Corner Pompei Oven following Forno Bravo instructions-Loei Thailand

[Garouda]

Hi there,
Good to see there are other projects around here.
I'm a Belgian living in Thailand since 2003, first in Chonburi where I worked until I retired in 2017. My wife comes from Loei, so we decided to settle in her village, uphill outside the village in fact. The first purpose of that project of pizza oven is to bake bread, and hitting two birds with one stone, also pizza and other foods using the remained heat.
The size of the oven will be Ø 40 inches. I built the foundation two years ago because we were going to pour concrete in the yard in front of the house. The base has just been built by people from the village. I had two walls built because you don't find big concrete blocks here. I'm afraid, I will have to build the rest by myself because it's a technique that neither they nor me are aware of. The next step will be the laying of the vermiculite floor, 4 inches thick. I found a factory of refractory products in Prachinburi and I will go myself to look for the refractory bricks, the refractory mortar as well as the clay for the laying of the refractory bricks of the bottom.https://motproduct.com/%E0%B8%95%E0%...%E0%B8%B2.html I get a lot of inspiration from the videos made by Artisan Made.
https://www.artisanmadethings.com/brick-oven

[Garouda]

Some more pictures

[Garouda]

I used the spreadsheet designed by Denis aka deejayho https://community.fornobravo.com/fil...etch?id=319989 according to that nice calculator I would need some 150 bricks for the dome and 34 for the floor. I may drive tomorrow to Prachinburi to get my materials. If I calculate the surface of the dome and divide it by the surface of a brick, I come up to a very close result : 23,610/78.8=299, so 300 half bricks or 150 bricks (half a dome S = 2 Πr ² REM I calculate in cm)

[UtahBeehiver]

Be sure to add some contingency for oops, perhaps 5%

[Garouda]

Be sure to add some contingency for oops, perhaps 5%

Indeed, also for broken bricks, the bricks I found were not top quality, so I ordered 250 of them, and they topped up with another 20 bricks...
Price USD 0.29 each, refractory mortar 25 kg bag : USD 7.35...
I had to drive through the mountains with a load of about one metric ton on my Ford pickup...
Last Friday, we left home at 1:20 a.m. arrived in Ang Thong at 9:30, and came back home at 20:30... a round trip of 1020 km...
I initially planned to buy them from a factory in Prachinburi, but they were still cooling down in the oven, so I went to another factory of the same company, in Ang Thong, between Singburi and Bangkok.

[Garouda]

At this stage, I have two questions :
1. I tried to find the design of the floor pattern for my vermiculite insulation floor, got many pictures, but no real template.
2. All the posts are opposing vermiculite against ceramic fibre board, what about cellular concrete?
Vermiculite: coefficient of thermal conductivity between 0.08 and 0.09 W/m.K.
thermal conductivity coefficient of cellular concrete goes down to 0.09 W/m. K, very close to vermiculite. Cellular concrete can easily be cut with a hand saw.
Anyway, I'll go for vermiculite for one good reason, I already have it on hand, but I'm wondering whether I could use cellular concrete as thermal block between the floor and the landing.
I did not use any formwork for the base of the oven, but the slabs that I had left over from the construction of the house. I didn't think of it, but I could have integrated two thicknesses (2x7cm) of cellular concrete blocks into the concrete using the few blocks I had left. Furthermore, I have a handsaw for cellular concrete and I could easily have cut these blocks, straight, no curves, which would have avoided me building the formwork of the base in vermiculite. 14 cm of cellular concrete instead of 10 cm of vermiculite would even have provided a better insulation. In addition, I would have gained 4 cm in height... Regrets are sterile, but I write this to share my thoughts.

[UtahBeehiver]

I am not sure what post are showing not to put ceramic board against vcrete. A 5 to1 Vcrete (min 4") first (against concrete slab the topped with CaSi board would be great, or all v-crete. Hebel which is an aerated concrete has been used a bit by our Aussie builders as a base layer. I am not sure how much heat Hebel or aerated concrete can handle though.

[Garouda]

I am not sure what post are showing not to put ceramic board against vcrete. A 5 to1 Vcrete (min 4") first (against concrete slab the topped with CaSi board would be great, or all v-crete. Hebel which is an aerated concrete has been used a bit by our Aussie builders as a base layer. I am not sure how much heat Hebel or aerated concrete can handle though.

