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[karl]

Hello to the forum members,

You may have observed (from other threads) that I have started my pizza oven project, but have not yet commenced on the oven dome yet. I have understood that a good approach will be to start with the oven opening arch and vent and then continue with the oven rounds locking them against the opening towers.
The locking is very important since, as the brick rings start to incline inwards, it prevents the inward collapse.
However, as I "climb" up the opening towers the contact area between the incoming and outgoing ring bricks seem to move from the towers east/west sides to their north/south sides (inward and outward sides). I.e. that the weight of the incoming/outgoing bricks are gradually transferred from the underlaying ring to the opening arch. It seems to me that the locking of the rings becomes more and more "suspect" up the towers since the ring do not lock against itself (is not complete) and meet the arch at a very "open" angle?

I have seen some pictures from ovens where the rounds bricks meeting the opening arch near the top of it seems to rely completely on the vertical fusion(mortar) between the brick itself and the arch both in its vertical (weight) and horisontal (locking) directions.

Can somebody of the more experienced builders give me some guidance and considerations about this "problem(?)" as it makes me uncertain on how to approach it on my own construction (soon to commence).

regards from Karl

[dvonk]

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I'm not an experienced builder in any senses, but I've found that the first few chains (up to the arch/dome lock level) of the dome are pretty stable by itself, I had no chance to worry that it will collapse.
But at the same time it was easier for me to cut arch and dome transition's bricks since I was able to play with each half-brick just because it was not mounted in the arch.
But as it was told here many times, there is no The Only One Proper Method.
Most of us developed home-brewed unique way of building the dome (based on the common ideas and technics)

[nissanneill]

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Karl,
I totally agree with your build plans from building your void anf both arches first. This gives the remanider of your dome build, something structually significant to bond and support with.
I build mine the same way and once the dome (oven entry) arch was set, I got my 9" angle grinder with a diamond blade (again from ebay for I think $14 + postage) and cut almost a 45˚ bevel on the inside tops of the arch bricks. This then became the 'NON VERTICAL' base for my transition bricks to sit and bond to.
The rest of the bricks were cut to maintain the strong stretcher bond necessary for a good oven build.

Neill

[dmun]

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Back when I was trying to get that refractory brick guy to make pre-fab arches I made up this sketch, which shows a simple way to build the entry:



As you can see, each side of the entry forms a "T" shape, with the short leg of the "T" the ledge that the oven door sits against, and the long arm of the "T" a short wall that the oven bricks lean against.

Even if you have to make up your own arches out of firebrick, I think it's still a good plan.

[karl]

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Neill,

Your method seems sound, but challenging. And I am a bit afraid of weakening the top of my arch by having to cut too deep into the upper bricks. I have decided to pull the opening arch slightly out and leave room for a "platform" (supported by irons) behind it which will support the first round which makes it over the opening. The platform will be level with the highest lower edge of the arch (not to be visible). I will also move the top 2 bricks on each side post inward (staggered) to try to follow the dome curvature better and establish the iron supported platform such that the whole round of bricks get supported over the opening.

regards from Karl

[nissanneill]

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You won't have to cut more that a 2" ledge for your dome course bricks to mortar onto whick will in fact make your dome and your arch stronger as it is adding a third dimension to the structure.
By pulling your arch foreward and supporting the dome bricks on a metal support, you are producing a weak vertical joint which could very easily crack and create further problems. I would always try to interlink all of my bricks wherever possible to produce the strongest structure.
You also need to consider the thermal expansion difference between your bricks and the steel supports that you intend to use.

Neill

[karl]

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By pulling your arch foreward and supporting the dome bricks on a metal support, you are producing a weak vertical joint which could very easily crack and create further problems.

Neill,

I do not really understand this statement. All the rounds lower than the support will be anchored firmly to the side post while the first round that make it over the "top" will continue across it and be a full round. What weak vertical joint are you refering to?

regards from Karl.

[nissanneill]

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Hi Karl,
the comment made that you don't understand comes from my interpretation of your explanation of what you plan on doing. I may have it wrong when reading it several times but I thought that you were going to pull your oven arch foreward and put in behind it a steel support that would hold your dome courses. This steel support (as I understood it) would hold and support the bricks but that still would not bond or lock into the arch but would be cemented up to it in a vertical mortar joint.
I have tried to find the perfect picture of the 45˚ bevelled arch brick photo here in this forum but as you are aware, there is just too much detail and information, especially for me as I can't remember where all the 'precious bits of information' are hiding. I thought that I kept the picture as I plan on using it in my next oven build . I have 2 pending at the present.
I will try to draw some plans/pictures to explain it but I am off to my grand daughter's first birthday today. If I get home early enough, or if it is cold tomorrow, I will sit down and draw the plan of action that I think you are doing and the way I would do it.

Regards.

Neill

[karl]

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Neill,

If you can find the time I surely appreciate it. I guess my own plan would simplest be explained as making a rectangular opening and disguise it behind an arch.

regards from Karl

[nissanneill]

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Hi Karl.
I got home at around 10pm last night and started the drawing.
Here is what I was trying to put into words. I would always build my arches and chinmey void so as to have something solid to tie/key my dome rows into.
With a steel support behind your oven arch, it will support the dome bricks but you end up with a vertical cemented join which when we read of the experiences of some of the oven builders, get cracks.
I personally would becel the inside of my oven arch bricks and then cut the dome bricks to fit/lock forming a much more substantial (leak/crack resistant) join.

Neill

[karl]

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Thanks Neill,
I see what you mean. I thought the 45 angle cut in the inner arch stones had to follow the curvature of the brick rounds and hence had to cut very deep into the middle bricks. A 45 egually deep cut in each looks sound an I guess the discontinuity in the circular shape of the brick rounds over the opening can be gradually compensated in the next rounds?
Nice drwaings by the way!

regards from Karl