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