Anyway, it's too late for cellular concrete blocks (aerated concrete), I just wanted to share my thoughts...
I'll go for 4" vermiculite.
Any hint about the build of the form work? I searched the forum but could only find pictures, some are well detailed though. Your project(s?) look very professional indeed!

[UtahBeehiver]

Square or rectangular shape, just dimensional wood form, circular, landscape bender board. Be sure to install weep holes in the concrete hearth, especially since you are in a tropical area.

[Garouda]

..Hebel which is an aerated concrete has been used a bit by our Aussie builders as a base layer. I am not sure how much heat Hebel or aerated concrete can handle, though.

Autoclaved aerated concrete provides the highest security against fire and meets the most stringent fire safety requirements. Due to its purely mineral composition, AAC(aka Hebel here, Ytong in Europe after the name of the Swedish village where that process was invented in 1938?) is classified as a non-combustible building material. It is both resistant to fire up to 1200 °C and, unlike other construction materials, heat-resistant.
Source: https://eaaca.org/fire-resistance/
And, as I wrote earlier, AAC offers almost the same heat resistance as Vermiculite...
But for me, it's too late, I'm going to build that insulation part of the hearth in vermiculite like here: https://youtu.be/v-neyYcCmU4
My concern about that video is that the first template he shows at the beginning of the video is longer that the one he actually uses in the end.
I this a correct drawing (see picture)?

[Garouda]

Anyone has an oven floor template for a 40" oven? I'd need drawing plans to build the vermiculite formwork for the floor.
I've seen some differences on the templates, and not sure why some have straight openings and some have a bit of a diagonal opening.
Any thoughts?

[david s]

I used Hebel Power Panel for the supporting slab for my mobile oven in the belief that it would be both strong enough as well as acting as sufficient underfloor insulation. It turned out not to be, but I think it's probably ok in a stationary situation.
See here
https://community.fornobravo.com/for...ion#post398266

[Garouda]

I used Hebel Power Panel for the supporting slab for my mobile oven in the belief that it would be both strong enough and acting as sufficient underfloor insulation. It turned out not to be, but I think it's probably OK in a stationary situation.
See here
https://community.fornobravo.com/for...ion#post398266

Thank you for the link, anyhow, I thought about it too late, I have already poured my concrete slab. In my case, there are anyway prefabricated slabs which I used as formwork and which would have supported the blocks of autoclaved aerated concrete, which we call Ytong in Europe because that brand is the name of the Swedish village where the process was invented in 1938 if I well remember.
I found a project that is more or less in line to what I would have done, but with two layers of 7 cm blocks, he uses 5 cm blocks which IMHO is too thin. I would have used 15 cm blocks, but we can hardly find them in my remote province of Loei, in the NE of Thailand, 40 km from the Mekong River…
https://community.fornobravo.com/for...-build?t=14444.

[Garouda]

Next step, the formwork template it's frankly speaking too hot to work outside now, even in the shade. Normally in this period of the year we have rain, but the seasons have hanged.

[Garouda]

The vermiculite has been delivered, the formwork is done, I took the cuts from the floor template to hold the circle in place and four wooden planks locked with four F-clamps made a frame to hold everything in place. I bought a tent for both sun and rain. I got short of vermiculite... I calculated a volume of 150 litres, but the two 100-litre bags were not enough, they seem to have a different definition of the litre down here...
Total volume: 71 cm x 43 cm x 10 cm = 30530 cm3 and 123 cm / 2 at the power of 2 x 3.14159 x 10 cm = 118823 cm3 : total 150 212.8 cm3 or 150 litres... A piece of advice, take some empty beer bottles you must have somewhere in a corner, break them in small parts to have about a 1/2" layer, and you won't risk being facing the same issue with your vermiculite. I did not consider that problem and of course, I'm not going to put glass as first layer under the refractory bricks...
Breaking News... I checked the website of that company, they also sell 60-litre bags, in other words the seller on the online shopping channel cheated me and sent me 60-litre bags for the price of 100-litre bags!