CeramicsCeramicsThe word ceramic, derives its name The word ceramic, derives its name from the Greek from the Greek keramoskeramos, meaning , meaning

"pottery", which in turn is derived from "pottery", which in turn is derived from an older Sanskrit root, meaning "to an older Sanskrit root, meaning "to burn". The Greeks used the term to burn". The Greeks used the term to

mean "burnt stuff" or "burned earth". mean "burnt stuff" or "burned earth".

What is Clay?What is Clay?

ClayClay

Clay is made up of Silica, Clay is made up of Silica, Aluminum Oxides, and Aluminum Oxides, and water.water.

Generally Clay is formed Generally Clay is formed by the chemical by the chemical weathering of silicate-weathering of silicate-bearing rocks by carbonic bearing rocks by carbonic acids.acids.

Clay particles are Clay particles are distinguished from other distinguished from other particles in soil by their particles in soil by their small size, plasticity, and small size, plasticity, and affinity for water.affinity for water.

particles of decomposed rock combined with water to particles of decomposed rock combined with water to create a plastic, malleable body which is then fired in create a plastic, malleable body which is then fired in a kiln to fuse the particles back into a stone-like state. a kiln to fuse the particles back into a stone-like state.

CulturesCultures Archaeologists have Archaeologists have

uncovered human-made uncovered human-made ceramics that date back to ceramics that date back to at least 24,000 BC. These at least 24,000 BC. These ceramics were found in ceramics were found in what was formerly what was formerly Czechoslovakia and were Czechoslovakia and were in the form of animal and in the form of animal and human figurines.human figurines.

The first use of functional The first use of functional pottery vessels is thought pottery vessels is thought to be in 9,000 BC. These to be in 9,000 BC. These vessels were most likely vessels were most likely used to hold and store used to hold and store grain and other foods grain and other foods

UsesUses Most people, when they hear the Most people, when they hear the

word ceramics, think of art, word ceramics, think of art, dinnerware, pottery, tiles, brick and dinnerware, pottery, tiles, brick and toilets. The above mentioned toilets. The above mentioned products are commonly referred to products are commonly referred to as traditional or silicate-based as traditional or silicate-based ceramics. ceramics.

What most people aren't aware What most people aren't aware of is how diverse ceramic of is how diverse ceramic materials really are. They can materials really are. They can be used for almost anything. be used for almost anything. Ceramics are currently used for Ceramics are currently used for computers, tools, dental computers, tools, dental replacements, engine parts and replacements, engine parts and tiles on space shuttles. tiles on space shuttles. Ceramics play an important role Ceramics play an important role in our everyday lives, even the in our everyday lives, even the parts we can't see and don't parts we can't see and don't give much thought to.give much thought to.

Types of ClayTypes of Clay

EarthenwareEarthenware -A low-fire -A low-fire porous body, usually red or porous body, usually red or orange-tan in color due to the orange-tan in color due to the impurities and presence of impurities and presence of iron. It is the most widely iron. It is the most widely available type worldwide. available type worldwide.

Types of clayTypes of clay Stoneware -A high Stoneware -A high

temperature, strong, vitreous temperature, strong, vitreous body, usually gray-brown in body, usually gray-brown in color. It is the most popular color. It is the most popular clay for utilitarian wares. clay for utilitarian wares.

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Types of ClayTypes of Clay

Porcelain- The Porcelain- The highest temperature highest temperature as well and most as well and most temperamental clay temperamental clay body. It is the body. It is the purest form of clay purest form of clay possible, it is white possible, it is white and has translucent and has translucent capabilities. capabilities.

GreenwareGreenware GreenwareGreenware is a is a

term used to term used to describe clay describe clay that has not that has not been fired yet.been fired yet.

Stages of ClayStages of Clay

Clay mixed with water, until it is like Clay mixed with water, until it is like mud is called mud is called SlipSlip

When clay is soft and pliable it is When clay is soft and pliable it is called called Plastic.Plastic.

When the clay is still workable on the When the clay is still workable on the surface it is called surface it is called Leather HardLeather Hard..

Bone DryBone Dry is the stage at which the is the stage at which the clay is completely dry, fragile, and is clay is completely dry, fragile, and is ready to be fired.ready to be fired.

