How to Overcome Test Results

Ideal plasticity clay is clay that has dried shrinkage percentage between 5% s / d 8%. When the dry shrinkage test result is below the average of 5%, meaning less clay tested hard plastic so it is likely to be formed. To overcome this, it should be added that a plastic material such as bentonite ballclay or as needed.

Conversely, if the test results of the average dry shrinkage above 8%, meaning that the tested clay too hard plastic so it is likely to be formed in the drying and cracking. To fix this, do not need to be added to plastic materials such as grog or quartz to reduce drying shrinkage and reduce the tendency to crack. If the shrinkage of the clay is too big and too fast drying process, will cause cracking or deformation.

Clay Body Temperature Testing Maturity
Testing maturity burning objects out of clay is one of the important activities. It is necessary to know how high the temperature of the maturity of a mass of clay types of natural and artificial clay is a mixture of some of the clay material.

The definition of a mature temperature is the temperature at which objects are burned undergo vitrification process, so that the content of free silica in the clay body mass begin to melt / menggelas and fused the results or the whole cavity partially filled pores. In the cooling process, which has undergone vitrification times become hard, dense and impermeable.

Maturity level regarding hardness, density, water absorption or keporian and power losses for each type of good clay pottery (Earthenware), stoneware or porcelain vary, as described below:

Clay pottery types have matured temperatures between 9500C-11500C, with the physical properties of porous, water absorption power between 1.5% -13%, somewhat hard and semi-watertight. Because the content of metal oxides such as iron and manganese is high enough, then the clay pottery will have fuel yellowish color, light brown, brown or red. The ideal body mass pottery has 5% porosity and shrinkage burn no more than 12%.

Stoneware clay is also found in nature or created specifically. Mature stoneware temperatures ranging from 1190

0C-13500C. The physical properties of this clay after being burned is: hard, dense, and impermeable to water (porosity) ideal can not be less than 3%. Grilled shrinkage should not exceed 14%.

Body mass porcelain body is made from a mixture of quartz, kaolin, and feldspar ballclay. Temperatures ranged mature-14600C 12500C. The physical properties of this clay after being burned are: solid, water-resistant, when a knock on her shrill, grilled white color. Power absorption of water close to 0%. For porcelain products that use bone ash, after having burned translucent properties (translucency) and is known as the type of chinaware ceramic products.

From the burning, you can find out whether the object has been burned mature, immature or too mature to perform simple physical tests, among others, by its appearance or by tapping the clay body, whether sound or not.

For ceramic factories are large, expanded into maturity test hardness test hardness tester with tools, tensile strength test, strength test o’clock, friction test, temperature shock tests and so forth. Testing the temperature of maturity for each type of clay body mass should be performed on the fuel temperature
different.

In the combustion process will occur ceramic objects changes the physical and chemical clay body mass. This process started from the loss of free water until the vitrification process or silica into glass melting process that fills the pores, resulting in a ceramic body is hard, dense and impermeable. Use three Stake Seger (PS) for three different firing temperatures, namely PS. 08 (955 º C), PS. 06 (999 º C), and PS. 04 (1060 º C) or adjust to the type of clay.