36" build in heart of Europe, Czech Republic

[flatfourfan]

Nice build......liking those temperatures!!!!

[mrotter]

https://imgur.com/a/YkezVwq

[mrotter]

OK, guys, after series of well-crafted curing fires, I obtained some dry hardwood and pushed oven to 500 C (1000 F) in all inner parts of the dome. Dome got way above 500 C, floor to 460 C and higher. Stainless steel chimney did magnificent job, no cracking so far anywhere. Baking long-baked meat/potatios in iron pot.

[Honcho123]

Dobry, awesome oven

[mrotter]

Great, you’re now ready to start slowly driving out the oven moisture. Try not to get too much flame impingement on the dome. The 7 fires in 7 days method with the fires getting progressively bigger works pretty well.

Yes, I already made 1 very small fire, and one side test. I plan to light fires each day, for maybe 10 days. I still wait for some chimney parts which must be installed before I make larger fires, otherwise I risk damages to my terrace roof.

As a side test, I bought laser gun thermometer. I fired small fire on some extra firebricks and made some saussages on it. The fire was quite small, no big chunks of wood, it flamed for around 30 minutes. Then I measured temperature of bricks and I was just stoned. Top side of bricks was 200C, bottom side about 120C. I already smell the pizza guys.

[david s]

Great, you’re now ready to start slowly driving out the oven moisture. Try not to get too much flame impingement on the dome. The 7 fires in 7 days method with the fires getting progressively bigger works pretty well.

[mrotter]

OK, I kept my concrete enclosure moist/covered for a week. I used reinforcing fibres, also top plug to let moist come out during curing/drying process. See photos.

Also, there is 15 mm gap between concrete shell and vent arch, to have trully lone-standing vent arch. This will be covered by heat resistant rope after top rendering is done.

[mrotter]

Spraying the surface infrequently is far less successful than keeping it constantly wet for damp curing. A superior method is to wrap the whole thing in cling wrap so it’s sealed up. Keeping this on for at least a week enhance the strength considerably.

Yes, I know, I have it covered all the time, especially in this hot weather.

[david s]

Spraying the surface infrequently is far less successful than keeping it constantly wet for damp curing. A superior method is to wrap the whole thing in cling wrap so it’s sealed up. Keeping this on for at least a week enhance the strength considerably.

[mrotter]

It is best to do all of the drying fires before any outer render layers are applied. Otherwise any moisture left in will be much harder to eliminate. 1.5” (40mm) thick render is very thick, I only do mine 10-15 mm with random AR glass reinforcing fibres. The outer shell is only a weather protection and to stop damage to the insulation.

I did basic render yesterday. The brick and mortar was really really dried out, trust me, it stayed on hot sun for weeks, covered for rains.

As for render, maybe it is wording thing, but it is rather "concrete enclosure/shell", there will be one extra thin layer of silicone-based coloured render. I had some real bad luck yesterday as I was interrupted TWICE by rain and had to work hard to finish job, I ended in 23:59 MIDNIGHT!!! As for thickness, I believe I ended on average between 2-2.5 cm, some spots likely have thinner layer of concrete, around 1 cm maybe. If I used some special stucco material, I could likely go with thinner shell, but with pure concrete I feel the thickness is just about right. I also used reinforcing fibres, seems to work really nice.

As for moisture, during rendering I installed plug which can be opened at the very top of dom and I will have that opened during drying/curing process, but in overall, I do not believe I will need many extra curing fires. I will let it sit for two weeks now and likely apply concrete hardening solution (sprayed aerosol) to increase strength. Will provide photo soon, so far no cracking, my wife got order to keep the concrete covered and spray it with water each 2 hours.

Also, just ordered SS chimney system pieces.

[david s]

It is best to do all of the drying fires before any outer render layers are applied. Otherwise any moisture left in will be much harder to eliminate. 1.5” (40mm) thick render is very thick, I only do mine 10-15 mm with random AR glass reinforcing fibres. The outer shell is only a weather protection and to stop damage to the insulation.

[mrotter]

Insulation on. Btw, even this unfinished chimney IS DRAFTING smoke just fine. I was shocked to see that even this semi-done chimney works good. Smoke went through chimney and not front.

First fire: https://www.youtube.com/watch?v=63QX_ecgWSM

[mrotter]

OK. I applied 3 layers of blanket, 3" in total. I am about to apply concrete render of about 1.5" thickness.

I already laid two courses of brick chimney, will be ordering stainless steel single wall chimney system which will come on top of it.

Also, made first curing fire yesterday and even incomplete chimney of about 30 cm length DID draw smoke out of vent arch! Huge satisfaction.

Will post photo/video soon.

[mrotter]

OK, made progress. Built vent arch, which is free-standing. All surfaces of vent arch which are facing to main oven dome are separated with 1-2 cm of space which is now filled with blanked insulation. There is very big heat brake gap incorporated into floor, also filled with blanket. All sides of floor are separated from vent arch also with insulation blanket (1 cm) covered by thin layer of sand.

Prepping for blanket insulation covering of dome. Dome/vent intersection will be separated by fire-resistant elastic rope.

Insulation will have 7 cm (3 layers) + 3-4 cm of concrete shell on top of it. Then top finish which will be silicone-based render normally used for houses here. Vent arch will be covered by "flexible" mortar and broken mosaic-like style tiles.

As for flu, I am about to order 150 mm ID metal chimney pipes which will be placed in square-shaped chimney brick structure.

After blanketting, I plan on doing some small fires, but overally there is little to no of moisture in the oven as it was left uncovered in shiny weather and covered during rains.

I plan to make/buy some small decorative statues to be placed on those two small platforms in the front face of vent arch.

[mrotter]

Anyway, I went with 3-piece keystone, stones places side by side. Also, I decided to make cuts into casi to make room for free-standing outer/vent arch, similarly like here: https://community.fornobravo.com/for...827#post175827

So I decided that my outer arch bricks/legs will stand directly on hearth concrete, mainly because tiles/casi contact to hearth was not 100% flat and I was afraid of potential cracking. Will post pics soon.