China clay. Features and components.

For the composition of ceramic paste in addition to kaolin china clay used secondary.

Common features:
be very plastic.
porous texture.
The color varies according to their composition, between gray and white or ivory.

cooking temperature is between 1200 º 1,300 º C, so it belongs to the clays that melt at high temperatures.

Around the world, there are countless types of this clay, although in few cases the material as found in nature will be fully satisfactory, it will be necessary to treat them.
To vary the degree of fusion and plasticity is added feldspar and ball clay.

For pasta dishes requires the presence of lime. The white paste china, is a mixture of calcined flint fire clay and carbonate of lime, which is added potash and soda.
With clay, feldspar and kaolin are used, making cake baking at a temperature above the deck or enamel, usually 1200 º, 1300 º. A good slab should be hard, loud, white and porous.

Being a compact clay with a good ability to melt and showing a high density and good when cooked predisponibilidad to apply the glazes have made these types of clay one of the most prized by potters.

There are some ways to make pasta dishes decreasing its firing temperature around 1100 º, for example using the mixture of 70% fireclay and 30% silica.

The Loza decks must have a main feature, which is totally transparent cover and clear, with a perfect glaze, suits and cover with the colors used in its decoration. Usually consist of a base to fry that is added kaolin and carbonate of lead, although this last component is toxic and is now obsolete.

Cover borax:
The deck consists of borax: 10% silica, 20% feldspar, 15% kaolin, 15% chalk and 40% of borax.

From the thirteenth century to the fifteenth century, the golden dishes of Islamic origin in ceramics became typical of Spain.
In central Europe in the sixteenth and seventeenth centuries were very successful lead glazes on pottery imitating metal jugs of beer. The traditional English earthenware was decorated with slip and glaze of lead, like pottery used by the European peasants and introduced it in America.

In Italy and Germany, clay pottery with tin glaze is known as “majolica” the island of Mallorca, where, until the fourteenth century, was produced in large quantities.