ceramic , use of ceramic, types of ceramics, ceramic nameplates, tiles, pottery, Murals for interiors & exteriors of home and corporate offices

Ceramics

The word ceramic can be traced back to the Greek term keramos, meaning "a potter" or "pottery." Keramos in turn is related to an older Sanskrit root meaning "to burn."

Pottery is one of the oldest crafts more than 10,000 years old, which archaeologists have used to carve out the history of civilizations. In ancient archeological sites remains of pottery, toys, vessels, primitive deities etc. have been discovered.

Essentially, ceramics is the art of making functional and art objects from clay. Clay is simply formless material abundantly available on the earth;s surface. In its natural state clay is pliable, but becomes hard and durable when exposed to high temperatures.
It is the potter, who by shaping and processing, changes this clay into objects of utility and beauty.

The art is centuries old and yet even today working with clay and firing it remains a challenge. The different techniques of forming, glazing and firing bring forth results that can produce thrill or pangs of disappointment.

Uses of ceramics

Ceramics can be used for industrial, commercial or art purposes.

Industrial ceramics is about the use of ceramics to develop ceramic materials with special properties such as heat resistance, hardness, electrical conductance, etc., to build industrial and scientific components.

Commercial ceramics includes the use of ceramics to manufacture everyday products using ceramic materials, e.g. sanitary-ware, wall and floor tiles, etc.

Ceramics can also be an art form that provides relaxation and the ability to be creative.

Types of Ceramics

Terra-cotta	850-1000 ⁰C	The organic content of the clay defines the temperature it must be fired at vitrification, which in urn decides the type of resultant pottery
Earthenware	1000-1150 ⁰C	(Very porous and mostly commonly used. Eg. Water pots, bricks, roofing tiles etc.)
Stone-ware	1150 - 1300 ⁰C	(semi-porous glazed and unglazed pottery used for commercial crockery and tiles)
Porcelain	1300-1400 ⁰C	(Fully vitrified, impervious to liquids and acids. Used for more durable industrial and commercial use. Ceramic artists have a great affinity to stone ware pottery. All ADIPA Ceramics products are stoneware category)
High-tech Ceramics (Used for industrial components)	1400⁰C and above	(Virtually transparent with a very refined physicall apperance. Some of the most famous porcelain art ware originated in China)

The Process - Each step in the overall pottery process, is an art in it's self.

The craft of ceramics depends on the exploitation of several intrinsic qualities of clay--its plasticity, its ability to hold the shape into which it is formed as it dries, and the fact that heating it to maturity transforms it into a new permanently hard substance.

The Raw Material - Clay

The first step is locating and preparing a suitable deposit of clay body. Clay is a common name for fine-grained, earthy materials that become plastic when wet. The other properties that must be taken into consideration are shrinkage during drying and firing, fineness of grain and color, texture and hardness after firing.

Preparing the Clay
Once a suitable deposit of clay is located it is collected, cleaned, washed, thoroughly mixed and wedged. Wedging is the process of kneeding and mixing the clay to make it pliable. It makes the clay homogenous and removes all air bubbles. This is particularly important, as the presence of air bubbles in the clay will result in explosions in the kiln as the air pockets expand and burst.

Molding the Clay

This prepared clay in now ready to be formed into deirable shapes and forms by various methods such as:

Hand Building -

	Slab and Coil work
	Pinching and Coil Work

Potters Wheel

Slip casting and plaster molds

Die pressed tile work

Drying

Once the clayed if formed or designed it is slowly dried for a few days in a damp room or in plastic sheets to prevent cracking and warpage due to shrinkage. It is dried till it reaches a stage of partial hardness, which is referred to as leatherhard.

This stage of drying is characterized by a loss of water through evaporation that results in the clay's stiffening and losing some flexibility.

This is an excellent time to refine the piece - carving off excess clay, adding handles or decorative elements, trimming the foot-ring of a bowl, etc.

Green ware
	When a piece of pottery has dried completely it is referred to as greenware. This means it has lost all the physical content of water through evaporation and has no flexibility. You cannot bend it, add anything to it, or carve anything from it. You cannot do anything to it except break it!
This is purely a passive state for the clay awaiting the first firing. At this stage the clay forms can still be broken and re-prepared into a plastic lump of clay - there has been no permanent transformation in the chemical composition of the clay yet!

Bisque Firing

Greenware is now loaded into the kilns for the first of two firings, known as the bisque firing.

The purpose of the Bisque firing is to remove the physical and chemical content of water from the clay by reaching a temperature of around 1000DC.

The bisque process is done to make handling of ware easier during the glazing process. The bisque also makes them porous, which lets the glaze soak into the clay, later forming the interface layer between the clay body and the fired glaze.

	During the Bisque firing there are 2 very critical stages:
	The first stage is reached at around 100DC centigrade when the physical water content begines to boil and evaporate.
	The second stage is anywhere around 500 -600 DC when chemically combined water from the clay is lost. This is also a stage where the quartz inversion (change in formation of silica molecules) in the clay takes place.

During both these stages the firing has to be done very slowly and cautiously. Fast firing can easily cause the work to explode!

Once cooled the kiln is opened and the bisque ware is ready to be glazed.

Glazing
The glazing process and firing techniques, affect the finished piece, as much as the forming process. Glazes are thin layers of glass fused into the surface of the ceramic ware. The glaze is a mixture of ground glass, clays, coloring oxides and water. It is applied to the bisqued pot by dipping, pouring, spraying, brushing, sponging, or a combination of these techniques. Glazing makes the pottery more beautiful, impervious, mechanically stronger, resistant to scratching, and chemically more inert.
Through much experimentation it was discovered by potters, that certain oxides produced certain types of effects on a given piece of pottery. For a glaze to fuse with a given piece of pottery, the glaze must have certain elements, which vitrify and are tolerant to the heat of the firing. These elements, known as flux, all fire at different times and temperatures, but make the glaze adhere to the clay body, as well as create the glassy appearance of most stone and porcelain clay bodies. Without a flux and certain other elements in a glaze, the glaze drips off of the clay body at high temperatures and doesn't adhere.

Glaze Firing

The glaze firing is the second of the two firings and is fired to the higher vitrification temperatures of the clay body. For ADIPA Ceramic Stone ware the glaze firing reaches a temperature of approximately 1250-1300 DC.

When the Glaze firing is complete, the ceramic pieces have lost as much as 12% or their original volume.

The glazes react with the clay body through heat reductions, oxidations and other chemical reactions that take place inside the kiln and this is what you see on a finished piece of pottery.

Overglaze Firing

Sometimes a third firing is done at low temperatures of 500-700DC to add more decorative lustres and colors to a glazed piece. This is the known as the over-glaze technique.

These are, loosely speaking, very low fire glazes that are melted atop the previously fired high temperature glaze. At this low temperature, the underlying glaze does not even melt, instead the luster, china paint, or decal, melt onto the glaze.

This technique is more decorative and less durable. Abrasion can erode this coating and eventually, the overglaze will be gone or muted by time. Still, unusual and exotic effects are possible, and for this reason, potters are interested in this area. Some techniques, like china painting, often involve multiple overglaze firings, layering one color on top of another as complicated designs emerge

Links

	Terra-Cotta
	Salt-Glazing
	Raku
	Cold-Ceramics

The Artist || Name Boards || Ceramic Tiles || Studio Pottery || Tile Products || Contact Us || Home