Over the last couple months, things have changed. A smaller kiln is in the works. Smaller everything...amounts of wood, firing time, firing crew, prep time in general. Quick turnaround....versatility will be a bonus! Fortunately, my friend and fellow potter, Stephen Rodriguez, has accrued a hefty stock of both soft and hard bricks over his thirty years or so of gas kiln building experience. Between his bricks and fellow potter, Louise Harter's 1000+ Empires, a small kiln may be ready to fire in the next 4-6 weeks. We've nearly completed the base layer of the kiln.
To begin with, the pad was excavated to level, layered with 3/4" gravel and a cinder block base was laid dry....two high/18'. Then we layered the top of the cinder block base with 1/2" cement board. Building a 2x4" frame, we cast the slab using a mixture of cement, 1/2" gravel, plenty of perlite and sand. A pure concrete slab 3:2:1 Gravel/Sand/Cement was cast for the chimney base slab. The firebox floor was cast in a heavier perlite ratio than the chamber slab.
We then cut and fit high alumina 5/4" shelves for the floor of the firebox and layered the chamber floor with 12x18" soft brick lintels. For the firebox arch, Stephen free-styled a sprung arch curve, I traced and created a form using plywood and a jigsaw. We cast the firebox grates with Mizzou castale and are now in the process of, having placed hard brick lintels around the permanent shelf posts, cutting and fitting hard bricks around the newly places hard brick 12x18" lintels.
The form for the kiln chamber is a graduated 1:1 catenary arch. The interior opens up to the center section and tapers to the tail...a 1:1 ratio is maintained throughout the chamber. It was made from plywood cut to a gravity-formed archs and bound by 1/4"x10' strips of Ash.
The chimney will be 36x36" on the exterior to 6' height and corbel to a 14" square opening to 13'.
The firebox is roughly 1/3 or the chamber floor area. Stacking depth is 6.5' with an average height/width of 42". Stackig space will be approximately 60c.f..
There's a lot of work left yet but we've taken care to make a solid base for the kiln. The firebox has 3-3x36' grate slits and they are divided by the 9" depth of the castable grate.
Hoping to fire in the next couple months..this summer for sure ;)
A 1:1 catenary arch has the equivalent of exactly 2/3 the area of a 1:1 square of the same dimension.
42" average height and width equals 1764square inches/inch.
1 cubic foot =1728
21,168/1728=12.25 cubic feet of stacking per foot.
6.5' chamber length x 12.25 cubic feet stacking per foot of chamber=79.625
At least 75 cubic feet of stacking will be available.