Sunday, 14 February 2010

Kiln Building in 1990 -A pictorial essay.

After I stopped renting premises for my pottery, I had a big heap of materials, and the equipment I'd not managed to sell, racks and so forth, and a couple of big stacks of second hand firebricks on what had once been a garden at home.
I had a bit of space inside, enough to make a few pots, and just across the yard was a factory unit which made furniture frames out of kiln dried hardwood. It costs a business like that a lot of money shipping the offcuts away, so it was only natural that my brother and I put all the old fireplaces in the house back into use, installing a woodfired cast-iron stove with a water heating coil, too.
And of course, it was only natural that a pyromaniac potter would decide to knock down the raku kiln and build a nice little woodfire kiln. 
The kiln was a mashup, a hybrid. Well, up to the arch it was a strightforward Fred Olsen Fastfire,  I'd been in correspondence with Nils Lou some time previously, and he'd sent me his plans for what looks like a terrific kiln, the Minnesota Flat-Top, which I'd always planned to be my studio kiln, the place I eventually ended up renting refused to let me have a flame-fired kiln, due to their insurer's fears, and ignorance of the nature of kilns. So I had been all-electric there.
The MFT's roof was a compression structure, which allowed it to remain flat, with no fear of collapse. I liked that. I've built arches the hard way, cutting and shaping. With this, it's just standard bricks, on end, lightly buttered with clay slip, and clamped up by steel bars acting on the corners. I think I put hard firebricks in the corners to take the crush-load a bit better.
Here's a blow-by blow photosaga.
Concrete slab, 6", with reinforcing mesh, followed by a layer of flat-laid hard firebrick.

Firebox walls are hard firebrick. Two opposing equal fireboxes.

Floorslabs, from Butterley Brick, I paid for these, but they were very generous in letting me pick over their refractory seconds and scrap pile.

Walls were large K-23 insulating firebrick, bought very cheaply after they'd been used for the international potters-camp kils at Aberystwith. Lots of people wanted them, but few had the ability to truck them away. I had a big van and trailer.

Almost there!

Dill-the-Dog getting underfoot and stealing bits of wood to chomp on.
The chimney seen here was for use in drying-out, this was 8", it really needed a 10", rising to 12ft above the kiln floor. Door was bricked out of normal size K-23s, bagwalls were hard firebrick. Grates were welded out of 1" rebar, and angle sections, all sourced from construction site salvage.
Firing in 6 hours to 1300degrees C (2370degrees F)(stoneware), was quite easy, though I preferred closer to twelve hours, with a small fire lit the night before in the front firebox to ensure a dry start to the main firing.
Not too long after it was built, my source of dry hardwood went bust! Damn! No big problem, though, it could be fired on oil or gas with only a little alteration.
However. I was persuaded to start making stuff for a couple or three other potters, in their workshops, which I did for a while, making things that they could envisage but  lacked the ability to throw, so it was a mix of production and tutoring,  I still wanted to do my own thing though,  so I stopped all that, and started working in building and plumbing in order to try get the  taxman off my back. I was so disillusioned by my experiences with shops and galleries defaulting on payment to me, and me going into bankruptcy with a tax man threatening me on a regular basis, that I abandoned potting altogether until last year.

On the Difficulties of Visiting One's Valentine.