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Additional notes on Pit Firing

  • Preheat your work ( bisque or green ) around the edge of a fire until the pieces are too HOT to handle by hand.

  • Quickly stack the kiln over hot coals with at least of 4 to 6 inches of fuel, wood 2 to 3 inches in diameter. Juniper is best, then cat claw, pine is not bad -- never use oak. This wood should be very dry. If you have dung available, you can use that as it will give you a firing to around 1100o F. Dung burns hotter and longer than wood, but it was not used in prehistoric times.

  • The kiln should be covered with 2 to 4 inch diameter wood and dung to at least twelve inches thick. It will be smoking and flaming a bit at this point, the whole kiln must be stacked and fueled within 3 to 5 minutes, before it bursts into full flame.

  • NO fuel may be added after the initial stacking and ignition of the fuel, as it will take energy from the burning fire and reduce the temperature.

  • If you have straw bales available, put sheaths on as a final covering just as the kiln ignites fully, it will help keep in the heat and aid in a bit of soaking (being mostly silica, it forms a bit of a blanket over the kiln.)

  • This firing will be over in less than an hour. Mica is a good addition to the clay body as a good refractory. Saw dust as grog will aid in 'internal firing'. (Mimbres ceramics may well have had vegetable materials in it.)

  • If you are not doing a true prehistoric firing, you may use large tin can saggers with "Kingsford" charcoal in them to create a variety of atmospheres. I have had rotten luck getting a good reduction by covering up the fire with sand and dirt. Sometimes it works and sometimes it doesn't.

  • You will not get to about 1350o F with a pit firing, and with poor luck you will be lucky to hit 900o F. If you add a bit of air (long pipes and blowers) you can get to 1650o F or higher, in addition to be able to add more fuel with the use of the blower, unlike without a blower. However, if you are making your own hand dug clays, this can be quite a mess, because they will over-fire because the iron will change from a refractory to a flux in reduction.

  • Pots may be pulled out when still at 400o F and refired in an open area with Creasote Bush bundles in the interior and loose open fire of Juniper or Cat Claw on exterior for nice interior smudges, just like the Mogollon wares of the 1300's.

    Additional info on pit firing kindly submitted by Susi Nagoda Bergquist. (Supplied 'as is').

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