Superior Clay 18" Bake Oven
(Tecleo aqui para las instrucciones en espanol)

  • 40 firebrick for hearth floor and sides
  • 20" dome
  • 10" entrance tunnel
  • HeatStop II - 10# pail
  • Insulating castible - three 50# Bags
  • Entrance cover

    These components may be priced and sold separately. Additional materials such as brick, stone, block and additional clay flue liners may be needed for base, surround and chimney.

Masonry Bake Ovens
Letezeio 18" Oven Under Construction

Building the 18" Superior Clay Oven

1) Build masonry base at least 34" wide by 46" deep, and 38" high for a finished oven floor 42" above the kitchen floor or ground.

    The inside of the oven is 18" in diameter (actually a pentagon) and the walls will be about 8" thick so the base should be about 34" wide and 46" front-to back-to allow for a 12" counter or hearth extension in front of the oven entrance.

2) Cast a 2" thick layer of insulating refractory concrete on top of the base and set the firebrick oven floor directly on the insulating refractory concrete.
3) Lay out 18" circle on oven floor and set 10 firebrick in Heatstop II refractory mortar just inside circle as shown, five sides each with one brick layed flat and one brick layed on edge on top of the first brick, so that firebrick walls are about 7" tall.

4) Set the 20" oven dome, the 10" entrance tunnel (with flue opening toward the dome) and the first flue tile all in Heatstop II refractory mortar.

5) Parge the sides and top of the oven with the insulating refractory concrete at least 2" thick.

6) Add more insulation over the castable insulation. Inexpensive pearlite or expanded shale mixed with a little Portland cement is okay - or use mineral wool. Whether the oven is associated with a cooking fireplace and large chimney mass or is a stand-alone oven, the exterior masonry enclosure should be isolated from the oven shell by an air space or a layer of compressible insulation like mineral wool so that, when the oven liner expands with heat, it doesn't crack the exterior masonry. Some masons use metal lath held away from the oven shell with spacers to create an air space and then plaster the oven dome. Many ovens are covered by a roof to keep rain water from entering any cracks in the exterior.

7) The 4"x 8" flue liner should be enclosed within a chimney with walls at least 4" thick of solid masonry. If the chimney is inside a house it must conform to all applicable codes dealing with clearance to combustibles and height above the roof. If the oven is outside the flue need only be enclosed in masonry as high as is desired and clear of combustibles.

8) An entrance cover for the oven entrance can be provided to help keep the oven warm. When a fire is heating the oven the door can be placed toward the front of the entrance so that flue gasses can enter the flue. After the oven is warm and the fire is out the door can be placed farther in the entrance to close off the flue, seal the oven better and preserve the heat.

Cooking in a Black Oven
(thermometer recommended)

The Superior Clay Oven is a "black oven" meaning that it is heated by building a fire in the oven itself.

Some foods, such as pizzas, cook fast in a hot oven - three minutes at about 700 degrees F - and are cooked in the oven while the fire is still burning. When ready to cook throw some corn meal on the oven floor and bake right on the hot firebrick. The oven door can be placed near the outside of the entrance to keep the oven hot and not so far in as to block the flue while the fire is still burning.

French bread is traditionally baked in a periodic oven with a moist atmosphere and declining temperature. Get the oven up to about 400 degrees F. Rake out the fire and mop the hearth with a wet towel. Load the oven with enough bread to fill the oven to keep the moisture high. Push the oven door all the way in past the flue entrance to seal in the moist heat until the bread is baked.

Meats and roasts can also be seared and roasted in a periodic oven with declining temperature after the fire has been raked out.

The oven can be used as a smoker by keeping the temperature low, using the right wood and maybe a pan of liquid, depending on the recipe. And, of course, the oven is a great place to warm plates as it continues to cool.

Building Fires

At first, at least 24 hours after building the oven, build a small fire to break in the oven. Try to build up the temperature inside the oven at a rate of 50 degrees F per hour up to about 500 degrees F. The break-in fire will drive out any moisture, cure the refractory mortar and minimize the chance of damaging the oven.

Many oven domes crack even when broken in properly. The purpose of the dome is to create the dome shape in the oven that cannot easily be achieved with other materials that would not crumble or scale off into the food or cost many times more. The cracks have no negative effect on the oven and a cracked dome will last a lifetime, be structurally sound and perfectly functional.

Graphic courtesy Alan Scott

To build a fire start with a small kindling fire in the front of the oven under the flue. Add wood when the fire is burning well, and gradually move the fire back into the oven. Use the oven door (when you are not adding wood) placed out near the front of the entrance tunnel to keep heat in the oven but not block the flue while the fire is burning.


Building Fires and Cooking in Your Superior Clay Bake Oven

Superior Clay Bake Ovens
Buckley Rumford Fireplaces
Copyright 1996 - 2010 Jim Buckley
All rights reserved.