, AZ. Northern Arizona University.

1998.-Cushing, Val. Cushings Handbook. 3rd Edition. 1994-Fournier, Robert.Illustrated Dictionary of Practical Pottery. 4th Edition. 2000.-Hamer, Frank and Janet. The Potters Dictionary of Materials and Techniques. New

York: Watson-Guptill, 1991.-Hopper, Robin. The Ceramic Spectrum. Radnor PA: Chilton Book Company, 1984.-Peterson, Susan. The Craft and Art of Clay . Englewood Cliffs, NJ: Prentice Hall,

1992.

-Pitelka, Vince. Clay: A Studio Handbook. Westerville, OH. The American CeramicSociety. 2001.-Rhodes, Daniel. Clay and Glazes for the Potter. Chilton Book Company, 2nd RevisedEdition. 1996-Rhodes, Daniel. Ed. Robin Hopper. Clay and Glazes for the Potter. Iola, WI. KrausePublishers. 3rd Edition. 2000.-Rosenbaum, Allen. VCU Ceramic Department Technical Handbook. Richmond, VA.2000

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Orton Pyrometric Cone Chart

http://www.ortonceramic.com/resources/pdf/wall_chart_degreeF.pdf


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greenwich house pottery clay and glaze

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