Without doing a thorough testing of clay, yet it is known that clay including what type of clay, how plasticity, how the temperature grilled, and whether the clay can be used without mixing it with other clay materials. Clay testing process can be done with one type of clay (single clay) or with a mixture (formula) clay bodies that meet the requirements for making ceramic objects. This clay testing process needs to be done so that the physical properties of clay known chemistry.
In terms of physical test, which is done most fundamental measure of dry shrinkage, shrinkage fuel (shrinkage amount) and porosity (water absorption in clay that has been burned). Being in terms of chemical test, to be seen whether in the clay containing other inorganic materials such as calcium oxide, gypsum, alkali salts and so on, which is considered a pollutant and a major cause of damage in the manufacture of the final product.
The thing to note is that in the process of testing clay, the type, nature and function of clay materials must be understood first, it is necessary to avoid the risks or failure to timbuil in the testing process. Primary clay (residue) and coarse particles have different sizes.
Instead clay particles secondary (sedimentary) is more subtle, uniform and lying parallel to each other. Because the finer the particles, it will absorb more water so that secondary clay becomes more plastic than with primary clay. The materials include secondary clay, such as bentonite are highly plastic, will not be used by itself. Materials such as ballclay, is a compound for the manufacture of the plastic mass of clay.
Clay which is basically less plastic, usually 20% plus 5% bentonite ballclay or to mass produce ready-made clay. Several types of ready-made clay containing 40% ballclay, but because of the nature of ballclay which absorbs a lot of water, shrinkage becomes relatively high.
In the process of testing the clay needed to facilitate the successive stages in the implementation, ie
1. Election mixture (formula) clay body
2. Preparation of clay body
3. Testing the plasticity of the clay body
4. Testing dry clay body shrinkage
5. Testing temperature clay body maturation
6. Testing Fuel clay body shrinkage
7. Testing porosity clay body
8. Analysis of the results of the testing clay body