Mortaring

[TCPizza]

Should I mortar the first chain to the firebrick floor of the oven.

[Toneer]

Re: Mortaring

I am not an expert in oven building, so also consider other suggestions. In my opinion you have to mortar it down since you need an air tight seal around the paremetar of the 1st chain.

I also have a question: How much mortar do you apply for the flooring?
How much joint space should be left on flooring (if any)? And the same question when doing the chain?
Thanks

Should I mortar the first chain to the firebrick floor of the oven.

[deejayoh]

Re: Mortaring

No, you don't need to mortar the chain to the floor. You don't need an airtight seal and the weight of the dome will hold the brick in place. You do need to mortar the bricks together on the sides. Shoot for a 1/8" joint spacing - but know that the gap will be wide at the back unless you are tapering your bricks.

Floor bricks should be pushed together as tightly as possible and do NOT use any mortar!!! Set them in sand/fireclay mix as per the instructions.

[stonecutter]

Re: Mortaring

Should I mortar the first chain to the firebrick floor of the oven.

No need, it will break bond within the first couple firings.

[texman]

Re: Mortaring

ditto stonecutter and DJ-sides only.
texman

[mrchipster]

Re: Mortaring

I am not an expert in oven building, so also consider other suggestions. In my opinion you have to mortar it down since you need an air tight seal around the paremetar of the 1st chain.

I also have a question: How much mortar do you apply for the flooring?
How much joint space should be left on flooring (if any)? And the same question when doing the chain?
Thanks

If oven dome is placed on the floor it should just set on the floor.

If floor is cut so as to fit inside the oven dome ther should be a 1/8 - 3/16 gap created by wrapping the floor in a layer of corregated card board to allow the floor to expand and not crack the dome. The void. Left by the cardboard will burn out and fill with ash. Tape over the cardboard with masking or duct tape to prevent mortar from falling into the gap

[Toneer]

Re: Mortaring

If oven dome is placed on the floor it should just set on the floor.

If floor is cut so as to fit inside the oven dome ther should be a 1/8 - 3/16 gap created by wrapping the floor in a layer of corregated card board to allow the floor to expand and not crack the dome. The void. Left by the cardboard will burn out and fill with ash. Tape over the cardboard with masking or duct tape to prevent mortar from falling into the gap

Now I know why the dome is not mortared to the floor. It needs to freely expand and contract.
What exactly should I lay the floor on? I know it's some kind of sand mixture, will I be able to buy it from a local home depot or building supplier?
Also I have heard that broken glass is a good heat insulation, is this true?
If yes, can I cover the dome and the base foundation with broken glass for heat insulation?
Thank you!

[mrchipster]

Re: Mortaring

Now I know why the dome is not mortared to the floor. It needs to freely expand and contract.
What exactly should I lay the floor on? I know it's some kind of sand mixture, will I be able to buy it from a local home depot or building supplier?
Also I have heard that broken glass is a good heat insulation, is this true?
If yes, can I cover the dome and the base foundation with broken glass for heat insulation?
Thank you!

SAND IS NOT AN INSULATOR!!!!!!!! and broken glass is almost as bad.

The best product for insulating under the floor is CalSil board or ceramic board.

Many people use a mixture of Portland cement and either vermiculite or perlite.
This is not as good an insulator as ceramic board but will be far superior to glass or sand.

There is also a product called Foamglas that works very well also.

Please do further reading on this site before starting your oven you will be happy you did.

If you decide to use perlite or vermiculite with Portland cement you will want a 5-1 or 7-1 ratio of vermiculite to cement. Make note I said cement NOT concrete or sand mix.

The tandoor oven is something I am unfamiliar with and my comments relate directly to pompellii or dome ovens and my not be advised for a tandoor oven.

[stonecutter]

Re: Mortaring

Now I know why the dome is not mortared to the floor. It needs to freely expand and contract.
What exactly should I lay the floor on?
You can use a mixture of fireclay/sand or even a very thin layer of sand.

