A PowerPoint presentation about clay - the three types/classification of clay, the stages of clay before and after firing and other key terms used in ceramics

1. WHAT IS CERAMICS?
Working with Clay:
By Bernard E. Richardson | Master Teacher & Visual Arts Educator | 2022
© Bernard E. Richardson | 2022

2. • Clay is a product made from earth and water and when heated it
becomes hard.
WHAT IS CLAY?
• It is made up of very thin soil particles which becomes plastic when
wet and very hard when dry.
Plasticity: when the tiny soil particles are wet and stick together so
that the clay can be molded (shaped by hand).

3. WHAT IS CERAMICS?
• Ceramics is the general term for clay objects that have been fired to
change it to a permanent hardened state.

4. TYPES OF CLAY
• There are three (3) classifications of Clay
1. Earthenware
2. Stoneware
3. Porcelain

5. • It is soft and relatively smooth.
• Has large particles, porous and not waterproof.
• It must be glazed in order to be waterproof.
EARTHENWARE CLAY
TEXTURE
FIRING
• It is bisque (biscuit) fired between 1000 and 1150˚C (1830 - 2100˚F).
• It is glazed fired at temperature between 1040 to 1160˚C (1900 - 2120˚F).
• Has a reddish-brown or black colour after firing.
• Traditionally used for domestic items such as pots and vases.

6. • It is hard and rough.
• Has small particles, less porous and is waterproof and airtight.
• It can be glazed to enhance the finish.
STONEWAREWARE CLAY
TEXTURE
FIRING
• It is bisque (biscuit) fired between 1000˚C (1830˚F)
• It is glazed fired at temperature between 1200 to 1300˚C
(2190 - 2370˚F)
• After firing the clay is opaque and colour may be brown or
light to dark grey.
• Traditionally used for industrial ceramics – making of kitchenware such as plates,
bowls and cookware (ceramic pots).

7. • It is very smooth and brittle which means it breaks easily.
• Has very small particles (extremely fine clay), and the clay is
less dense and porous.
• It is waterproof and airtight.
• It must be glazed in order to be waterproof.
PORCELAIN CLAY
TEXTURE
FIRING
• It is bisque (biscuit) fired at 1000˚C (1830˚F)
• It is glazed fired between 1240 to 1300˚C (2260 - 2370˚F)
• After firing it is translucent and is white or pale grey in colour.
Sometimes it is pale blue to green in colour.
• Known as china and has an almost glass-like finish.
• Used for fine ware and decorative ceramic ornaments.

8. STAGES OF CLAY before firing
• Clay is wet and at a workable stage (best for molding, construction
and recycling).
• Can be joined to other pieces.
• Clay is stiff and will hold its shape.
• Still can be joined to other pieces.
• Best stage for carving into,
smoothing and still can be recycled.
• The clay is completely dry but
unfired.
• It is fragile and cannot be
moulded
• Clay is ready to be fired
1. PLASTIC / WET:
2a. LEATHER HARD
2. GREENWARE: • Unfired clay objects.
• There are two (2) types:
2b. BONE DRY

9. STAGES OF CLAY after firing
1. BISQUEWARE: • Clay that has been fired ONCE at a relatively
low temperature in the kiln.
2. GLAZEWARE: • Clay that has been fired TWO times.
• The clay is painted with a glaze and fired a
second time at a very high temperature.
• The glaze forms a coating of glass onto the
surface.

10. Some Basic CERAMIC TERMS
• CERAMICS - Clay objects that have been fired and changed
to a permanent hardened state to retain their shape.
• POTTERY – Functional ceramic objects such as vases, pots, bowls or
plates shaped from moist clay and fired.
• WEDGING – This is the process of removing air bubbles (that
would cause the clay to explode in the kiln) from the clay. The
clay is kneaded like bread dough to twist out or pop the air
bubbles

11. • FIRING – Is the process of heating or ‘baking’ the clay at high
temperatures changing it from soft clay into a permanent
hardened state(ceramics).
• KILN – A structure built for baking the clay at high
temperatures
• SLIP – is also known as the Potter’s glue. It is watered down/
liquified clay which is used to attach one piece of clay to
another.
• SCORING – A method of connecting or joining two pieces of
clay together. Using a pointed tool, scratch into the two
surfaces that are to be joined. Apply some slip to both with
your fingers and then press together to stick them together.

12. CLAY
TOOLS

13. • Billington, Dora (revised by Colbeck, John). 1983. The technique of pottery.
London: B T Batsford Limited
• Christy, Geraldine & Pearch, Sarah. 1992. Step by step art school ceramics.
London: Hamlyn.
• Sieupersad, Allan. 2009. Longman visual arts for secondary schools. Essex:
Pearson Education Limited.
RESOURCES
BOOKS

14. • https://images.ctfassets.net/f1fikihmjtrp/CJFeUpMpOQkenXgTZy2S2/992cb213f03003cd28cbbd71f96bfbe8
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• https://www.enasco.com/medias/8300160-main-
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• https://www.enasco.com/medias/4300128-main-
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• https://i-deals.net/wp-content/uploads/2020/07/71Dhh9nigHL._AC_SL1500_.jpg
• https://d1idmtl6fikohh.cloudfront.net/image/cache/catalog/clay/clay_block_porcelain-700x700.jpg
• https://live.staticflickr.com/65535/48529776937_ecbd192a19_b.jpg
• http://hsceramics.weebly.com/uploads/2/6/0/3/26032053/5845892.jpg
• http://swfineart.weebly.com/uploads/2/4/6/3/24632159/published/bisqueware.jpeg?1519862267
• https://i.pinimg.com/236x/87/b4/62/87b4620162a1b92530ae9964a0069e94--pottery-tools-craft-
tutorials.jpg
IMAGE COURTESIES

15. THE END