The Malebox
2007
During the month of January (2007) some very faithful friends and I embarked on the construction of my fifth kiln, The MALEBOX. The mailbox reference is for the shape and modest size of the kiln... the male bit is for the kiln's overbuilt construction elements like the 16x16x1" solid steel door and 1.5" square stock solid steel grates. (both provided by my good buddy Mike) These features tend to make the boys grunt and the ladies roll their eyes. Thus, the MALEBOX.
The kiln has been fired several times, each time producing better results than the last. This can be attributed to the kiln's "seasoning", as the interior accumulates a glaze of ash and sodium bicarbonate. Our firings generally last about 24 hours, and we've burned about a cord and a half of wood with each firing. We burn a combination of hickory and oak, which are both extremely efficient woods with a heat values of 85-100.
The Catenary Kiln @ Union
2004
In the spring of 2004 I was invited to design and build a massive woodburning kiln in conjunction with prof. Aaron Lee Benson and the advanced ceramic students at Union University. Like all woodburning kilns, this was to be a hybrid, designed to accomodate large scale sculpture as well as functional pots.
After a winter's worth of planning and drawing with Aaron Benson we both agreed that this needed to be a walk-in kiln. Dragging monolithic sculpture through a mouse hole was not an option.
We set the interior height at 7 feet, the base width at 5 feet, and the length to nearly 16 feet. The first problem to solve was the avoidance of an underground ash pit.
The ease of a walk-in kiln would be negated by a giant hole in the doorway of the kiln. We decided to leave ground level where it was and construct a grating system out of 1" rebar, 36" off the ground. The grating would extend 36" into the kiln and span the width of the kiln, approximately 60". Our next solution was to find how to give the kiln an upward slope when we weren't breaking ground level.
I suggested casting a staggered concrete footer which would spring a unified catenary arch off of 3 seperate heights and widths. The stinker was finding the exact point, plum and level, that each section would be cast off of, as to end up with a continuous arch, 16' long.
It was a trick because as we moved through the kiln the footer had to rise and decrease in width proportionatly to echo the form of the arch. It was an architectural nightmare of a footer but we figured it out and moved forward with our plans.
Our predetermined 7'x5' dimensions turned out to be a surprisingly good guesstimate because we discovered that after the initial rise of the firebox the height and width of the kiln's interior were almost exact as we moved back in space.
Having near equal height and width is an important design element and turned out to be a gimmee on this one. After four months of thinking, drawing, crumpling, and rethinking, we called our plans good and began construction.
We began by making 13 7'x5' catenary arch forms, 1.5" thick. Using 3/4" plywood we cut 65 sections to be overlapped with staggered seams, insuring the maximum structural stability. We had estimated that the depth of the firebox needed to be about 36".
With this in mind we added 9" for the door which would be stacked within the arch and another 12" needed to taper the back wall of the fire box's ash pit.
We chose to stairstep it because it would also serve as a retaining wall for the nearly 80 cu ft of gravel, fill, and sand underneath the first firing platform. Thirty-six, 9, and 12 gave us 57" which was the length of the first section of footing at ground level.
At this point we set 9 of the 13 arch forms plum on the first level of footing, butted up against the rise of the second footing. We spanned the width of the second footing with a 2x4 and marked its height across all 9 of the arches.
Out of those 9 we took 4 and moved them up to the footing of the second rise and repeated this process...
