Two main reasons for glaze shrinkage of ceramic glaze

Two Main Reasons for Glaze Shrinkage of Ceramic Glaze

The glaze ceramic agglomerate, from curl, body glaze shrinkage phenomenon is usually referred to as the two main reasons: one is the dust in glaze and glaze of contraction. Some glaze, especially those containing tin oxide glaze, glaze: if too thick, or on the surface of a dirty, will shrink, become larger caking. A method of using a wet sponge to wipe off the dust on the surface. Set up the dust removal room to avoid dust falling. If glazing requires proper thickening in the glaze can add a small amount of bentonite (3%). Underglaze color painting is easy to produce shrinkage glaze defects, because the color of the glaze painting is similar to the remains of dust under glaze. In this case, can be mixed with a small amount of glaze in the glaze powder, or a small amount of Arabia gum.
Second the main reason is that the glaze plastic content too much, even in the dry period, the glaze shrinkage is too serious, resulting in micro cracks, the glaze cracking. In the process of firing, it is easy to form a pile of glaze, forming a block, and can not be uniformly fused to cover the body. This defect often in the burned blank. Therefore, this kind of glaze suitable in green pigment not on the beat. In order to meet in biscuiting blank, appropriate to add some such as calcined clay and clay, calcite and other non plastic raw material in the glaze. The amount of raw material added is equal to a certain amount of plastic material. In addition, the fingers gently dry friction porcelain glaze, the glaze surface becomes smooth, can also help eliminate some cracks in the glaze. In the dry glaze has not yet reached the requirements, defects and faster heating is easy to produce pile of glaze.