Ceramic Glaze Defects Crazing

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

Ceramic glaze defects crazing.

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. Crazing consists in the appearance of network of cracks in the glaze. We lakeside pottery know of cases where the pinging sounds of newly developed crazing lines go for many years. Crazing crazing a network of spidery cracks in the surface of the glaze.

All ceramic bodies change in size during heating firing and cooling. Immediate crazing 1 appears when piece removed from kiln or shortly thereafter. Applying glaze too thinly can result in rough glazes and can affect the glaze s color. 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. A mismatch between the thermal. Glaze defects can be as a result of the incompatibility of the body and the selected glaze examples including crazing and peeling. 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.

2 caused by glaze body fit glaze fits too tightly to clay body. It is caused by tensile stresses greater than the glaze is able to withstand. Common reasons for such stresses are. 1 body glaze interaction problems 1 1 crazing 1 2 peeling 2 metal release 3 glaze surface defects 3 1 blisters 3 2 crawling 3 3 metal marking 3 4 pin hole 4 references 5 external links glaze defects can be as a result of the incompatibility of the body and the.

Glaze defects are any flaws in the surface quality of a ceramic glaze its physical structure or its interaction with the body. 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. An adjustment of the dilatation of either the body or the glaze is required.

In both crazing and shivering the eradication of problems relies on matching the thermal expansion characteristics of both body and glaze. Commonly called guan kuan crackle the ru guan and ge ware were all beautiful examples of crazing as a decorative technique. If it doesn t then glaze problems can. 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.

It happens when a glaze is under tension. A craze pattern can develop immediately after removal from the kiln or years later. Crazing can be present in varying degrees. Glaze crazing or glaze crackle is a network of lines or cracks in the fired glazed surface.

Poor application of the raw glaze to the bisqueware can lead to various glaze defects.