Scratch build thread - 36-inch inner diameter dome oven

[MrBravo]

Have to ask. The purpose of the tile mesh?

[mnagy]

Putting these mesh tiles upside down on the hearth causes there to be channels between the tiles that allow water to seep through and find the drain holes. Bunch of the pros on here were suggesting it, so I just copied them.

[UtahBeehiver]

I did not mortar the bottoms of the first row. My first row sits on the CaSi board with the floor cut to fit inside. Nothing wrong with the first row sitting on the brick floor either. That said, I have seen builders mortar the "bottoms" and not mortar the "bottoms" of the first row. My preference is not, this allows that floor to move independently of the dome. I can't tell how much offset you have on the inner arch the vent chamber, but a bare min of a 1/2" (1" better) is need so the door can seal the oven.

Your explanation of the tiles if spot on.

[mnagy]

Thanks! I’m going with a 1/2” lip around the door. I realize that’s cutting it close.

I’ll just mortar the first row dome bricks to each other rather than to the floor. My dome bricks will be sitting on top of the dome floor bricks (which themselves are not mortared down… They are just sitting on the vermicrete with a bit of clay/sand as a leveler).

[mnagy]

Here is a video of me pouring the concrete counter top alongside the brick floor (with ceramic blanket in between). Feel free to delete this post if videos like this aren’t allowed. I just can’t upload something this large. https://www.tiktok.com/t/ZT8N7fn1a/

I also have it on YouTube if that’s better. Is there any other way to upload videos here?

[UtahBeehiver]

Personal vids are fine, just commercial promotion, sales, hyperlinks, etc are not.

Wow, that is some wind/rain storm.

[mnagy]

Thanks. Yea, these are personal. I dont have any affiliate stuff, and definitely don’t have enough followers for making any $

[UtahBeehiver]

I look at your IT and there is a key design issue you need to be aware of before to go too far on the dome. The IT from the pivot point at the center of the floor along the length of the IT to the dome end needs to intersect the middle of the dome brick or the brick face will not be perpendicular to the center of the floor. This error is cumulative and you move up and the dome brick will start to step. Now is the time to adjust the IT. Also, the IT is not adjustable in length. Adjustable length is really helpful since there are so many variables that can affect the dome diameter. I have attached an IT diagram from another member showing how the line from the pivot to the brick should be.

[mnagy]

Thank you!! So the radius tool needs line up with the middle of the brick, rather than the top (which is the case currently). That makes sense, and you definitely saved me some major headaches.

I’ll see if I can make a simple adjustment to resolve this and will share a few pictures.

I suppose I could use some kind of turnbuckle to be able to make small length adjustments if you think that would be helpful.

Thanks again!

[UtahBeehiver]

Correct on the brick end but also important that the pivot point (ideally at floor elevation) along the IT "rod" intersects the center of the dome brick face.

[mnagy]

I rigged this thing up as a new end for my indispensable tool. Beehiver pointed out that my previous design had the radius aligned with the top of the bricks, rather than the center. This would have caused the position of the bottom edge to shift outward as the angle increases.

This new attachment will align the radius tool with the center of the brick.

will hopefully start laying dome bricks this weekend!

[mnagy]

Here is my new IT. The radius lines up with the center of the brick now.

The point of rotation is in the center of the dome, but as you pointed out it’s still about 1” away from the hinge point.

This means that as it is today, this IT will make a dome that is 1” taller at center than it should be.

The adjustment I would need to make to correct this without making a new tool would be to reduce the length of the tool by a small amount between 0” (at the base) and 1” (at the apex). Increasing the shortening adjustment as the angle increases. I think the reduction amount would be calculated as 1” x the tangent of the angle.

I’ll link a bit more about how I might fix this IT to line up more perfectly, but I’m tempted to accept this error and move on.

[UtahBeehiver]

1" height increase in dome height is not a deal killer and will not adversely affect the oven. You corrected the key error on the IT (center of pivot to center of brick alignment).

[mnagy]

Question for the pros:

I was thinking about making a 1/4” air gap between the inner arch and the outer arch. I was going to use high heat caulking around the outside of this gap as a smoke seal.

bit now I’m second guessing myself because I’m worried about the strength of the outer arch (which will be supporting the chimney). If I mortar the outer arch directly to the inner arch it will have a bunch more strength.

then again, if something bangs into the chimney and cracks something, I’d much rather the damage be isolated to the outer arch and not the inner arch and dome as well.

so the question is. What do I do? Air gap? Or no?

[UtahBeehiver]

What type of chimney? Brick, Double wall SS, Clay? Gulf installed a huge brick chimney and used a "L" shape arch thermal break. I tapered most of my arch brick away from the dome so just a bare min was touching and I used double wall SS. IMHO insulation priorities should be 1. Floor and Dome, 2. Door, 3. Floor and Arch thermal break.