Category: Tiles and Ceramic Materials

Stoneware are the products manufactured from refractory clay mixed with crushed pottery, powdered stone, etc. The clay is prepared carefully and moulded to the required shape. The stoneware is then dried under the shade to prevent any cracking or deformation of the product. The dried material is burnt in a kiln, gradually heating to a…

Porcelainware or merely porcelain indicates fine earthenware, which is white, thin and transparent. It is also sometimes called whiteware. It is basically prepared from clay and mixed with feldspar, quartz and minerals. The ingredients are powdered and thoroughly mixed. The mixture is moulded to the required shape and then burnt. Porcelain has various uses. In…

The dried objects are then burnt in special muffle furnaces. A typical muffle furnace is shown in Fig. 4.3. A muffle furnace has the provision to heat the product without coming into contact with fuels. In order to regulate the drought a damper is provided at the side of the furnace. Figure 4.3 Muffle furnace to…

The terra-cotta is allowed to dry in the mould for some days, and then the object in the terra-cotta mould is taken out and then allowed in a room or shed for drying. Gradual drying is to be done failing which the shape of the object may get changed or cracked.

Apart from wooden moulds, special moulds of plaster of Paris or templates of zinc are used. Fine sand is sprinkled on the inside surface of the mould and the clay is then pressed in the mould with the hand.

The clay selected for terra-cotta should contain about 5–8% of iron oxide and about 1% of lime. Sometimes clay with high alumina content is used. To these selected clays, sand, ground glass, old terra-cotta or pottery are added. The addition of these materials provides strength and rigidity to the terra-cotta and also prevents shrinking while…

Terra-cotta is earthenware of vitrified material. It is high-quality earthenware. It is used as a substitute for stone in the ornamentation of buildings. The manufacture of terra-cotta involves the same four stages as that of tiles.

It has been discussed that earthenware is manufactured from ordinary clay burnt at low temperatures. Sometimes the clay is mixed with sand, crushed pottery, etc. Earthenware are susceptible to damage by atmospheric action since they are soft and porous. In general, they should not absorb more than about 20% of water by weight. In order…

The tiles are burnt in a kiln which could accommodate 30,000–40,000 tiles. Such kilns are partly underground and are usually provided with a roof to protect the kiln from rain. A layer of bricks is laid over the long narrow flues, and the flues are fed with wood. The bricks are so placed such that…

After two days of moulding, they are slightly beaten with a flat wooden mallet to correct the irregularity in shape due to warping. They are then kept on edges for further drying under shade for 2 days. This is done to prevent warping and cracking.