Clay selection is the foundation to achieve desired output in the final product

The three most commonly used clay products are earthenware, mid/high-fire stoneware and porcelain. Clays come in white, off white, grey and dark colours such as Terra Cotta.

To choose the right clay type for any application, one needs to consider the following factors.

• The type/purpose of the end product
• Production technique adopted
• Type of kiln used for firing the clay
• Skill level of available manpower
• Cost

Over the years Potters worldwide have been digging and processing clay for various uses and have gained great knowledge in selecting the right clay from these experiences. At Alfa Clayworks we select the best combination of clay that closely suit our customer’ requirements well.

CLAY PREPARATION

Well prepared clay is easy to work with and ensures best product quality.

SOAKING AND CLEANING

Clay preparation starts with soaking clay in large water tanks to remove soil particles and other naturally found impurities.

FILTERING AND DRYING

Purified clay is in the form of thick slurry. The slurry is filter pressed to force out excess water and left to dry. The resultant clay is thick and rather dry, with about 20% water and is called cake now.

PUGGING / WEDGING

The cake is put into a ‘pug mill’ where it is chopped into fine pieces to de-air the clay. When potters prefer do it by hand it is called wedging.

FORMING

The best method to achieve the desired result is based on the product and its use.

HAND-BUILDING

This is the earliest forming method. Clayware can be made by hand from coils of clay, combining flat slabs of clay, pinching solid balls of clay or a combination of these.

THE POTTER’S WHEEL

Prepared clay is placed in the centre of a potter’s wheel, known as a wheel-head, which the potter rotates with a stick or with a variable-speed electric motor. This process is called ‘throwing’. During this process, the wheel rotates while the solid ball of soft clay is pressed, squeezed and pulled gently upwards and outwards into a hollow shape.

SCULPTING

Certain critical figurines or unique designs can only be achieved by sculpting techniques.

GRANULATE PRESSING

Here, pottery is shaped by pressing clay in a semi-dry and granulated condition into a mould with the help of a porous die through which water is pumped at high pressure.

SLIP CASTING

A pourable slip or slurry is poured into a two-part plaster mould. The excess is poured out, and the slip is permitted to stiffen and dry. The plaster mould sucks up some of the excess water and helps hasten the drying process.

AIR DRYING

It takes a little patience to dry formed wet pieces, but it’s worth the wait.

After Forming, pieces created should be placed on the drying shelves in a damp room. After the pieces have dried for a minimum of 48 hours in the damp room, they will reach a stage of partial dryness, referred to as Leather hard. It is then hand-finished and decorated if required. These pieces are set out to dry again, until they are now fully dry and ready for Firing. When a piece of pottery has dried completely it is referred to as a piece of Green ware.

FIRING

First came the Earth, then the Water, the Wind and now its Fire. All forces of nature work for you.

BISQUE FIRING

Dried Green ware that is to be ‘Glazed’, is loaded into Kilns for the first of two firings. Firing happens at approximately 1800 Degrees Fahrenheit and hardens the ware, making it easier to handle without breaking during the glazing process. At this stage clay retains its porosity. The liquid part of glaze is absorbed by the porous bisque ware and the glassy materials in the glaze are left deposited on the surface of the bisque ware. So, the bisque process is simply done to make glazing easier.

FIRING

Firing of pottery is done using a variety of methods, with a kiln being the usual firing method. Kilns may be heated by firewood, gas, coal, or electricity. Finished and dried pieces are loaded into kilns and fired between 5 to 8 hours based on the type of kiln used and the product requirements.

Kiln firing completely dehydrates and burns off all organic/inorganic materials, melts and vitrifies the formed clay pieces into a finished product fit for use.

In case of glazed pieces, the kiln changes the glaze into a glass-like coating, which helps to make the pot virtually impervious to liquid. Once out of the kiln, the unglazed foot (or bottom) of the pottery is polished on a machine with a cleaning pad. The piece is packed and ready to be shipped out for sale.

GLAZING

The glaze is a mixture of ground glass, clays, colouring materials and water and is applied to the bisque pot by dipping, pouring, spraying, brushing, sponging or a combination of some of these techniques.

PAINTING & DECORATION

When absolutely dry, Clayware turns from dark grey to light grey; almost white. They are then either hand painted or spray painted depending on the size and end use.

Clayware can be made beautiful and attractive by also using methods such as Lithography (used to apply designs to articles), Banding (application of a band of colour on the edge of the clayware, by the Potter), Glazing (applying a glassy coating on pottery) and a host of other methods.

QUALITY CONTROL

Modern Clayware production incorporates various quality control methods at different stages in the production process to ascertain aspects like purity and composition of the material in order to ensure consistency in the quality of the end product, the well-being of those involved in production and also the health of the end user.