WOODFIRING
SOUTH JERSEY KILN
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construction phase to the closing up for the first firing. Below are some
more pictures of the kiln from construction and results from various
woodfirings. This kiln was designed in 2000 and has had much use since
then. Even so, the kiln is holding up very well.
Linda Shusterman
Willoughby, the Excutive Director of The Perkins Center for the Arts in collaboration with the Appel
Farms Arts Center in southern New Jersey.
This woodfired kiln is used mainly by artists from the community in Pennsylvania, New Jersey and by
art centers in the area. The requirements for this wood kiln design were varied and complex. As usual,
the kiln had to have the ability to fire fast (14-18 hours) for woodfiring workshop situations. It also had
to be able to be fired for a long period of time. Since wood size and availability is always an issue, the
kiln had to be able to fire with small or large wood sizes as to minimize the use of chain saws by
inexperienced participants. The first chamber was not going to be salted but the second chamber
needed to have the option of using salt or soda during the firing. In addition, the fire box area had to
accommodate space for pots to be stacked to yield anagama like effects. Lastly, the kiln also had to
have the ability to stop or reduce the typical black smoke that arises from the chimney stack. The
chimney itself had to be shorter than most and yet had to draw well in any weather conditions.
We decided to put a small anagama type structure on the front as the main fire box using a step grate
with many air intake ports. This helps fine tune the atmosphere and rate of combustion. The steps as
grates also lets the flame and expended gases completely fill the fire box which would help yield the
anagama effects desired.
The first chamber has duel stoking pots on each side of the chamber so wood can be stoked at the
base of the chamber. This allows a variety of stoking patterns between the main box and the chamber
firebox as well, creating a good coal bed on the base of the chamber for more radiant heat and flame,
which helps the kiln fire fast if needed. The ash pit of the chamber fire box is 13 1/2" wide so there is
no need to rake out coals (thus heat potential) from this area when firing. Ash pit access areas are on
both sides of all chambers to allow cleanup after the firing to be an easy task. The bagwall design
differs from the "laws" of construction theory in that the spacing is tighter than normal, especially near
the bottom and looser as the bagwall gets higher. The height of the bagwall is also higher than most as
the flame has to be coaxed up and over the arch as well as through the chamber.
The second chamber is identical to the first in its construction and features although it does step up
from the first chamber. The second chamber exit flues are spaced wider apart and higher than most
kilns, another violation of construction norms. The exit flues of the chamber lead into the collection box
area at the base of the chimney stack. The chimney itself is made of hard brick until about two thirds of
the way up when we switched to using soft brick for about 10-12 courses. Then hard brick is used for
the remaining chimney. We did this after talking to Mr. Greg Pitts (NY) about draw considerations. The
pressure is higher inside the stack at the lower part of the chimney since hard brick absorb and
radiate heat. The soft brick do not absorb as much heat as do the hard brick. This causes a pressure
differential, which in turn makes the chimney pull more efficiently under any conditions. This little trick is
useful when building small chimney structures, or any chimney a far as we are concerned.
This kiln has been banded with iron around all the kiln structure. The fire box and chambers using 3"
angle iron and channel iron. The floor also has 9" brick and 13 1/2" brick spaced every other one as to
lessen the movement of the floor and bagwall during expansion when firing to high temperatures (cone
10 or above).
The kiln has been fired many times (50+ firings i believe at this point) and has produced great results
in both short and long firing cycles.