30" castable dome

[david s]

For a 28'-36" diam oven a 6" diam flue is recommended.
For the form of a cast flue gallery, I've made mine well funnelled for good flow and very shallow to make working the oven easier/ I've also made it very thin, note the butresses on the sides for strength, compensating for the thinness of the refractory. The pic should explain.If you cast around the pipe, wrap some cardboard around it that you can remove later so that the expanding pipe has somewhere to move, hence preventing cracking the casting.
https://community.fornobravo.com/for...803#post413803

[UtahBeehiver]

Confirm with DavidS, I think he would recommend a dense refractory for the flue gallery vs an insulating refractory for strength purposes.

[david s]

Apologies, I missed that question. I don't know the compressive strength of the product you are contemplating using, it should be available on the data sheet for it, but even a small addition of a lightweight aggregate drastically compromises the strength of any mix as the table shows. Your dense castable will have a strength of around 2000 psi, many times stronger than the strongest mix on the table. As the flue gallery is required to support the base of the flue pipe and the sides of it are subjected to bumps and abrasion, I don't believe an insulating mix is suitable in the long term.

[gianlucaf]

Ok , thank you both .
will use dense castable about an inch or so in thickness .

[gianlucaf]

Here are few updated pictures.
insulation done, stucco on dome done and today installed granite landing, had some scrap pieces from a neighbor and I cut out the landing.
the curve was not easy to cut, ended up with a nice rough look though.
have had about 3 fires so far. Planning on few more before waterproof stucco layer.