Insulating Firebricks

[Johnny the oven man]

Originally Posted by Karangi Dude

The one thing about insulating fire bricks is that they do not expand with heat anything with Portland cement has a tendersy to move with heat causing cracking in what is built on top of it. You need to have a floating floor and build your dome on that in other words don't mortar your first course to the vermicrete. I also beg to differ on the insulation qualities of the Insulation Fire Bricks if Vermicrete is as good, they would certainly use it in furnaces but they don't.

Doug

Vermiculite IS used extensivly in furnaces as an insulation product. It is used in both sheet form and loose fill.

[GianniFocaccia]

A UK firm (Vitcas) manufactures vermiculite board as insulation and strangely enough, firebrick replacements in wood stoves. Rated to 1000*C, I think this board is a little overkill for our application but the fact that we can manufacture such a cost-effective
insulative layer from common materials purchased from our local box store is way cool.

[Karangi Dude]

I don't have a problem with vermiculite it is the cement that is used with it.

Johnny the oven man;108779]Vermiculite IS used extensivly in furnaces as an insulation product. It is used in both sheet form and loose fill.

Yes it is but not with cement mixed with it!

As a matter of fact I am using vermiculite as a loose fill on top of 2 layers of insulation blanket in my enclosure.

[david s]

"Vermiculite is rated well over 1000f, in fact it is exfoliated at 1200c,"
The exfoliation is done at around 540 C- 810 C, but still well over the 1000 F

[Karangi Dude]

We know that vermiculite is well rated but what about the cement that is used in the mix.

[brickie in oz]

Ppl seem to get so anal about all the what ifs?
Just go and build the thing and enjoy the benefits of a WFO.

[Karangi Dude]

Hey Brickie,

I agree!!!!!!!
Some like myself used Insulation Bricks some used Insulation Board others used Vermiculite Mix it does not matter as they all work. The main thing is we are building WFO"S that we can share with our Famliy and Freinds. I think there has only been one oven that collapsed on this site dew to moisture or something that's a pretty good average.
Brickie I like your new Avatar and that's is a very kind gesture of yours to go help out in Christchurst NZ that's the Aussie spirit.

Regards Doug

[dmun]

Some like myself used Insulation Bricks some used Insulation Board others used Vermiculite Mix it does not matter as they all work.

Amen. If we start spreading the word that the only good solution is the difficult, expensive solution, we may discourage potential builders.

[Neil2]

The vermiculite mix has been used by literally hundreds of builders on this site with success.

It is cheap and easy. I'm convinced it is the best solution for the DIY builder for the under hearth insulation. The FB board insulation also works well and for some may be the solution since it doesn't involve the formwork, pouring and leveling that the vemicrete requires.

[Johnny the oven man]

Originally Posted by Karangi Dude

We know that vermiculite is well rated but what about the cement that is used in the mix.

Use cement fondue, a high temp. calcium aluminate product from a company called Kerneos.