Ceramic Reduction Fire Definition

Reduction firing is typically done in a gas or other fuel burning kiln since the corrosive effects wear out the elements on an electric kiln.

Ceramic reduction fire definition.

In traditional ceramics reduction firing requires a specially designed fuel fired kiln that restricts the flow of incoming air so there is enough to burn the fuel and no more in some cases it is restricted so that is actually less than enough to introduce carbon into the atmosphere. Ceramic work is typically fired twice. The piece is inserted into the garbage can and the lid put on. A reduction atmosphere occurs when the amount of available oxygen is reduced.

An oxidation atmosphere has plenty of oxygen for the fuel to burn. Moving quickly the hot pieces are put into a reduction environment. Firing converts ceramic work from weak clay into a strong durable crystalline glasslike form. The oxidation process for example can alter the color of the glazes or paint you ve chosen to use.

A reduction environment is an enclosed space with a reduced amount of oxygen. Most pottery professionals don t like to describe it especially to a persnickety chemist. It is the lack of oxygen in the last part of the process that is critical for the desired effects. This may not sound like things that will affect your pottery but it can.

Usually this consists of a metal garbage can with combustible materials inside such as newspapers saw dust leaves or pine needles. If you want more time in reduction without more heat work reduce the amount of fuel you may also need to reduce air intake and close the exit flue or damper even more so that the kiln is soaking rather than gaining heat. Reduction causes most ceramic materials such as your glazes to melt faster. Reduction firing is the exact opposite of oxidation firing.

The goal of bisque firing is to convert greenware to a durable semi vitrified porous stage where it can be safely handled during the glazing and decorating process. This is done by adjusting the fuel in a gas kiln or by adding organic material such as in raku. It is bisque fired and then glaze fired.