24" Oven

Buckley Rumford Fireplaces
Superior Clay 24" Bake Oven
1/21/20
(Tecleo aqui para las instrucciones en espanol)

Plan
Secondary Air
Superior Clay Bake Ovens

Components:

40 firebrick for hearth
Two Base Sections
18" Two Piece Entrance
18" Dome
4"x8" or 8"x8" clay flue
HeatStop II - two 10# pails
4"x8" Clay Flue
Insulating Castable - four 50# Bags
18" 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.
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INSTRUCTIONS

Building the 24" Superior Clay Oven
1) Build masonry base at least 40" wide by 52" deep, and 38" high for a finished oven floor 42" above the kitchen floor or ground.
The inside of the oven is 24" in diameter and the walls will be about 8" thick so the base should be about 40" wide and 52" 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 a 24" circle on oven floor and set the two piece entrance tunnel and two oven base sections as shown using HeatStop II refractory mortar.
4) Set the oven dome and the first flue tile all in Heatstop II refractory mortar.
5) Fill the voids in the base sections and parge oven dome with insulating castable refractory 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"x8" 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 is provided. Set just in the front of the entrance, the cover allows enough air in for combustion. The cover can be pushed in farther against the seat in the tunnel to close off the flue to keep the oven warm longer after the fire has burned out.
9) Secondary air is not necessary but can be added to speed up combustion and reduce emissions in the early part of the fire.

10) Finish
The oven can be finished in many ways. See the pictures.
Since the liner base sections are hollow and filled with insulation, they can be glazed or painted (or not) with no need for any enclosing masonry.
Here is one example using a terracotta entrance, spacer and larger raincap dome.
Marty Myer builds a 24" oven
Building Fires and Cooking

Building the 24" Superior Clay Oven 1) Build masonry base at least 40" wide by 52" deep, and 38" high for a finished oven floor 42" above the kitchen floor or ground. The inside of the oven is 24" in diameter and the walls will be about 8" thick so the base should be about 40" wide and 52" 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 a 24" circle on oven floor and set the two piece entrance tunnel and two oven base sections as shown using HeatStop II refractory mortar. 4) Set the oven dome and the first flue tile all in Heatstop II refractory mortar. 5) Fill the voids in the base sections and parge oven dome with insulating castable refractory 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"x8" 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 is provided. Set just in the front of the entrance, the cover allows enough air in for combustion. The cover can be pushed in farther against the seat in the tunnel to close off the flue to keep the oven warm longer after the fire has burned out. 9) Secondary air is not necessary but can be added to speed up combustion and reduce emissions in the early part of the fire.