Powdered raw clay minerals that are mined, ground, screened and bagged for use in the mixing of glazes and clay bodies. Most are 'unaltered' and come straight from the earth to the end user.
#6 TILE CLAY: An air-floated kaolin with bright firing properties yet highly plastic. It offers high green strength for superior jiggering and wet processing properties.
BENTONITE: Extremely plastic clay formed from decomposed volcanic ash. Used to add plasticity to clays and to keep glazes in suspension. Up to 2% can be added to clay bodies and up to 1% in glazes with few adverse effects. Most bentonites swell (some up to 15 times their size) when added to water. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
C & C BALL CLAY: A highly plastic, light colored secondary (sedimentary) clay that vitrifies in the 2012° F to 2192° F range. Sometimes called blue or black clay depending on the amount of organic material present. Used to add plasticity to throwing clay and fluidity & green strength to casting slips. If used in high percentages excessive shrinkage may occur. The term ‘ball’ clay comes from the old hand mining technique where small blocks were cut from deposits, the corners of which would get knocked off during handling and storage, leaving roundish balls of clay. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
E.P. KAOLIN(Edgar Plastic Kaolin / E.P.K.): A primary clay with moderate plasticity that is prized for low iron content which imparts a very clean white color. Sometimes called china clay, kaolin is used as a prime source for Alumina Oxide and Silica in glazes. Due to its high Aluminum Oxide content, kaolin is a refractory with a melting point over 3218° F. E.P. Kaolin is mined in Edgar Florida and chemically is very close to the theoretical kaolin make up, making it a good substitute for other kaolin’s with similar properties. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
GOLD ART CLAY: A plastic stoneware clay mined in Southern Ohio by Cedar Heights. A very versatile clay that can be used alone or as a ball or fire clay in clay and glaze mixes. It fires to a light golden buff color, is an air floated 200 mesh particle size and fires from cone 06 -12. Can be used as a substitute for Jordan Fireclay. Acute Affect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis. GREENSTRIPE FIRECLAY: An air floated and flash dried Lincoln Fireclay. It is a secondary clay, high in Aluminum Oxide and refractory with a melting point of 2970° F. Fires a buff color in oxidation and a brown color in reduction. Fireclay deposits were formed over 200 million years ago and most are found under coal seams. Due to the nature of their formation they all contain high amounts of volatiles (materials that burn out during firing) and slow firing is recommended if large amounts are used in clay bodies. Some grogs are made of fired and crushed fireclays. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
GROLLEG KAOLIN: A blended English primary kaolin of moderate plasticity, low shrinkage, high melting point (2012° F) and a very low iron content lending to its snowy white color. An excellent kaolin for making translucent porcelain bodies due to its low titania content. With a flux content higher than other kaolin, less feldspar is needed to achieve vitrification. Its plasticity can be an issue for thrown bodies, as the addition of most plasticizers may impact the clean whiteness of the clay. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
HAWTHORN BOND: A Missouri fire clay that fires a light buff color at cone 10. This fireclay like all fireclays is a refractory and it has good plasticity. Very similar to AP Green fireclay in its properties but at a lower cost. Fireclay deposits were formed over 200 million years ago and most are found under coal seams. Due to the nature of their formation they all contain high amounts of volatiles (materials that burn out during firing) and slow firing is recommended if large amounts are used in clay bodies. Some grogs are made of fired and crushed fireclays. Acute effect: Mild irritant. chronic effect: May be hazardous over long term due to silicosis. KT 1-4 BALL CLAY: Mined in the Kentucky Tennessee Valley this coarse grained cone 10 ball clay is a blend of K-T clays SGP#1 and OM#4 clays. Since KT1-4 is blended it allows for a more exact and stable product that is adjusted to compensate for mineral shifts in the two base clays. While not the most plastic of ball clays it is one of the preferred ball clays for making casting slips. Kentucky Tennessee ball clays are low in carbon which helps prevent the formation of gas bubbles in glaze mixtures that are stored for lengths of time. The term ‘ball’ clay comes from the old hand mining technique where small blocks were cut from deposits, the corners of which would get knocked off during handling and storage, leaving roundish balls of clay. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
KENTUCKY STONE CLAY: A coarse grained ball clay mined in the Kentucky-Tennessee Valley area with good plasticity, high strength and firing temperature into the cone 10 + range. Generally stone clays are ball clays that contain more sand and color impurities. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis. NEWMAN RED CLAY: A high fire California clay that is low in plasticity with powerful staining properties. The raw clay is orange in color but fires a bright rich red, used to color plastic clays and casting bodies. Its coloring abilities are so strong that recipe amounts can many times be cut in half and still produce rich reds in oxidation clay bodies. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
OM# 4 BALL CLAY: A strong, fine grained, highly plastic ball clay named for its source, Old Mine # 4 located in Kentucky. OM#4 is an industry standard widely used as a suspension agent in glazes, excellent for casting slip suspensions and provides superior plasticity in thrown clay bodies. Its melting point is 3000°F and it does contain some soluble salts. The term ‘ball’ clay comes from the old hand mining technique where small blocks were cut from deposits, the corners of which would get knocked off during handling and storage, leaving roundish balls of clay. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
RED ART CLAY: A 200 mesh air floated iron red clay with moderate plasticity, low shrinkage and a firing range of cone 04-1. Colors will vary with firing conditions and temperatures with the richest color achieved at cone 02. This type of red earthenware clay has been used to make flower pots for many years and is often called flowerpot red. Gardeners will use iron red clays for the making of seed balls. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.
TALC (3MgO · 4SiO2 · H2O): Magnesium silicate, soap stone. It is a source of the flux magnesium oxide in glazes and clay bodies, is less likely to cause glaze bubbles (pin holing), can promote matte surfaces and opacity in low fire glazes and in stoneware bodies it is used to increase resistance to thermal shock. Used in slip casting bodies in proportions up to 50% and up to 60% in low fire bodies to increase thermal expansion and help them fit commercial glazes better. Acute effect: Mild irritant. Chronic effect: May be hazardous over long term due to silicosis.