May 12, 2010 - 11:36am
Oven floor: Full or split fire brick
Another choice in oven construction...
For the oven floor, should I use full thickness fire brick or split? Full is 2.5" thick. Split is 1.25" thick.
My gut tells me that thicker is better, but I wanted to check with the resident TFL experts to make sure.
Thoughts? Thanks in advance...
dsoleil
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Full, you'll have more thermal mass. What you gain in thermal mass, you'll lose in space, and it will cost more. Also it will take longer to heat the stones up to temperature, I use a infrared thermometer to verify temperature before loading onto my fibrament.
The traditional way I've seen firebrick layed up for a hearth is on their sides, so they are 4" thick and 2.5" wide. More thermal mass that way since the hearth is 60% thicker.
That said, how you choose to do it will be largely dependent on how you plan to use your oven. Pizza? Thin floor & walls are fine since you cook with the fire in and don't need to rely a lot on retained heat. Bread or other baking? Thin is bad, since the oven can't hold enough heat for anything but a short bake. As with most decisions, this one is a compromise where you need to weigh the amount of construction materials, fuel & time on the one hand, with heat retention on the other.
ClimbHi
Pittsburgh, PA
Thank you so much. That's just the advice I needed, Decision made.
My oven has 4" of Foamglas, 3" cement and 2 1/2" firebrick for the floor. I boxed the dome and insulated it with insulating vermiculite. Monday evening, it took one hour and
forty five minutes to turn the dome white. I had to wait for a guest to arrive so I maintained the temperature with one or two logs at a time for an hour. Next morning the floor temperature was over 550°. Thursday at 11:00 am, the
oven floor is 240°F and the ceiling is 250°F. I have plenty of food so I'm going to load the oven with wood to dry it for the next burn.
iT'S TRUE THE THICKER THE BRICK THE MORE HEAT THE BRICK HOLDS. SO THE QUESTION IS HOW MUCH INSULATION AND MASS WILL BE PUT UNDER THE BRICK. iT WOULD BE MUCH CHEAPER TO LAY THE BRICK FLAT 2,5" & MAKE UP FOR THE RELATIVE THINNES OF THE BRICK WITH MORE THERMAL MASS AND GREATER INSULATION UNDER THE FLOOR. REFRACTORY MORTOR OR CEMENT CAN BE CHEAPER THAN BRICK, ADD DIATOMACEOUS CLAY (CHEAP CAT LITTER) WITH THE CEMENT.