36' low dome neapolitan style

[MarvinG]

Good evening from Tbilisi

I am planning to open a small pizza take away and finally bring some really good original neapolitan style pizza to Tbilisi/Georgia.
Meanwhile I have read through the E-book and know pretty much what I want to build. It should become a beautiful, 36 inch low dome with stucco.
I would not open this topic if there were no questions to remain ;-)

After searching a while I did not find a "well documented" thread about a low dome (neapolitan style).
Is there a well documented thread I missed?
The tuscan style is widespread and well documented. It is said that the low dome is more difficult. I would be curious why.
In my case it makes more sense (since its only about pizza (no turkey & co), its lighter (I will need to move it out of the place we will rent one day) and I like the design somehow more.

It is clear, that it will not only be a wfo, but also gas heated. It offers me a more constant heat, shorter heat up-process, and less work and therefore a lot of convenience. Since I'm not up to experiments I will most likely go with an avanzini drago m1 heater. Are there good/but cheaper alternatives? Or in other words: What are your experiences with the gas heaters on the market? That seems to receive only little attention in the forum.

Another question I wanted to raise is: Many of you use a vent in the top dead centre for/against humidity issue? Somehow I did not understand if I should install one as well, or what kind of trick this thing does.

The whole build will be quite a journey, since the building materials are not so easy to find. But today I found at least chamote mortar, as well as russian fire bricks which look what you guys usually use. The ceramic fibre board I will most probably order online, the vermiculite I will give another try on the local markets. The tile saw as well as the rest will probably also be found. With the double walled chimmney I have to see. The plan is to access a 100year old chimney through a hollow wall which was used to be heated with a fire in the past. Since I have no building codes I am pretty free. It only must make sense and be safe.



Thank you for your thoughts and tipps!
Marvin

[Kvanbael]

Sounds like a great business plan!

A low dome is slightly more difficult, because you can't just use a rigid swinging arm (the "IT") to place the bricks. Instead you need an IT that is adjustable both in length and in angle. So that you can re-calibrate it based on a life-size drawing of your dome cross section.

About the vent in the top: If you want to avoid trouble, just make sure that there's a roof over your oven and that all your dome layers can 'breathe'. Then you don't need it. However... if you're like some of us, and you want that beautiful dome shape under an open sky, then you need to prevent water (rain) from getting in, but allow water (steam) to get out. That's what the vent is for.

[MarvinG]

Hi Kvanbael

Thanks a lot for your answers!!

Sounds like a great business plan!

A low dome is slightly more difficult, because you can't just use a rigid swinging arm (the "IT") to place the bricks. Instead you need an IT that is adjustable both in length and in angle. So that you can re-calibrate it based on a life-size drawing of your dome cross section.

Wouldn't it therefore be easier to build the dome with sand in the middle to have a reference for the right form?

About the vent in the top: If you want to avoid trouble, just make sure that there's a roof over your oven and that all your dome layers can 'breathe'. Then you don't need it. However... if you're like some of us, and you want that beautiful dome shape under an open sky, then you need to prevent water (rain) from getting in, but allow water (steam) to get out. That's what the vent is for.

So If I would like to have stucco (which does not seem breathable for me) would that be a problem? Since my oven will be indoors, I can still forget about the vent?

cheers
MarvinG

[Kvanbael]

Yes, a sand mold is definitely an option. It is not so popular on this forum because it does not let you clean the mortar on the inside. And the symmetry and shape of the finished dome will depend on your sand sculpting skills.

if the oven is indoor then no reason for a vent. Just wait with final render of stucco until after curing fires.

[MarvinG]

Yes, a sand mold is definitely an option. It is not so popular on this forum because it does not let you clean the mortar on the inside. And the symmetry and shape of the finished dome will depend on your sand sculpting skills.

I think my sculpting skills are pretty good. I was thinking of covering the sand with some papier-mâché. (see picture below)


This would the sand prevent to glue. But I don't know if this makes sense. Is it a crucial thing to have very clean gaps on the inside?

And another question came up. The curing fires are in this case done once the dome is built, fireproofe fleece is around, and after the vermiculite layer is applied?
How much time has to pass for each steps? Could I mortar the dome together within one day, and then directly proceed with the next steps? Or in which step do I have to wait how long approx?
Thanks!

ps: just saw the profile pic, your oven looks absolutely fantastic!

