New idea for thermal break??

[WJW]

What about this stuff...it's a Harbison Walker product. It comes in a caulk tube or a tub. It seems like you could use this to isolate the entryway from the oven...and it's durable enough for hotface insulation!

Here is the description from the the HW webpage.:

Moldable

INSWOOL MOLDABLE is a 2300°F ceramic fiber, putty-like consistency material, used for linings up to three inches thick, to pack large voids, or even fill thin cracks. It can be troweled or hand packed into place.

INSWOOL MOLDABLE is light weight, with very low thermal conductivity, and therefore a good insulator, yet it develops a strong hot face surface to withstand physical abuse and high air velocities as compared to conventional ceramic fiber products. It is also used as a high temperature gasket material, and as a general purpose patching product. Its ability to compress makes INSWOOL MOLDABLE an excellent material for expansion joints and for filling contraction cracks. It is also an ideal material to fill ceramic cuplock anchors for ceramic fiber blanket linings, and can be used in contact with molten aluminum.

INSWOOL MOLDABLE has excellent thermal shock resistance, and can be dried or put into service immediately with no pre-heat required, with the exception of direct molten metal contact. Then the INSWOOL MOLDABLE should first be thoroughly dried, and fired, to remove all mechanical water the entire depth of the material, to avoid dangerous steam explosion.

Pumpable

INSWOOL PUMPABLE is a 2300°F ceramic fiber, putty-like consistency material, especially formulated for pumping with special equipment. It is usually used for pumping behind existing hot face linings for insulating purposes; however it can be used to fill small voids and thin cracks.

INSWOOL PUMPABLE is a light weight material with very low thermal conductivity, and therefore a good insulator. It dries to a firm, board-like consistency, for good sturdy integrity. Its ability to compress makes it ideal for expansion joints, and for filling contraction cracks. In addition it is used in contact with molten aluminum.

Although normally used as a backup material for hot spots, as mentioned above, when used as a hot face material, the INSWOOL PUMPABLE has excellent thermal shock resistance, and can be dried or put into service immediately with no pre-heat required, with the exception of direct molten metal contact. Then the INSWOOL PUMPABLE should first be thoroughly dried, and fired, to remove all mechanical water the entire depth of the material, to avoid dangerous steam explosion.

http://www.hwr.com/images/inswoolmoldable.jpg



Edit: Just called and got a price...$38 for the one gallon tub of the moldable putty.

[Gulf]

Thank's for the post.
That is definately interesting to me. I hope to do some research on this myself when I get time. Anyone with info about this product and it's suitability to food preperation would be greatly appreciated.

[Karangi Dude]

Hi Guys,
IMO I think far to much is put into the fact that a thermal break is needed.
The hearth and entrance of my oven (outside the door arch) gets hot mainly due (99%) to radiant heat, a 1/2'' or 2'' heat break will not make one bit of difference when you have a raging fire going inside the oven the entrance is going to heat up from radiant heat and will not wick heat away from the oven and will maintain heat long after the fire is put out.

I also believe that the flue, the flue chamber and the flue exit need to get nice and hot to create good draw

Just my thoughts Guys (from my experiences)

[Lburou]

What Doug says has a lot of merit. At the same time however, I added the thermal breaks for cooking two or four days after the fire has been out. The thermal break is absolutely not necessary, but, nice to have

WJW, I would have tried the product you describe, but its too late now.

Doug plays his oven like a piano, I just have a bell in comparison.

[Karangi Dude]

Hi Lee

Thanks, but I think you are far to generous with your praise and you are far to hard on youself.
Remember I have been cooking for more than 40years and to me a WFO is just another heat source for cooking and like all types of heat sources you need practise to get things right.
As you know Lee I also cook for many days after my fire is extinguished, that is made possilbe by two things heat saturation of the oven and good insulation under and around the oven.
There is one place that a thermal break could have merit and that is between the vent arch and the decorative arch, if you are using two different brick types such as firebrick for the vent and whatever brick you use for the decorative arch, the two types of bricks might expand at different rates and cause cracks in the decorative arch.

[brickie in oz]

The heat break that I built into my oven definitely works, you can feel the difference as the front arch doesnt get hot, not like the last oven did.

Ive also taken infra red readings and there is a real difference before the insulating fire bricks and after.

The entry floor gets hot but I didnt really incorporate a heat break there, well, only a half arsed attempt.