There are 3 basic components to every pottery glaze. They are the refractory component, the flux component and the glass making component. Each component has a specific role in making the glaze function to cover and seal a pottery piece. They work together to form a glass barrier between the clay and the outside world. These are the basic components necessary, but others are added to enhance glossiness, color and thickness of the glaze.
The glass making component is the most notable of the 3 because it changes the glaze into a glassy substance that will fill the surface of the piece and form a protective barrier. The most common glass making component is silica sand. This material is cost competitive and readily available on a commercial basis. It is a form of silica that does not contain a gross amount of impurities, and it makes mixing the recipe for a glaze easier without the issues of compensating for impurity factors.
The flux component of a glaze works as a glue. It assists the other elements of the glaze to adhere to the piece instead of melting onto the shelf of the kiln. It holds the glaze where it needs to be, and at the correct thickness, during the heating process. Without flux, the glaze would have to be added in layers and the piece would need to be fired between each layer. This is inefficient and could damage the piece before it is completely finished.
The refractory component of a glaze assists with the heating process. Silica sand has a relatively high melting temperature. In order to be able to heat a piece high enough for the glaze to set without a refractory, the piece might explode due to excess heat before the glassy layer forms. The refractory material reduces the temperature at which the silica will melt. This means the glaze will coat and penetrate the outer surface without overheating the piece.
Each of these basic components is present in every glaze recipe. Other ingredients are added to the mix for enhancing facets of the pottery such as color, opacity or matte finishes. Each recipe has its own mix and is meant for a different type of pottery, a different kiln temperature and finished look. Many recipes are registered and commercially available.
In terms of decoration or branding, apply inglaze decals to your finished work.