I know it's some kind of sand mixture, will I be able to buy it from a local home depot or building supplier?
Masonry supply yard will have fireclay or if you have a wetsaw, cut your brick for the dome and then use the slurry that settles in the tray

Also I have heard that broken glass is a good heat insulation, is this true? No...glass bottles are marginal, but they need to be encapsulated in a non combustible material, like clay. More efficient insulation would be vermiculite or perlite mixed with portland, ceramic fiber or mineral wool board insulation.

If yes, can I cover the dome and the base foundation with broken glass for heat insulation?
See above

Thank you!

Hope that helps.

EDIT: I was typing as the above was posted. Redundant but true (my post).

[Toneer]

Re: Mortaring

It helped a lot.. Thank you very much!
I am planning to build an Armenian underground oven (tonir). There is a youtube video link below, which will give you and idea. And to build it I will use Italian pizza oven technology. The oven by shape is 35-47" tall wine barrel with 24" diameter (opening).

Is there a specific type of sand I would want to use for the flooring?
What do you think what kind of insulation should I use for the oven, that's both effective and cost efficient?
Thanks again!

https://www.youtube.com/watch?v=qkfcO_Pz0cY

Hope that helps.

EDIT: I was typing as the above was posted. Redundant but true (my post).

[stonecutter]

Re: Mortaring

So it is a Tandor oven that you wish to built with brick?

If it was me, I would use splits and rip them into pieces like 2"x2"...the Tandor (Tonir) is going to have a much,much tighter radius than the dome or barrel vault. The smaller shapes will help you maintain a neat radius.

The 2"x2" is just a guess, but the smaller the Tandor ( or oven for that matter ) the harder it is to keep a nice radius with larger units.

You can use bagged play sand or mason sand...you are only using a thin layer above the insulation remember.

[stonecutter]

Re: Mortaring

Also, if your oven is to placed underground, you now have to contend with moisture problems in your insulation.

Make sure you use a water proof membrane or heavy plastic between your insulation and the surrounding ground.

[Tscarborough]

Re: Mortaring

I am not sure that you can use firebrick for a tandoor/tonir. They are normally made of terra cotta which has different thermal properties.

[Toneer]

Re: Mortaring

Some history of tonir:
Tandoor is Indian version of tonir. The first Tonir type underground ovens were discovered in Armenia that dates back to 3000BC. The oldest winery and shoe was also discovered in Armenia. Scientists discover 'oldest' winery in Armenian cave - CNN.com

Armenian traditional tonirs by size and shape are very close to the size I already mentioned (24" diameter, 35"-47" height or taller and the shape is of a wine barrel). Originally it is a large fireproof pot that is insulated and buried underground. Since it's very difficult to find a quality pot, some masters build it from firebrick.

So it is a Tandor oven that you wish to built with brick?
Yes, that is correct (tonir oven)
If it was me, I would use splits and rip them into pieces like 2"x2"...the Tandor (Tonir) is going to have a much,much tighter radius than the dome or barrel vault. The smaller shapes will help you maintain a neat radius.

The 2"x2" is just a guess, but the smaller the Tandor ( or oven for that matter ) the harder it is to keep a nice radius with larger units.
I was thinking about 2x2 too. Do you think medium duty firebrick (9x4.5x2.5) is good choice for this project? do you think cutting the bricks with brishblaster (chisel) is a good idea?

You can use bagged play sand or mason sand...you are only using a thin layer above the insulation remember.

[Toneer]

Re: Mortaring

I am going to compact the soil and lay the heavy plastic then gravel, sand and on top of that concrete foundation (base), I will do the same with the sounding walls. And build my tonir in that box and fill the sides (in-between tonir and the box) with some type of ceramic fiber insulation.
What do you think, is it a legit plan?

Also, if your oven is to placed underground, you now have to contend with moisture problems in your insulation.

Make sure you use a water proof membrane or heavy plastic between your insulation and the surrounding ground.