Specifically what is clay?
Clay surfaces is a mineral removed from the ground that can be readily moulded like plasticine. At microscopic level, the particles of clay have a flat plate-like framework providing them with this plastic like property. The 2 most common clays are Ball Clay and China Clay (Kaolin). pottery class san jose
What is a clay body?
The conditions clay and body are being used by potters almost interchangeably. In most cases it is not technically correct! A body is a formula that contain clay and other mineral deposits. Therefore clay is a raw material element of a body. In no technical conditions the clay surfaces body can be considered to be the key part of the pottery before it is shaped, glazed and decorated.
In customs a body was just a clay dug from the ground that was variable in both its composition and properties. Nevertheless , modern commercial potters no more rely on bodies created from clay surfaces alone. To accomplish specific properties they are created in a very precise way.
An array of raw clays and minerals are being used from all around the world. They will vary in colour, power, particle size as well as mineralogy and chastity. No two clays from different parts of the world are precisely the same although for assessment purposes they can action in a similar fashion when used as part of a body formula
Range of Clay surfaces Bodies
The are numerous clay bodies produced commercial around the world available to the craft knitter, studio potter and commercial pottery. Indeed there are so many that it is impossible to fine detail them all here. Furthermore many commercial potteries produce their own clay body according their own unique recipe.
Bodies are often also developed to make them suited to the development process. Therefore suppliers often state which bodies are more suited to hand tossing, casting, hand building and so forth.
Clay bodies however can be classified into a relatively small number of categories according to their colour, firing range and texture.
This kind of is a smooth uneven extremely white firing body that is also clear. It is unique in that it includes a high proportion of calcined bone ash and biscuit shoots at approx 1220C.
This is an easy textured translucent white shooting body. Two types of porcelain are created, a ‘hard porcelain’ firing to in excess of 1400C and a ‘soft porcelain’ shooting to approx 1250C.
This class of clay-based body is commonly employed by craft and studio potters. Excellent relatively high statuette firing teperature of 1250-1300C and is also available in a range of colours and textures, from white to buff. By glazing with a reactive type girl glaze a range of effects and colours can be performed.
This allows the craft potter to find an appealing coloring and texture to make his unique wares.
This class of body is typified by the unique red terracotta shade. It has a high Iron content which offers the unique colour. Just like stoneware the smooth consistency can be modified, by addition of grog (coarse material), to give a much rougher finish.
This type of person is often used for hand painting by enthusiasts. The body is straightforward statuette fired to approx 1000C to allow easy combing of underglaze colours or coloured glaze followed by a glaze firing to 1050C to 1150C.. Physique colour ranges from white to buff. Some body can even be grogged to provide texture. Optimum body durability is achieved by heating 1180-1220C but this summit is seldom needed for decorative only ware.
This variety of physiques include, highly coloured physiques, low firing bodies, Raku bodies and special highly textured bodies. In the matter of Raku the body is altered to allow rapid heating system and cooling without great, usually by digging in grog.