Thermal Break Materials

[BothellOven]

What materials have people used to create a heat break between the oven dome floor and the landing floor?

[david s]

Re: Thermal Break Materials

You can just leave an air space, but it will fill with ash and debris. Some folk have used insulating fire brick, although this does not have any flexibility to allow for expansion stresses. You could try a high temp caulk, I prefer to use a vermicrete mix.

[Neil2]

Re: Thermal Break Materials

I used a one inch break the width of the opening. This funnels down through the insulation layer to a four inch diameter hole through the structural slab and thus also functions as an ash drop.

I used a layer of insulating brick for the sides of the opening and the vent funnel is the width of the opening at the top forming the thermal break there.l

[Lburou]

Re: Thermal Break Materials

My floor brake is shown below. An infra red thermometer shows about 50-75 degrees F difference between the firebrick entry floor and the granite you see in the third picture (temperatures range with the stage of the firing).

Below, you see about a 1 1/2 inch gap where the insulation touches the base which will hold the strip of granite. I filled that space with rigid insulation and put the granite over it, leaving about an eighth inch air gap between the firebricks and the granite. I'm happy with it.



I'm in the process of brushing ash in that crack every time I get a chance (ash is supposed to be insulative).

[SCChris]

Re: Thermal Break Materials

I cut a piece of 2" rigid insulation to just shy of the thickness of the brick floor, 22 inches long by 2 inch by 2 3/16ths. I then ripped, removed, a 2cm by 1 1/2 portion to create a recessed landing to support the entry granite and still maintain a 1/2 break between the entry granite and brick floor of the oven. Like a lazy L. The break runs the full width of the entry, 22 inches, and the door sits directly over the break and extends into the entry.

Chris

PS That unlabled polygon is also rigid insulation, like the labled block that it sits on. The unlabled rectangle is a firebrick in the oven floor. Sorry I'm very weak on sketch..

[gmchm]

Re: Thermal Break Materials

So, what if the rope insulation used in wood oven doors is used to fill an air space of say 3/8 inch? My wood stove reaches temperatures that burn off all the carbon inside the stove. I assume this correspondes to the dome clearing temperatures. The rope seems to be inaffected buy this. The fact that there is a small area filled with ash does not bother me much.

[SCChris]

Re: Thermal Break Materials

Gmchm,

I think the rope would be fine as long as it isn't where it'll get any abrasions from pots and pans going in and out. What I liked about the rigid insulation was the dimensional stability the ability to define how it sits in the space. I saw the product being fabricated, in essence milled at the foundry service and suppler, and felt that as long as the floors were a bit higher than the R.I. and the gap wasn’t too wide this was a permanent solution or nearly so.

Chris

[Tscarborough]

Re: Thermal Break Materials

The rope is woven of glass, FYI

[gmchm]

Re: Thermal Break Materials

Is that good or bad?

[david s]

Re: Thermal Break Materials

I wouldn't think loose glass fibres stuck to the bottom of your pizza could be healthy.

[gmchm]

Re: Thermal Break Materials

I agree, but I don't think they will be anywhere they would touch the pizza. Actually, with the airspace, I could probably do without the insulation, as you suggested earler.