Slip -A thick and creamy mixture of Slip -A thick and creamy mixture of clay and water used to join clay parts clay and water used to join clay parts together or to decorate the surface. It together or to decorate the surface. It is applied before firing, when the clay is applied before firing, when the clay is still wet. is still wet.

Plastic-Clay that is soft, pliable and Plastic-Clay that is soft, pliable and easy to work with. easy to work with.

Leatherhard-Clay that has been Leatherhard-Clay that has been allowed to dry slightly, making it allowed to dry slightly, making it stiffer and able to support its weight, stiffer and able to support its weight, but can still be worked on and have but can still be worked on and have parts attached. parts attached.

Bone Dry-The state of clay when all Bone Dry-The state of clay when all naturally occurring water has naturally occurring water has evaporated. The clay is hard, dry, evaporated. The clay is hard, dry, with a chalk like consistency. with a chalk like consistency.

KilnKiln When the clay is Bone When the clay is Bone

Dry it is ready for its Dry it is ready for its first firing which first firing which subjects the clay to high subjects the clay to high temperatures and temperatures and causes a chemical causes a chemical reaction.reaction.

A fireplace or oven A fireplace or oven specifically designed for specifically designed for hardening clay is called hardening clay is called a a KilnKiln..

Kilns come in all sizes Kilns come in all sizes and shapes from wood and shapes from wood fired pits dug in the fired pits dug in the ground to computerized ground to computerized containers like the one containers like the one on the left. on the left.

Bisque-The first firing for the clay, Bisque-The first firing for the clay, removes all of the water, (both actual and removes all of the water, (both actual and chemical) and carbon, The fusing of the chemical) and carbon, The fusing of the particles has begun, yet the clay is still particles has begun, yet the clay is still porous to allow for glaze absorption. It porous to allow for glaze absorption. It can no longer be slaked down and can no longer be slaked down and recycled. recycled.

Glazeware-The second firing of the clay Glazeware-The second firing of the clay with a coating of glaze upon its surface, it with a coating of glaze upon its surface, it is fired to a higher temperature than is fired to a higher temperature than bisque and therefore fuses the particles bisque and therefore fuses the particles into a solid, non-porous state called into a solid, non-porous state called vitrtification. vitrtification.

Until the clay has been fired it is Until the clay has been fired it is possible to RECYCLE the hardened possible to RECYCLE the hardened clay so it can be reused.clay so it can be reused.

All clay used in class should be All clay used in class should be recycled if it is not going to be fired.recycled if it is not going to be fired.

DO NOT THROW CLAY INTO DO NOT THROW CLAY INTO GARBAGE CANS!GARBAGE CANS!

BisqueBisque BisqueBisque is the term is the term

given to the first given to the first firing of clay. firing of clay.

ConesCones (left) are (left) are used to determine used to determine what temperature what temperature the clay is fired at. the clay is fired at.

Pyrometric cone Pyrometric cone chartchart

06 1798°F

05-1/2 1839°F

05 1870°F

04 1915°F

03 1960°F

02 1972°F

01 1999°F

1 2028°F

2 2034°F

3 2039°F

4 2086°F

5 2118°F

5-1/2 2133°F

6 2165°F

7 2194°F

8 2212°F

9 2235°F

10 2284°F

 

GlazeGlaze Glaze is a powdery material Glaze is a powdery material

that is coated on Ceramics that is coated on Ceramics and then fired to form a thin and then fired to form a thin glass like coating.glass like coating.

Glazing not only creates an Glazing not only creates an aesthetic smooth, surface aesthetic smooth, surface but also strengthens the but also strengthens the piece and allows it to hold piece and allows it to hold liquid. liquid.

It is possible to enhance the It is possible to enhance the surface of the clay through surface of the clay through the use of glazes and under the use of glazes and under glazes.glazes.

HAZARDSHAZARDS

Clay Dust can be hazardous if inhaled Clay Dust can be hazardous if inhaled over a long period of time.over a long period of time.

Although students are at minimal risk Although students are at minimal risk due to the limited exposure, care due to the limited exposure, care should be taken to minimize dust in should be taken to minimize dust in the classroom.the classroom.

Clean all tables and tools with wet Clean all tables and tools with wet sponges, and dispose of dried clay sponges, and dispose of dried clay properly. (recycle bucket)properly. (recycle bucket)

NEVER sand pots in the classroom.NEVER sand pots in the classroom.

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