What is the purpose of the kiln?
An electric kiln is a heating chamber used to transform materials at high temperatures. A kiln hardens ceramic bodies using a process invented thousands of years ago. Clay, when heated properly, becomes hard enough to form tiles and vessels. Glazes fired over the clay become permanent decoration.
For the average electric kiln, bisque temperature will generally be reached three to eight hours after the kiln goes on high. The controller or kiln sitter shoMORE. For a fuel-fired kiln, check the cone packs every half hour.
- Most pottery is fired twice (or in some cases 3 or more time!). The first firing is called the bisque, then there is a second firing for the glaze. This is the way you probably learned, and they way you probably do it. But it is possible to fire only once.
Cone Temperature Conversion Chart Cone Temp at 108F/hr Ware and Glaze Types 04 1945 05 1888 06 1828 Bisque, Low Glaze
- Program the kiln to run a Cone 06, Medium Speed, ConeFire Program. This will take about 8 Hours to fire to temperature and another 12 hours to cool (depends on size of kiln).
Clay that is fired fast must be TOTALLY dry before it hits the steam forming temperature. When firing without a kiln, it may help to pre-dry you clay pieces in a kitchen oven set to 190 degrees F. With a kitchen oven, the pots are dried by "baking" below the boiling temperature of water for several hours.
- Polymer clay needs to be baked in a regular oven for it to become hardened and durable. You can use a regular oven, a toaster or a convection oven BUT not a microwave oven. It is fine to use a regular oven if you are not baking polymer clay too often or if you have a tall item to bake.
- Sculpey does best at about 275°F, for 10 — 25 minutes, depending on size, especially depending on thickness. Red and yellow may darken too fast at this temperature, so use a cooler oven (say 265½°F) for a little longer. Premo should bake at 275°F, for 30 minutes per quarter inch of thickness.
- For the average electric kiln, bisque temperature will generally be reached three to eight hours after the kiln goes on high. The controller or kiln sitter shoMORE. For a fuel-fired kiln, check the cone packs every half hour.
* Generally, don't open the kiln completely until the kiln temperature is below 150-250 degrees F, or thermal shock may hurt the pots and/or the kiln elements. You should be able to touch the pieces before you unload them.
Cone Temperature Conversion Chart Cone Temp at 108F/hr Ware and Glaze Types 05 1888 06 1828 Bisque, Low Glaze 07 1789 Red Family Glazes
- Pyrometric cones are slender pyramids made from about 100 carefully controlled compositions. Cones measure the amount of heat absorbed. As the cone nears its maturing range, it softens and the tip begins to bend, drawn down by the influence of gravity or the weight of the sensing rod for cones used in the Kiln-Sitter.
- You can get scientific about this, figuring out the cost of replacement elements, etc. But I figure my kiln cost about $2000 and will last 400 firings (60% low fire/bisque, 40% mid fire.) Or about $5 a load. If I were firing cone 10 a lot, I would double that.
Updated: 6th October 2019