Help ...Clay oven design

[martynw]

never posted on a forum so hopefully this will be of some use.

I need some advice as I am building an oven but have no practical knowledge, skills or experience.

I want to make a clay oven that is well insulated to enable both fast (I.e pizzas etc) and slow cooking ( would like to be able to do overnight cooks with meats).

I have a rough plan but need a bit of guidance as to whether this all sounds good.

THE BASE/PLINTH
I have started building this and was following a plan for a cube base made of sleepers with a cavity filled with hardcore then a layer of glass bottles and topped off with 25mill Fire bricks, I thought about adding in a calcium silicate board layer here somewhere for additional insulation.
I have an alternative plan which doesn't have the massive cavity but will only leave 75mil under the firebricks which I could fill with sand and a 50mill calcium silicate board.
-which of these will offer the best insulation? The second plan has the advantage of me not having to fill a 1meter cubed cavity with hardcore and also allows a space for logs to be stored underneath.
Advice very welcome...?

FIRST LAYER
I intend to make the first layer out of clay/sand mix over a sand dome with a brick archway opening, allowing space between dome and arch for a chimney.

INSULATION LAYER
I intend to wrap a fire blanket around the dome with chicken wire then a thin layer of vermicrete mix over the top.

TOP LAYER
I have some lime hydraulic mortar left over from re-pointing my house, I hope I can use this as a final water resistant sealing layer, this is ready mixed so I might need to add more sand maybe??

I would love it if some of you experienced people could give your thoughts on whether the above sounds practical???

P.s I know I've posted this in three different threads, is that frowned upon? Sorry if it is!

[oblertone]

Martyn, welcome to the forum, please note I have deleted your duplicate threads to keep the place tidy, and to concentrate any advice you do get.

As to your proposed build plan, personally I'd go with the increased Calsil board rather than hardcore and bottles because underfloor insulation is one thing you need to get right from the start; secondly finding and moving a cubic metre of rubble is too much like hard work. 50mm of board under firebricks will be plenty of insulation.

I have no experience with clay domes (yet) but your proposed plans seem fine to me. Try to ensure that your floor doesn't extend beyond the dome walls, and that whatever dome insulation you use makes contact with the underfloor insulation and you'll be fine.

Once you start building, take plenty of pictures and start your own build thread, but before you commence please read some of the other build threads to avoid common mistakes.

Regards and good luck

[martynw]

Hey

Thanks for your help! I took your advice and went for the second design.

Where is the right place to start the thread, I'll put some pictures up.

I've noted your comments about only having the oven floor under the dome not the whole of the space, any ideas what I can fill the remaining area with as the cal sil board will look a bit rubbish I guess, and won't be level with the top of the plinth.

[oblertone]

Search through the drop down menu to find the appropriate forum for your build thread, although it doesn't matter that much.

As to covering exposed Calsil; wait until you've insulated the dome before doing anything as this dome insulation should contact the Calsil to encapsulate your dome most efficiently., then the choice is yours. I tiled over the exposed bed using waterproof tile cement, others have used slate or marble offcuts, house bricks cut in half, or just filled in with the dome render.

[martynw]

Cool I've started a thread here

link