oven floor temperature - need some data

[strobes]

Hi,
I need some help from builders that have temp sensors installed between floor and insulation board. please share:
1. how long takes to saturate floor made from low duty firebrick 2.5" thick.
2. what was max temperature you have measured in that area?
I know every oven different but still I can use this data.
Thanks!

[Les]

Re: oven floor temperature - need some data

Hi,
I need some help from builders that have temp sensors installed between floor and insulation board. please share:
1. how long takes to saturate floor made from low duty firebrick 2.5" thick.
2. what was max temperature you have measured in that area?
I know every oven different but still I can use this data.
Thanks!

Strobes - not sure what you are looking for here. I did not install sensors but I can pretty much guarantee that a saturated brick is the same temp on all sides. The time is a huge variable - I use a moderate fire and it takes about 2 1/2 - 3 hours to get my 42 inch oven to temp. By that I mean that it has burned clean which is an indication that the brick is saturated.

[strobes]

Re: oven floor temperature - need some data

Les, can you please explain " it has burned clean"?
I'm thinking that it turns "white" about 500F. But from that point brick's temperature can go till it equals to coals temperature if fire going for long enough? Will it ever reach 900-1000F?

[Greenman]

Re: oven floor temperature - need some data

Hi Strobes - The dome does 'clear', the carbon burns off when it gets up to temperature. I have never recorded the temps that it happens but I suspect that it is about 5-600 degrees f. It is a good indicator that the oven is up to pizza temps or near to it.

i have measured the temps of various parts of the brickwork inside the oven to over 950 f and some parts have exceeded the limit of the infra-red thermometer.

It is possible to get significant heat onto the surfaces in the oven with big fires but the longer slower fires saturate the oven. I seldom use the thermometer these days and rely on the time that the oven has been fired, the intensity of the fire and the 'feel' of the thing.

It has a fair bit to do with using the oven and getting to know it. They all perform a little differently I suspect.

[strobes]

Re: oven floor temperature - need some data

Yes, I'd expect all perform differently. But common part is temperature of coals. So in ideal situation, when bricks fully saturated by heat, insulation can get close to temperature of coals if insulation is good? But the board I consider is rated to 1200F.

[Tonyp]

Re: oven floor temperature - need some data

I have thermometers in between the insulation and outside brick layer and embedded into the brick about 1/2" from the inside face. I prefer a less intense long burn. My intention is to use the oven for a variety of things for multiple days so I am looking to heat the bricks well.

I have fired the oven up to pizza temperature in 1.2-2 hours but I prefer to do it more slowly and let the heat penetrate more into the brick. Seems to me the carbon really starts to burn off when the brick surface is reaching 750-800F inside face.

My thermometers don't register anything below 400F but even after a couple hours the inside ones are showing some heat but nowhere near the surface temp. recorded by the hand held IR thermometer. and the outer ones are not showing any movement in the temp. dial. 4-5 or so hours later the inner thermometers might be around 600 and the outer ones are starting to read 450-500 roughly. I have not had the fire burning much beyond that so the outer brick surface has only been in the low 500's max so far. And yes the outer surface of the floor does eventually hit the same temperature on the outer dome surface. My floor is actually much thicker than the typical floor so I would guess if you have the thinner 2.25" floor thickness the outer surface will be hotter sooner than the outside dome temperature. It will only get so hot though depending how long you keep the fire going.. I would guess to reach 900 on the outside of the oven whether it was the dome or the floor would take many hours of continuous fire. Could you reach over 1000F on the outer surface of the dome or floor? Sure, I think you could but would take quite a while with a continuous very hot fire..

[kstronach]

Re: oven floor temperature - need some data

in my opinion the bricks won't be fully saturated after 1 1/2 to 2 hours firing even though the dome has cleared and you can cook pizza in it. my dome clears in an hour to an hour and a half but the bricks are no where near fully saturated. for a pizza party i normally burn for 3 to 3 1/2 hours and the top of the inside arch bricks where you can see the full depth of the brick are about 2/3rds of the way cleared or turned white, i find this is a good indication of how saturated the bricks are as you can see the heat penetrating the brick. for a fully saturated oven it might take 5 or 6 hours?

[Greenman]

Re: oven floor temperature - need some data

All of that being said, it is not necessary for the oven to be fully saturated to use it to cook. A couple of pizza don't need a fully saturated oven, just a hot one. If you want to do some retained heat cooking in following days then the benefit of the additional burning time is used.
The beauty of the oven being fully heated through is that it takes very little 'topping up' for subsequent cooks.
Tailoring the heating regime is easier on the woodpile.

[strobes]

Re: oven floor temperature - need some data

Thank you, guys! Very valuable information. And looks like Thermo-12 Gold rated to 1200F under hearth will work fine. http://www.iig-llc.com/pdfs/IIG-300-Thermo-12-Gold.pdf

Tony, what brand of thermocouple wire did you use?

[Tonyp]

Re: oven floor temperature - need some data

Thank you, guys! Very valuable information. And looks like Thermo-12 Gold rated to 1200F under hearth will work fine. http://www.iig-llc.com/pdfs/IIG-300-Thermo-12-Gold.pdf

Tony, what brand of thermocouple wire did you use?

Hi Strobes,

I am using remote bulb dial thermometers instead of thermocouples.