For a few questions more

[whocanitbenow]

Hi everyone. I've been letting my hearth slab cure for about a week now and am waiting on my shipment of super isol to begin the cooking floor and dome. A few questions still persist.

1. In the plans, it seems the recommended oven opening height is between 11-12", but every photo I see just shows the opening being framed by a standing soldier brick, which I assume is 9". How does one achieve the larger height? Have a just missed something in these photos?

2. I'm using the angle iron to frame the interior opening. Does it just sit on those bricks? Does it get mortared in? And do the bricks that sit across it get notched 3/8" to account for the iron? Are those full sized bricks laying across it?

3. I was thinking about using a regular 6" metal flue pipe and base connector available at my local HVAC shop. I was then thinking about encasing that in a brick chimney. Is this ok? It will only be single lined steel (btw, my oven is 34" diameter).

4. Anyone have any good or bad experience just laying the cooking floor bricks directly on the super isol without an underlayer of sand/fireclay?

5. Should I build the vent arch and chimney first and then attach them to my dome? I heard someone mention that, but I don't remember whether it was as a good or bad idea.

6. what should i use to take the temperature of the oven once it is firing? should i install a thermocouple to digital readout system (and if so which one?) or should i get one of those handheld things that shoots infrared into the oven?

thanks so much. making this oven has been a great process, and this board is invaluable.

[Marcel]

Many ways to skin an (oven)

Hi everyone. I've been letting my hearth slab cure for about a week now and am waiting on my shipment of super isol to begin the cooking floor and dome. A few questions still persist.

1. In the plans, it seems the recommended oven opening height is between 11-12", but every photo I see just shows the opening being framed by a standing soldier brick, which I assume is 9". How does one achieve the larger height? Have a just missed something in these photos?

(M) I think that you may be looking at the very first stage illustration(s) of framing the oven. Do NOT frame it as I did in the illustration below by using bricks without mortar and having to reinforce them with plate steel at the back.

(M) Consider a variant I only thought of later; using only 4 bricks lying down ("sleeping soldiers") with a 1/2" of mortar in between each brick including the bottom brick.

(M) 4 bricks, lying down on their 2 1/2" sides and piled vertically are equivalent to 10".

(M) Four layers of 1/2" refractory mortar give you 2 more inches for a total of 12". You could reduce the mortar thickness to 3/8" or by half to 1/4" if you wanted a lower opening.



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2. I'm using the angle iron to frame the interior opening. Does it just sit on those bricks? Does it get mortared in? And do the bricks that sit across it get notched 3/8" to account for the iron? Are those full sized bricks laying across it?

(M) Again, note that builders have considerable latitude in how to construct their ovens. I did not bother notching my bricks and I know of no ovens where the builder notched them but that doesn't mean it couldn't or shouldn't be done.

(M) The next image shows both flat and angle iron across the opening. Note that I inadvertently took the picture with a brick INcorrectly oriented. That half brick needs to be turned 90 degrees so it's 4 1/2" side is resting on the angle iron:



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3. I was thinking about using a regular 6" metal flue pipe and base connector available at my local HVAC shop. I was then thinking about encasing that in a brick chimney. Is this ok? It will only be single lined steel (btw, my oven is 34" diameter).

(M) If, like most builders, the possibility of the liner coming in contact with a wooden roof is non-existent, then the single liner has some advantages in terms of heating up more quickly and providing an early positive draft. I used plenty of Perlcrete as insulation after I wrapped my flue in chicken wire. I used rubber gloves and patted the Perlcrete through the mesh. In the unlikely event of my metal liner rusting, I will still have a flue, but made of Perlcrete.




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4. Anyone have any good or bad experience just laying the cooking floor bricks directly on the super isol without an underlayer of sand/fireclay?

(M) I can't help you here as I used the original orientation of refractory mortar on top of the Perlcrete insulating layer since I wanted to hold more heat for bread baking.

5. Should I build the vent arch and chimney first and then attach them to my dome? I heard someone mention that, but I don't remember whether it was as a good or bad idea.

(M) I worked both sections at the same time to allow mutual support but there are many builders who first constructed their vent and chimney. I believe the choice is yours.

thanks so much. making this oven has been a great process, and this board is invaluable.

(M) If you want to see some 90 images of my oven building process go to:

marceld - Photobucket - Video and Image Hosting


Ciao,

Marcel

[jwnorris]

Re: For a few questions more

4. Anyone have any good or bad experience just laying the cooking floor bricks directly on the super isol without an underlayer of sand/fireclay?

I built a FB Casa110 and placed the pre-cast hearth directly on the SuperIsol without any problems. The tempature rating of the board is well above the tempature of the floor.

J W

[dmun]

Re: For a few questions more

Laying firebrick directly down on the insulating board is no problem, that's what I did. If your bricks are not of uniform thickness, you could then pick them up and place them on sand or dry mortar to level them. That's most likely not a problem.

I'm a little concerned by single wall stove pipe in an enclosed space. It can corrode, and wood smoke produces deposits that are corrosive. That stuff is designed for open air stove connections where you can see damage and replace it when needed.

[Marcel]

Single wall steel flue pipe no problem at home.

(M) P.S. My home has an indoor wood burning stove. The angle elbows are at the hottest point as they connect the stove itself. My home is over 25 years old. I have seen no corrosion in that 1/4 century and I use the stove almost daily in winter.

Ciao,

Marcel

[maver]

Re: For a few questions more

1. In the plans, it seems the recommended oven opening height is between 11-12", but every photo I see just shows the opening being framed by a standing soldier brick, which I assume is 9". How does one achieve the larger height? Have a just missed something in these photos?

An arch would work here as well - that's how mine is constructed

6. what should i use to take the temperature of the oven once it is firing? should i install a thermocouple to digital readout system (and if so which one?) or should i get one of those handheld things that shoots infrared into the oven?

Thermocouples will give you better assessment of the physics of heating your oven, but more planning is involved. I use just an infrared thermometer (designed for auto mechanic, cheaper than those marketed for cooking) which works well enough. Just remember with infrared that the thermometer gives you a surface temperature and that you need to drive heat through the thickness of the refractory material during the firing stage - with time you get a feel for this during oven use.