The Earth Oven con't.
note: lots of details have been left out of these blog posts, but are including in the book.
NOW IT’S TIME TO START BUILDING THE OVEN
Lay out your brick floor with the tongue bricks as shown in the photos. Your tongue bricks should be a couple of inches higher than the rock base. Get the firebricks exactly where you want them because you won’t be able to move them later. We’ll add some more rocks to our base later on to bring the base to a height slightly lower than the top of your firebrick tongue. You might have to fiddle with the rocks a little bit to achieve this since the rocks are definitely not uniform, but we’re not really striving for scientific exactitude. I’ve used other brick floor configurations, but this configuration works well. Examine all the bricks carefully. You want the smoothest side up, and when you place the bricks, have them all nice and snug next to each other. Avoid gaps between the bricks and have all the bricks on the same plane with no little steps between them.
You might have to place a little sand under some of the bricks to accomplish this. Tap them gently. Your best bricks should be reserved for the center of the floor because it is here where you’ll be doing most of the baking. This is important because you’ll be scooping under your breads and pizzas with a steel peel (paddle) to take them from the oven and you don’t want to be catching on a jagged brick floor.
It is the sand dome that will define the shape of your oven, and it’s time to build it, but first fill the area between the slab and rock base with your perlite mixture. Now draw a 22 1/2 inch diameter circle on the brick oven floor, extending just slightly onto the tongue bricks.
Abbott begins to form the sand dome
Use damp sand, and pat it with your hands to get the desired shape and height. Extend the sand form right to the edge of your drawn circle. If you don’t finish it all at once, then cover the sand form with plastic to protect it from rain or from drying out.
Make the top of the dome height 14 inches. This is the height I’ve worked with, and it’s great for pizzas and breads. Very much higher or lower will change the dynamics of the baking characteristics of the oven so I’ll only stand by what has worked for us. 16 inches is also a common oven height.After the sand dome is built, you can tamp it with a board to help compress and shape the sand. Now cover the sand dome with a couple of layers of wet newspapers. The newspaper is helpful because when it’s time to scoop out the sand with your hands, you will be able to feel the newspaper and know that this is where the sand ends and the earth begins. I have to admit that once I forgot to layer the dome with newspaper, and it didn’t make any difference. I could easily feel the interior earth wall while scooping out the sand. Anyway, Abbott and Nancy used the newspaper and it provides at least, a psychological layer of security. to be con't