OK: so in the course of an afternoon, I went from a firebrick hearth on a stone base
to a mound of sand, which will define the inside curve of my oven. It's wrapped in
wet newspaper. Now it's time to mix up the clay that I'll use to build the dome.
to a mound of sand, which will define the inside curve of my oven. It's wrapped in
wet newspaper. Now it's time to mix up the clay that I'll use to build the dome.
This is my secret weapon: an old pugmill I use to recycle studio clay. I know
you can mix your "cob" with a tarp, or feet, or a group of friends, but this was
my shortcut.
I spent a lot of time stressing out over what kind of mixture to use, but in the
end I threw in everything but the kitchen sink. Probably half groggy stoneware
slop, and the rest a combination of garden sand, mason's sand, and buckets
of clay soil from the footer we dug for our addition. It's mostly clay. I'll keep
you posted on whether that was a bad idea.
you can mix your "cob" with a tarp, or feet, or a group of friends, but this was
my shortcut.
I spent a lot of time stressing out over what kind of mixture to use, but in the
end I threw in everything but the kitchen sink. Probably half groggy stoneware
slop, and the rest a combination of garden sand, mason's sand, and buckets
of clay soil from the footer we dug for our addition. It's mostly clay. I'll keep
you posted on whether that was a bad idea.
I made two
wheelbarrows full of
soft, sandy clay logs.
wheelbarrows full of
soft, sandy clay logs.
It was like making a big coil pot. I angled the top of
each big coil toward the dome, so it would support
the weight of the top like an arch. I smeared each coil
into the one below it. It wasn't perfect, but I kept
reminding myself that this was just the inner dome --
the thermal layer of an oven that will eventually have
more layers added to the outside.
each big coil toward the dome, so it would support
the weight of the top like an arch. I smeared each coil
into the one below it. It wasn't perfect, but I kept
reminding myself that this was just the inner dome --
the thermal layer of an oven that will eventually have
more layers added to the outside.
It was sunny and warm and the outside "skin" of
the dome got leathery fast. I played one game of
chess with my son Connor on the deck, then cut
the door.
the dome got leathery fast. I played one game of
chess with my son Connor on the deck, then cut
the door.
I cut right through the newspaper dividing layer, and the sand
dome was still amazingly solid. I began to scoop out the sand into
a bucket. I used the door clay to make an arch for the doorway.
dome was still amazingly solid. I began to scoop out the sand into
a bucket. I used the door clay to make an arch for the doorway.
Scooping out the sand was interesting. I hollowed out the bottom center
of the dome, but there were still a few inches tight against the inner clay
walls. I scooped out what I could reach, but was worried about my
hands poking the clay through the wet newspaper -- so I just left the
layer on the back wall and roof to fall off on its own when it dries.
of the dome, but there were still a few inches tight against the inner clay
walls. I scooped out what I could reach, but was worried about my
hands poking the clay through the wet newspaper -- so I just left the
layer on the back wall and roof to fall off on its own when it dries.
I feel like I made a lot of progress for one afternoon!
Before I quit for the evening, I built a little twiggy fire in the
oven, on an iron plate. I wanted to dry it out a bit, and see
how the draft works.
Before I quit for the evening, I built a little twiggy fire in the
oven, on an iron plate. I wanted to dry it out a bit, and see
how the draft works.
I coated the inside of each log with sandless clay slip, hoping it might make
an inside coat less likely to drop sand as it heats and expands in baking.
an inside coat less likely to drop sand as it heats and expands in baking.
UPDATE!
Click here for page three!
Click here for page three!