Most of the the work on our wood-fired pizza oven has been about the supporting structure—the foundation, the stand, and the insulating platform. Necessary stuff, but it doesn't have much to do with cooking a pizza. Last winter was a long one and when I was ready to start building the dome this spring, there was more delay as rain fell for a month solid.
It gave me time to consider the firebricks stacked on a pallet in the yard. A firebrick is larger and heavier than a regular clay brick and perfectly at home in temperatures that can reach 700 degrees. What makes them so unique at holding the heat is a heavy dose of aluminum oxide and silica.
There were no mishaps in transporting 200 firebricks home—just two trips to protect the suspension in our beleaguered vehicle. Along for the ride were three-50 pound sacks of heat-proof cement and a sack of fire clay (basically firebrick dust). Don't forget a shiny new diamond-tipped saw blade for cutting the bricks on a power-saw. (Yes, some use a special water-cooled brick saw, but I was going to try to use the tools I already had on hand.)
I set the oven floor first. I mixed one part fire clay dust with one part sand and enough water to make a thick slurry. Down went a two inch layer of the stuff on top of the insulated top of the stand, and before it dried, I fit together twenty bricks in a herringbone pattern tapping them in tight with a rubber mallet. This was where the actual pizzas would go! I'd be sliding those pizzas in any day now. (Right!)
Not so fast: There was a dome to build. The first course is half-bricks set on end, gently curving to conform to the diameter of the oven. I had cut a 40-inch round template from plywood and used the diamond blade to cut a half-dozen bricks through the middle. (I wore a respirator and safety glasses, and cutting the bricks wet helped keep the dust and flying particles down.)
With the first circular course in place, buttered together with a smooth heat-proof mortar, I began to shape the dome. I replaced my plywood template with a slightly narrower diameter to help support the first course of dome bricks and spread a thick wedge of mortar on half a brick. I set it with the finished edge tipped into the interior of the oven. So sitting on the four-inch tall vertical half-brick was a horizontally oriented half firebrick. It held. I set another one next to it, gradually moving around the circle to form the dome. So far so good.
Years ago in Florence, Italy, I stood with three college friends on a hill with a view of the Cathedral—the Duomo. Four million bricks and sixteen years of construction just to build the dome. Well, the whole idea made us all hungry—we were always hungry, and in Florence there was always pizza. Along the winding back streets of Firenze we discovered cheap wood-fired pizza made with buffalo mozzarella and fresh tomatoes. Somehow the Duomo and pizza became forever linked in my mind.
By the time I reached the third tier of my own Duomo I realized I was no Renaissance craftsman. Bricks slid apart as the angle of the dome increased. I cut scraps of wood to use as props for each brick to hold them in position. But I could only place a few bricks down at a time to keep the weight from shifting them. I worked my way around to a keystone that I had cut to an exact fit using a cardboard template. The keystone "locked" the bricks in place on the row.
As I made my way around the dome, I left an opening for the archway into the oven. I had stacked four bricks on each side as a placeholder. The arch would have to be finished before the dome. Now if I thought tipping bricks up was hard, the arch would teach me just how hard it was to go fully-vertical with a brick!
Next: The Roman arch takes shape.