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.

Ceramic glaze defects crazing.

Glaze crazing or glaze crackle is a network of lines or cracks in the fired glazed surface. 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. A mismatch between the thermal. Poor application of the raw glaze to the bisqueware can lead to various glaze defects.

Applying glaze too thinly can result in rough glazes and can affect the glaze s color. Crazing is a term used to reference fine cracks that can be found in the glaze of pottery or china. Crazing and shivering or peeling of ffc. Glaze defects are any flaws in the surface quality of a ceramic glaze its physical structure or its interaction with the body.

In both crazing and shivering the eradication of problems relies on matching the thermal expansion characteristics of both body and glaze. It is caused by tensile stresses greater than the glaze is able to withstand. An adjustment of the dilatation of either the body or the glaze is required. 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.

Common reasons for such stresses are. Glaze defects can be as a result of the incompatibility of the body and the selected glaze examples including crazing and peeling. Crazing is the most common glaze defect and normally the easiest to correct. Crazing consists in the appearance of network of cracks in the glaze.

What is desired is for the glaze to shrink a little more than the body during cooling. 2 caused by glaze body fit glaze fits too tightly to clay body. It happens when a glaze is under tension. A craze pattern can develop immediately after removal from the kiln or years later.

All ceramic bodies change in size during heating firing and cooling. 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. Crazing can be present in varying degrees. Usually crazing is due to improper glaze body thermal expansion coefficient matching.

If it doesn t then glaze problems can. Immediate crazing 1 appears when piece removed from kiln or shortly thereafter. 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. We lakeside pottery know of cases where the pinging sounds of newly developed crazing lines go for many years.

The thermal expansion of the glaze is too close or higher than the body.