[Kvanbael]

Clean joints: As mortar gets more brittle under direct flames, pieces might fall in the food. So you better do some clean-up after removing the mold.

Curing: most people on the forum recommend to cure when all the insulating layers are in place. As also,described in the ebook.

Timing: You can go fast in all steps of the build, but then I would wait at least a week (better 2) before the first curing fire. Not only does a lot of water need to escape, the mortar and concrete in the vermiculite also need time to reach full strength.

[MarvinG]

Great information Kvanbael! They are very helpful!
Today I bought the Russian firebricks (here they are the best quality) Iranians are semi-good I was told. Luckily I also found proper refractory mortar! So I do not need to create my own mixture.
Since I did not find vermiculite, I bought perlite - I guess that ends up the same? To create the last layer of insulation. Do you mix that with refractory cement, or with normal Portland cement?
For the Vent I bough normal bricks, I guess I can also "glue" them together with refractory mortar instead of normal mortar, since I might have more than enough of this?

Cheers
Marvin

[Kvanbael]

Note that most of your questions are covered by the ebook. Not that I mind replying to them (not at all) but there could be other valuable information in it that you are not even aware off.

perlite-concrete (or pcrete) is made with regular Portland cement. Beyond the ceramic blanket (fleece) the temperatures are not that extreme.

Vent with regular bricks: probably ok, but not sure. If you have extra refractory mortar, you can also consider covering the dome with an extra layer of mortar for more heat capacity. For a restaurant, I suppose you can’t have too much thermal mass.

[MarvinG]

Thank you Kvanbael
You know I read it all through but might have missed some points or want to be very sure - you might know the feeling.
I have the bricks at home now - wow, this oven will become pretty heavy ;-)
Have a great day and thanks again for your time!

[Podasols]

Hello,

I'm writing with encouragement about a wet sand former for the dome. I used this for the 36" high dome pompeii that I finally completed last month. It was easy to shape and I cut a plywood template that could be rotated around the sand to check symmetry. As it takes quite a long time to build the dome , I kept the sand dome covered with polythene between work sessions and had to dampen it and repair cracks occasionally. I was careful to avoid too much mortar between the dome bricks where there was a gap - though you do have to fill the gaps. At the end there wasn't too much mortar projecting form the joints into the cavity of the oven and it was possible to knock most of these off anyway.
You need a surprising amount of sand for the former - my 10 x 20 kg bags weren't enough so I actually put in a load of logs and then piled sand on top - packing it in - no problem and the logs weren't too wet at the end.



not sure I've succeeded with the photos.

Good Luck !!

Simon

[MarvinG]

Hi Simon

Thank you for your pictures! I like your encouragement! :-)
Great Idea with the logs!
As soon as I have all the materials sourced I will be able to make the propre plan and keep you posted how it goes!

[Erezj]

Hi Guys, joining the Low Dome inquiries, just finished my hearth and planning next steps.
Simon, did you create any support for the Soldiers? I assume there is much more pressure to knock the soldiers out in a low dome, in many of the videos from Acunto, it looks like there is steel around the soldiers and perlite+cement between the dome and the soldiers to hold them in place.
https://www.youtube.com/watch?v=Z-8vpmgXq1k (check from 3:30)

[MarvinG]

Hi Guys, I'm back after a few days working.

I have bought 80 bricks, 120 of them I let cut in half.
Meanwhile I have planned the sizes and started with the stand and "pan" for the fundament. The thing is, that one day, this oven must be lifted out of a window, 150m cm wide, 70cm high. ;-)
The most challenging so far was ordering the cement fibreboards and plankets, I found a good solution for that in china as well as for the burner. Let's see if it holds what they promised. Otherwise I will change to an avanzini.

Since not all of the fireboard comes on time, (or its just to expensive to transport more by plane) I will do the following:

5cm of Perlite & cement, 5cm of fireboard. And also around, 5 cm of planket, 5 cm perlite-cement. The rest we will see.
Is it easy enough to cut all bricks with a angle-grinder with the diamond blade, or ist that a stupid idea?

[MarvinG]

here some plans and pictures

[MarvinG]