Clay
CLAY
WHAT IS CLAY?
Clay is a type of fine-grained natural soil material containing clay minerals. Clays develop plasticity when wet, due to a molecular film of water surrounding the clay particles, but become hard, brittle and non–plastic upon drying or firing. Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide.
Clay is the oldest known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery. Some of the earliest pottery shards have been dated to around 14,000 BC, and clay tablets were the first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtering. Between one-half and two-thirds of the world's population live or work in buildings made with clay, often baked into brick, as an essential part of its load-bearing structure.
PROPERTIES OF CLAY:
- Small Particle Size. Clay soils have small particles.
- Low Workability.
- Affinity for Water. Clay minerals all have a great affinity for water.
- Fertility. Water isn't the only substance clay holds.
- Improvability.
Coiling is a primary forming technique, meaning that it is used to produce the overall shape of a vessel that is then refined by other techniques. Coiling involves the rolling out of clay into a long thin sausage-like form that is wound round like a spring. Building a vessel with coils is accomplished by placing them around the circumference and gradually increasing the height. The diagram below shows what a coiled pot appears like before it is refined. The most common coiled vessel shape have either round or pointed bases. Pieces can also be identified by step-like fractures occurring through the piece.
PRODUCT PROCESS:
Raw Materials:-
- Clay
- Water
- Slurry
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