With the foundation complete, we set about building the base of our oven. We started by using glass bottles to create a "bowl" to hold the hearth floor. This insulative layer is meant to create an air gap under the oven, hopefully preventing the heat generated during firing from leeching into the foundation. Once we'd fashioned the floor and walls of the bowl with glass bottles, we filled the gaps with a mortar of wood shavings and clay slip.
Inside the bowl, we laid the hearth floor: a thick thermal mass of sand and clay, topped with the actual baking surface of unglazed quarry tiles (a cheaper version of the recommended "fire brick"). After the floor was laid, the next step was to build the oven dome. First, we had to make a form: using wet soil, we sculpted a smooth mound and covered it with newspaper.
On top of our form, we laid a three inch layer of oven mud: a cob-like mixture of clay and sand. This created the walls of the dome portion of our oven. After letting it dry for about 24 hours, we excitedly reached through the door-shape we'd made, and dug out the soil mound. Amazingly, the oven stayed upright and sturdy, even without the form underneath it!
Next, Tara built an igloo-like entryway out of oven mud using a cardboard form. Meanwhile, I crafted a door using our chainsaw and a scrap of wood. It was nearly dusk by the time we'd finished, but I was too excited to wait another day to use it. So, I grabbed a bunch of floodlights and got to work, starting a fire inside the oven while Tara prepared the ingredients for our first wood-fired pizzas.
The pizzas were delicious, but they took much longer to bake than we thought they would. We're not worried though, the oven isn't actually finished yet. We still need to cover the dome with a thick layer of insulation (using wood-shavings mixed with clay slip) to slow heat loss through the walls. We're hopeful that we'll be able to reach temperatures as high as 800° when this is complete. Our goal is to make a pizza in two minutes flat.