The nature of plastic or clay plasticity is the quality of the relationship between the clay particles were determined by the mineral content and fineness of grain of clay. Plasticity serves as a binder in the formation process so that objects do not have cracks formed / broken or deformed. The plastic properties are key requirements that must be met. Two adjacent sheet-shaped particles will stick together perfectly when lubricated with water and provide quality plastic clay and has power.
Because the structure of clay particles in the form of a sheet of hexagons overlap forming composition as bricks then difficult to have cracks, it is as shown in the figure bawah.Apabila plastic clay is not enough according to the level required by the plasticity of clay must be coupled with bahanbahan the plastic.
18.Partickle image and structure flexible clay
Clay plasticity is affected by:
1) The fineness of clay particles
2) the shape of clay particles
3) organic substances (remains of plants and animals)
4) The amount of water
5) structure (composition of particles) clay
6) the type of clay
Some types of clay are pure and natural, like the land of direct stonewaredapat earthenwarejuga digunakan.Beberapa red soil types can be directly used because it has properties as good as stoneware.Ball clay soil usually are plastic so it does not easily dried and burned without changing its shape, while kaolin is quite difficult to formed because it is too “short”, ie easily deformed not hold the load of its own weight.
The plasticity in the clay caused among others by:
1) Power cohesion clay particles are very fine and electrically charged (-) and (+) that bind to one another.
2) The water content plasticity, when viewed with a microscope apparatus through magnification 50,000 times the structure of clay particles having a flat plate-shaped flat surface. Each slab coated with a very thin water like a film. Particle coatings water function is smoothed surface plates so that each other can be mutually slipping, especially when clay is formed or under pressure and bind the particles together and form a solid mass of clay.