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The potters wheel and kiln, beginning ceramics

The potters wheel and kiln, beginning ceramics
The plastic properties of clay have been known to man in ancient times. She myalas easily and quickly took a form under the skillful hands, which were very difficult or even impossible to give other known materials. It was also found that the pottery after firing them into the fire miraculously change their properties - hardness acquire stone, water resistance and fire resistance. All this has made the clay most convenient raw material for the manufacture of tableware and kitchen utensils.
Like all crafts, ceramics machinery has come a long and difficult path. Millennium went to study the advantages and disadvantages of various clays. Of the many types of ancient masters learned to choose those that have the highest plasticity, connectivity and capacity. In the clay mass began to mix various additives that improve the quality of products (for example, large or fine sand). At the same time the ancient potters mastered various methods of modeling. Give a piece of raw clay jug form, or at least a simple pot was not easy. Usually, the potter took a lump of clay, by squeezing its middle part and careful squeezing the sides of the bottom fashioned. Then, the bottom edge of the master began to stick unrolled strips of clay and so gradually got wall. In the end, leaving a rough vessel suitable after burning on a fire to cook food in it.

An important step in the development of the pottery industry was the development of receiving rotation. In this case, the master clings to the bottom of the finished piece of clay and turning the bottom of the left hand, right-hand traced a piece of a spiral, gradually fashioning faces pot. In this method, the product was more smooth. Later, for the convenience of a billet steel underlay wooden disc. Then he came to the conclusion that the modeling process much easier should make this disc to rotate with the workpiece - as was invented by a simple manual potter's wheel. It was a disc in the middle depth about half its thickness. His deepening disc is placed on speaking and more rounded end of a wooden rod firmly strengthened in the ground. To stem not staggered and held upright, between him and the circle was placed a fixed wooden board with a hole in the middle. Get a good prilazhennoy device. With one hand, the master brought round to smooth uniform rotation, and the other started sculpting. This simple device made a real revolution in pottery, raising it to the level of art. Through his work significantly accelerate and improve. When you rotate the product came out much more dense and homogeneous. They get the right shape and elegant.

A new step towards improving the art of pottery was the invention of the foot circle, which came into use in the 2nd millennium BC Its main advantage is that it has allowed to increase the rotation speed of the master and released to work with both hands. The main differences between the new terms were as follows. The spindle (rotation axis) has been lengthened. The rotating disk was rigidly connected thereto. To strengthen the spindle served two boards. Lower was the foundation of the whole device (it was undercut, where to insert the end of the spindle). The top board with a through hole in the spindle is supported vertically. Finally, the lower part of the spindle was rigidly attached wheel-operated. Sitting close to the circle potter drew a foot in the lower circle and brought it to the smooth movement. Due to the fact that the lower wheel was heavier and larger in diameter than the working top, it served as the flywheel: keep rotating for a while and after a foot from it has been removed.

Along with the improvement of the potter's wheel went complication art of clay baking. In ancient times, the firing was carried out directly on an open flame at a temperature of 300-400 degrees. Later, he began to produce in special furnaces. Already the first primitive furnace allowed to double the heating temperature. Particles of clay are better to fuse with each other, the strength of products increased markedly. In place of the old walled vessels come filled with a thin eggshell walls (up to 3 mm). The invention of furnaces of great significance for the history of technology, as was the beginning of the construction of high-temperature devices, received then spread to other sectors of the economy (especially in the steel industry). The oven was made as follows: from thin trunks made wooden frame, which is coated with a thick layer of clay, leaving only small holes in some places. This frame placed above the recess, which is a place to fuel the fire. From a strong fire burned the wooden parts, and the clay is calcined and formed a tight holes. When firing a furnace wall, and red-hot and also began to radiate heat. Due to the heat concentration within the furnace temperature it can rise up to 800 and even up to 900 degrees.

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