Cooking floor

[JordanWelborn]

hi all, new here.
Im about to embark on a casted WFO.
I plan on using Ciment Fondu / vermiculite with SS needles for reinforcement.

Firstly, is it possible to complete a layer of CF mixed with firebrick grog, followed by a layer of CF with vermiculite?

back to the original question - I have some old engineering bricks (dense Victorian bricks) that I planned to have as my cooking floor lay above a vermiculite insulating Mayer.

My my question is, could I have a CF slab atop of the bricks as my cooking floor?

any advice, tips or redirection would be extremely well received!

Thanks all.

[fox]

Hi, I am a bit confused ...CF = high temperature cement?
The cooking floor is a very important aspect and personally I prefer new fire bricks as they are so well tried and tested, easy to replace should one crack (unlikely) , flat and smooth and hold the heat for long periods.
Yes you can cast a cooking base but best not in one piece and best to have it vibrated with a proper tool.
under you chosen cooking base, you will need an insulating layer, vermiculite is fine although the less cement the better it will insulate, but the weaker the mix the less strength it will have.
The mix ratio can be depending on your overall design and how the layer is retained but 6-1 or 8-1 is possible however ... ceramic fibre board is what I much prefer to use.
You don’t need to mix the vermiculite with high temp cement, you can use it if you want but beware it sets very fast!
under you insulating layer you can use a standard 6-1 concrete mix.
We would need to see some form of plan to give really accurate answers though.

[UtahBeehiver]

I suggest you reach out to David S from Australia, he is our casting expert and can give you great guidance. He does cast ovens commercially.

[fox]

So do I but never mind I will get my hat!

[david s]

hi all, new here.
Im about to embark on a casted WFO.
I plan on using Ciment Fondu / vermiculite with SS needles for reinforcement.

Firstly, is it possible to complete a layer of CF mixed with firebrick grog, followed by a layer of CF with vermiculite?

back to the original question - I have some old engineering bricks (dense Victorian bricks) that I planned to have as my cooking floor lay above a vermiculite insulating Mayer.

My my question is, could I have a CF slab atop of the bricks as my cooking floor?

any advice, tips or redirection would be extremely well received!

Thanks all.

Ciment fondue and firebrick grog is not as good as as firebrick for the cooking surface. There are two problems, the first as Fox has pointed out is that any large casting has a greater chance of cracking due to the rapid and uneven heat applied to from a fire sitting directly on its surface. This is the main reason cooking floors use smaller units, laid loose to allow for uneven expansion.Secondly , castings made with calcium aluminate cement (cement fondu) should be fired carefully in a kiln to 1000 C to attain their full strength. This is not possible for a cast in place WFO floor or dome. It is sufficient for the dome, but the floor takes an extra beating. A better material would be a proprietary castable refractory as it contains other ingredients that make it superior to CF/ firebrick grog, but still unfired in a kiln and not as good as the firebrick. The engineering bricks are a possibility and could be suitable , but they also might fail as they are not made for the purpose. You could try them laid loose and replace them with firebrick if they fail. Your intended mix of CF and vermiculite is a poor choice for the dome as it creates a casting with little strength or the required thermal mass.