Wednesday, February 8, 2012

Baker's fieldguide to oven building. Part 1

The first step was to dig a proper foundation.

Concrete footings and 8 inch blocks are laid up to form the base.
There needs to be plenty of ledge room to lay stones around the block structure. 

Meanwhile work is done figuring out the span dimensions and angles for the opening.

The vault of the bake oven chamber needs to be 17 bricks across and 5 bricks deep.
Every firebrick is then cut at the proper angle.

Three inches of concrete is poured inside a wooden frame on a prepared base of plywood and rebar.

The herring bone hearth is then laid with refractory cement on the cured concrete platform .
The joints are tight and the surface perfectly level.
The stonework is starting to be laid.
The joints are recessed to give a dry laid look. 


  1. Hmm.
    EASY BAKE(ersfield) OVEN building.
    You make it look easy!

  2. The brick in your pictures are not fire-brick.

  3. It seems to me a lot of work went into this creation. To not use fire brick
    would seem a gross error considering it is an actual place for a fire! I'm sure you must be mistaken my friend !!
    Your anonymous comment upon this fell like a ton of bricks, is that why
    you don't put a name under your comment? Burning with envy perhaps?


  4. Custom firebrick. Fireplaces under scrutiny in California. Only zero clearance tolerated by code so most fireplace products not on shelves. js

  5. here is a google link to a picture of the type of brown (non yellow) fire brick we used

  6. Is there a short form for that?


  7. What you used in this oven was 'firebox' brick. Typically used in building residential fireplaces. There is a difference.
    Firebrick can take higher temperatures. Your link shows a picture of 'firebrick' correctly.

  8. Firebrick is a generic term that describes nominal refractory brick. If I recall correctly, the Refractories Institute of NA groups these into four categories: low, medium, high and super duty. What you call firebox brick is low duty firebrick and are rated for casual use at 1200-1800 F which is fine for a residential bake oven. If the oven was a commercial bagel oven or used to smelter nickel, a higher level brick is recommended. A recent discussion on the Masonry Heater Association of NA suggested that a higher level firebrick is actually less effective in a residential heater because it is designed to work at a constant higher temperature as opposed to a casual lower temperature.

  9. That's interesting professor Scott. In your first answer it was custom fire-brick, now it is low-duty fire-brick. You think you would do the research before you build the oven. It is called 'firebox brick' because the company can not legally call it fire-brick.

  10. Well Mr. anonymous, if I were you I wouldn't get near it for fear of getting burned.

  11. Mr. Kaufmann refuses to preach what he practiced in building his own oven. He used real firebrick. This is called cronyism.

  12. Most modern fire-brick is pressed. You used an extruded brick. It is now sold as firebox brick. You can see the fissures in it from the extrusion process.
      The old ASTM C27 standard that differentiated between low, medium and high duty firebrick was withdrawn in the early 1990's.  In it's place was established C 1261 Standard Specification for Firebox Brick for Residential Fireplaces which is a less stringent standard.
    According to Jim Buckley I quote, " Extruded firebrick that performs differently seems to do okay when laid as a shiner with the grain perpendicular to the firebox wall but it tends to spall when laid as a stretcher with the grain parallel to the firebox wall.
    Modern refractories are a good thing.  Build your heater fireboxes with firebrick or castible refractories."

  13. The reading up I have done (and thinking about all this) seems to indicate that you may be making a big deal about something that will not be a problem within the parameters of normal use of this bake oven. Our choice in going with the firebox brick that the client provided is within the the parameters necessary for him and us.

  14. What a strange conversation. Good luck to you, anonymous.

  15. I'm a cronyist! LOL

  16. Well Karl, at least you admit it, and evidently proud of it.

  17. What was used beneath the 3" slab for a form base? Plywood? And sp there is a cavity beneath?

  18. Would it be possible to build this without block, just using stone?