Contents
What does oxidation mean in pottery?
Oxidation occurs when there is an excess of oxygen. As the kiln heats up compounds in the glaze break off and oxygen attaches itself to the glaze and clay. This causes metals in both to oxidize. Reduction occurs when there is a deficit of oxygen.
What is oxidation VS reduction firing?
The terms oxidation and reduction refer to how much oxygen is in the kiln’s atmosphere while the kiln is firing. An oxidation atmosphere has plenty of oxygen for the fuel to burn. A reduction atmosphere occurs when the amount of available oxygen is reduced.
What is reduction fire?
Reduction is firing where the kiln atmosphere has insufficient oxygen for complete combustion (more fuel than air to burn it). At high temperatures, this produces carbon monoxide gas, which will steal loosely-bonded oxygen from other materials, in ceramics mainly iron and copper.
Should a bisque firing be in reduction or oxidation?
Many materials used in ceramics contain carbonaceous matter, including organic carbon and inorganic carbon from clays, whiting, dolomite, and talc. This carbon must be burned out (oxidized) during the bisque firing to ensure the best results possible in glaze firings.
How is pit firing done?
This process is done typically in a hole in the ground, or a pit, pots are placed in the pit and burned. Pit firing is an atmospheric process all of the colors and patterns are derived from the process and what is consume in the fire. Items that are burned will turn to vapor and will swirl around the pieces in the pit.
What color does copper carbonate turn if fired in a reduction firing?
The oxide form of copper can give a speckled color in glazes whereas the carbonate form will give a more uniform effect. Copper normally produces green colors in amounts to 5% where it moves toward black. In reduction firing, it turns to Cu2O and gives vibrant red hues.
How do you fire a reduction?
In reduction firing, oxygen is prevented from interacting with the glazes during glaze maturation. This is done by adjusting the fuel in a gas kiln, or by adding organic material such as in Raku. As the organic material burns it uses up oxygen, leaving an oxygen-less environment.
Can I fire pottery in a fire pit?
A pit fire is the oldest known method of firing your pottery, dating back to 29,000 BC. It works as a kiln using a hole in the ground as insulation and fuel to reach temperatures around 2000 degrees farenheit. Also, remember to use all safety precautions when dealing with fire.
What Colour is rutile?
Rutile, the most abundant of three naturally occurring forms of titanium dioxide (TiO2; see also anatase; brookite). It forms red to reddish brown, hard, brilliant metallic, slender crystals, often completely surrounded by other minerals.
What’s the difference between reduction firing and oxidation firing?
Reduction Firing Most usually, reduction firing is favored by potters and is done using gas, propane or other fuel burning kilns or methods. Reduction firing is the exact opposite of Oxidation firing. It is the lack of oxygen in the last part of the process that is critical for the desired effects.
What does oxidation and reduction mean in a kiln?
There are many factors to consider when it comes to firing your pottery in a kiln. The terms oxidation and reduction refer to how much oxygen is in the kiln’s atmosphere while the kiln is firing. An oxidation atmosphere has plenty of oxygen for the fuel to burn.
When do you use oxidation and reduction atmospheres?
There are many factors to consider when it comes to firing your pottery in a kiln. The terms oxidation and reduction refer to how much oxygen is in the kiln’s atmosphere while the kiln is firing. An oxidation atmosphere has plenty of oxygen for the fuel to burn. A reduction atmosphere occurs when the amount of available oxygen is reduced.
How does the oxidation and reduction process affect pottery?
The oxidation process, for example, can alter the color of the glazes or paint you’ve chosen to use. The reduction process, when oxygen is leeched out of your kiln atmosphere and pottery, can change the texture of your clay.