Glaze over is mainly used on pottery to waterproof it and on stoneware and porcelain pottery for adornment. Glaze is also used on materials used for construction such as stones and tiles. Glaze may be applied as a dry mixture dusted on the top of a clay surfaces object, and also by putting salt or soft drinks in high-temperature kilns to make sodium vapor, which interacts with the silica and aluminum oxide in the amaco clay to deposit a glass finish on the object. On the other hand, the most frequent type of glazes are liquid glazes which are suspensions of metallic oxides and powdered vitamins. They are applied by pouring the glaze over the item, by dipping the objects into the glaze over, by spraying the thing with an airbrush, or by painting the glaze over on the object. Frequently all or part of the bottom associated with a target is left unglazed, or located on stilts or kiln spurs, in order that the thing doesn’t stick to the kiln.

Mayco Stroke and Coat Glazes ( You can see the full range, here: https://ceramicartsandcrafts.com/category/mayco-stroke-and-coat.html ) may range from complete opacity to complete transparency. Opaque glazes are caused by very small air bubbles or contaminants in the glaze suspension system; many glazes which look white are actually opaque rather than containing a white pigment. Decorations applied to the clay beneath the glaze is classified as underglaze, which is often applied either to raw, unfired or to bisque-fired (already fired) pottery. Transparent wet glaze over is applied over the underglaze, and the colors in the underglaze blend with the glaze.

The well-known blue and white clay pottery art of Holland, England, Japan and China is an example of the underglaze technique. The characteristic blue color comes from the cobalt oxide or carbonate in the glaze formulation. When adornments are applied over a layer of glaze, they are termed overglaze. Overglazes are fired at low temperatures and provide a glassy appearance. The color of a glaze is afflicted not only by its substance composition but also by the atmosphere in the firing kiln.

A kiln with a high level of oxygen produces an oxidation firing while a kiln low in fresh air produces a reduction shooting. An oxidation firing of copper carbonate glaze produces a turquoise color, but a reduction firing of the same glaze produces a bright red.
Getting the correct glaze is a science itself. Elements which need to be taken into account are the firing range, the ingredients, and the use to which the item will be put (for example, tableware objects require non-toxic glazes). The firing range is determined by the sort of clay surfaces that are used. Mid-range stoneware clay require mid-range glazes and low range earthenware clays require low fire glazes.

Although many professional ceramicists formulate their own glazes to achieve specific effects, beginners are advised to use commercial formulations whose properties are well-known and tested. Industrial suppliers provide sample porcelain tiles which indicate properties such as surface texture, color, transparency, and food-safety.

The knowledge of glazes in clay pottery art is a science unto itself. In addition to commercial formulations which are taken into account, selecting the correct glaze over requires consideration of what artistic effect is desired; also to what use (e. g. dinnerware) the subject will be placed.