Ceramic Glaze Defects Crazing

Commonly called guan kuan crackle the ru guan and ge ware were all beautiful examples of crazing as a decorative technique.

Ceramic glaze defects crazing. If it doesn t then glaze problems can. Glaze crazing or glaze crackle is a network of lines or cracks in the fired glazed surface. The thermal expansion of the glaze is too close or higher than the body. Poor application of the raw glaze to the bisqueware can lead to various glaze defects.

All ceramic bodies change in size during heating firing and cooling. A craze pattern can develop immediately after removal from the kiln or years later. Crazing is the most common glaze defect and normally the easiest to correct. Common reasons for such stresses are.

It is caused by tensile stresses greater than the glaze is able to withstand. What is desired is for the glaze to shrink a little more than the body during cooling. Crazing is a term used to reference fine cracks that can be found in the glaze of pottery or china. Crazing crazing a network of spidery cracks in the surface of the glaze.

May be described in estimated percentages or by location as in light crazing over 100 of the item or heavy crazing on the pedestal only light crazing very light and only visible upon close inspection. Glaze defects can be as a result of the incompatibility of the body and the selected glaze examples including crazing and peeling. Applying glaze too thickly can cause the glaze to run off the pot weld lids to pots and pots to kiln shelves and can result in blistering. Applying glaze too thinly can result in rough glazes and can affect the glaze s color.

Sometimes items may have a couple of crazing lines on one side and not the other other times the crazing can look like a spider web and cover the entire item. In both crazing and shivering the eradication of problems relies on matching the thermal expansion characteristics of both body and glaze. Glaze defects are any flaws in the surface quality of a ceramic glaze its physical structure or its interaction with the body. Crazing is a spider web pattern of cracks penetrating the glaze.

Crazing and shivering or peeling of ffc. Crazing is often thought of as a glaze defect but as nigel wood describes in his book chinese glazes the song dynasty potters are thought to be the first to treat crazing as a decorative effect. 2 caused by glaze body fit glaze fits too tightly to clay body. We lakeside pottery know of cases where the pinging sounds of newly developed crazing lines go for many years.

Crazing consists in the appearance of network of cracks in the glaze. A mismatch between the thermal. It happens when a glaze is under tension. An adjustment of the dilatation of either the body or the glaze is required.

Usually crazing is due to improper glaze body thermal expansion coefficient matching.