Each fuel-fired kiln will fire a bit differently, so expect to work with yours over a period of time before you find what works best with it. Even so, the basics are the same.
Natural gasPropaneWoodOil
Don’t be confused by other reduction techniques that many potters use. Out-of-kiln reduction techniques such as western-style raku, pit firing, and barrel firing are different from in-kiln reduction firing. This article is only talking about in-kiln reduction. Reduction cycles are generally done from a half-hour to an hour and a half during the very last stages of the firing, before shutting the kiln down to cool. Do check your cone packs at least every fifteen minutes. Reduction causes most ceramic materials (such as your glazes) to melt faster. 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. The kiln does not have to be air-tight, but it should be shut off from most air-flow. (If the damper/flue is completely closed and all peepholes into the stack area are plugged, the pressure in the kiln will keep air from entering the portholes, as long as the kiln is large enough and the burner ports are not too large. Leave the kiln closed until it is cool enough to unload.
