Ceramic Glaze Defects

If the glaze does not state lead free or leadless on the label assume it contains lead until proven otherwise.

Ceramic glaze defects.

Crazing consists in the appearance of network of cracks in the glaze. 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. Lead glazes should only be used on non foodware items. Applying glaze too thinly can result in rough glazes and can affect the glaze s color.

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. The surface of the glaze is very unpleasant and looks like a boiled mass of bubbles craters and pinholes. Usually crazing is due to improper glaze body thermal expansion coefficient matching. Blue ridge pottery for example is well known for glaze pops.

A large bubble sometimes present as a fault in ceramic ware. Lead glazed pottery should be labeled as lead containing. Damage damage describes defects made through use handling cleaning or storage. The thermal expansion of the glaze is too close or higher than the body.

Hold the gauge on the surface of the glaze. Design lead glazed pieces so that they won t be used for food or drink. Read on to get some expert pointers on how to solve five of the most common pottery glaze defects such as crawling shown at above. The presence of a variety of kiln marks on some types of pottery is common and is not generally considered a flaw but again should be described.

Jennifer poellot harnetty editor. Glazes that are applied too heavily or too lightly are the cause of any number of glaze defects including pitting crawling color variation and rough spots. There seem to be so many ways that bad things can happen to good pots. An adjustment of the dilatation of either the body or the glaze is required.

Glaze defects are any flaws in the surface quality of a ceramic glaze its physical structure or its interaction with the body. The most reliable way to check glaze thickness is with a thickness gauge which can be purchased through an instrument supply catalogue. Blisters appear as large bubbles either just below or penetrating the surface leaving sharp rough edges that collect dirt. In both crazing and shivering the eradication of problems relies on matching the.

Crazing is the most common glaze defect and normally the easiest to correct. Welcome to understanding pottery chapter 19. Glaze defects such as blistering are quite common when firing pottery and can be down to many things clay body glaze receipt firing method and cycle.