Kilns and Firing

Definition of ceramic

of or relating to the manufacture of any product made essentially from a nonmetallic mineral (as clay) by firing at a high temperature

Temperature range for firing

between 1700 and 2300 degrees Fahrenheit

What is heat work

The temperature a piece of work is subjected to for a certain amount of time (Something heated fast needs to get hotter for the heat to soak through the whole piece)

What temperature is bisque work fired to

Δ010- Δ01

Three main groups of kilns

Electric, gas, atmospheric

What are the two atmospheres inside a kiln

reduction and oxidation

Description of oxidation atmosphere

when the fuel and air are mixed perfectly allowing for a clean burn (there is oxygen remaining in the kiln), This results in an oxidized surface on pieces, colors tend to be brighter or cleaner

Description of reduction atmospheres

an environment were there is an uneven air/fuel mixture, Carbon in the atmosphere which

reacts with clay and glaze, Materials undergo Chemical Reduction, Slower firing, less efficient

three types of atmospheric kilns

Wood Fire, Salt Fire, Soda Fire

Description of Weed fired kilns

One of the oldest methods of firing, Refers to the fuel used as well as the effects resulting from the firing

Description of salt firing

form of vapor firing, Developed in the 1600’s in Germany, Salt is introduced to the kiln at high temp, The salt volatizes and forms a gas cloud of sodium, water, and hydrogen chloride, The free sodium in the glaze bonds with the silica on the clays surface, This creates sodium-silicate glass, the glaze you see on the pot, Only attaches in small spots creating the characteristic orange peel effect, Sodium is a powerful flux and will cause glazes to melt more

Description of soda firing

Originally developed as an alternative to salt firing, form of vapor glazing, Uses mixture of soda ash and baking soda, soda volatizes but not as much as salt, The kiln doesn't fill with fumes rather the fumes travel through the kiln, only some of the pots develop a soda glaze, The bare clay fluxes and will get fire color or flashing