36" WF Pompeii Oven in Maryland

[UtahBeehiver]

I take it you are taking about the entry arch not the dome.because I can see from the pics the dome courses are using the IT alignment. The arch with vertical walls will be what is called an Axed Arch. There was a recent post where the program for General Tools "angleizer" was posted (it is no longer available from General Tools directly). It will calculate the Axed Arch based on brick size, radius, width, height. Remember the opening arch height needs to be around 63-65% of the dome height. I've used this program several times and it is spot on.

I found the link,

https://web.archive.org/web/20160201...Angel-Izer.zip

[bentedesco]

Or move the center of the radius up off the floor, mine is made that way with the center up 4.5". I like the oval idea or a parabola. Or use a larger radius with the centerpoint below the floor and have a corner where the top meets the floor just like the opening arches are normally done. There is nothing magic about a perfect dome other than you get to make all the angles exactly the same which make construction a little easier.

Ah, brilliant! I knew there had to be a simple fix!

[mk e]

Or move the center of the radius up off the floor, mine is made that way with the center up 4.5". I like the oval idea or a parabola. Or use a larger radius with the centerpoint below the floor and have a corner where the top meets the floor just like the opening arches are normally done. There is nothing magic about a perfect dome other than you get to make all the angles exactly the same which make construction a little easier.

[rwiegand]

Or make the dome slightly oval rather than a perfect hemisphere by shortening the radius by about 1/8" - 1/4" per course until you get back down to your desired height. Also, if your floor is inside the dome (the preferred conformation, I believe) you will only have two bricks above the floor rather than three.

That's the way I built mine, but I also think it makes essentially no difference in use having the short vertical section around the perimeter. Building another oven I wouldn't bother. This was for a 42" oven, the difference might be more apparent in a smaller oven.

[bentedesco]

Lastly, I abandoned my design of stacking 3 courses of bricks straight up before starting to arc the dome as it had an inherent fatal design flaw. While I like the look, I realized that I would run into an issue with the radius still being 18" ~8" off the floor. Using the Pythagorean theorem, if I need an 18" 3-dimensional dome hypotenuse (c), & I have an 8" height (a), my horizontal radius(b) would be ~16.1". If I followed this plan, I would then need to significantly shift the bricks inward with about a 2" overhang to maintain an 18" dome radius. This is definitely the wrong way to go.

(I've attached an illustration of what it would have to look like from a side view)

The only way to avoid this would be to shrink the diameter of the pizza oven floor so I would have an 18" hypotenuse at the top of the three courses of straight stacked 8" bricks) This would then leave me with a ~16.1" radius on the floor of the oven instead of 18" (effectively reducing my oven's surface area from ~1000 in^2 to 800 in^2=) a 20% reduction in cooking surface is too much in my mind.

[bentedesco]

After being out of town for a while, I am back from my hiatus with a status report. Over the past several weeks, I cut my base and began to lay my first 2 courses.

I made a mistake at the dome entrance and needed to remove the "bookends" of the first course as the entryway brick was too thin. I have since rebuilt the bricks at the base of the inner arch to be squared off as shown in the pictures. All in all, the courses are going a lot faster than I thought they would. I've started to get into a rhythm where I will first lay all the bricks at the correct vertical angle (buttering on the bottom) and then I will go back around a second time while the bottom is still green and fill in the gaps in the side joints. Also, I've been very careful to re-wet the bricks with a wet brush when I'm doing this second mortar application.

Also, I found this little tool on amazon to be a godsend to check the vertical angles of each brick when I'm laying my courses:

https://smile.amazon.com/gp/product/B00T6YZ0K6/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

[bentedesco]

You keep mentioning soldiers, are you intending to do full soldier or half soldiers? Be aware the full soldiers may require some buttressing due to the outward pressure from the dome where the dome and the top of the soldiers meet. FYI, since you starting to get ready to lay bricks.

Oh! I was originally thinking Full soldiers, however, I don't think I have much room to spare for buttressing.

I'm glad you mentioned this tonight as I can change my design. I was still hoping to get some vertical height in my oven before starting the dome's slope.

I can think of a few ideas, if anyone has suggestions, I've very open to them!

Idea 1: I could do the first course of half bricks on their side, and then lay 2 additional courses of 1/2 bricks vertically (without any slope)
Idea 2: I could lay first 3 courses of 1/2 brick flat with 0 angle before starting to dome my oven.

Would either of these designs give enough structural support?

[UtahBeehiver]

You keep mentioning soldiers, are you intending to do full soldier or half soldiers? Be aware the full soldiers may require some buttressing due to the outward pressure from the dome where the dome and the top of the soldiers meet. FYI, since you starting to get ready to lay bricks.

[bentedesco]

Another very productive evening!

1. Picked up 6' of 8" chimney stack from a seller on Facebook for $60
2. Fixed my IT to correctly offset the center of the brick & made "windows" in the base to check to ensure it was centered
3. Laid & cut 2 layers of CaSi board (4" thick)
4. Sealed my CaSi Board with some high temp silicon around the seams (not sure if this will help any)
5. Since I was on a roll, I decided to spread some sand and lay my oven floor!

Tomorrow, I'm going to cut around my 36" ring for the floor so I can start laying the soldiers outside the floor (directly on the CaSi board).

Hopefully this weekend I can lay 2-3 more levels of my dome

[bentedesco]

Finally got my Ceramic Fiber boards on today!!! And... while I was taking the boards out of the box (I bought them off ebay) I saw a sticker that said "McGills Warehouse" Of course I googled them and found they have pretty decent prices on High Temp items- I'll let you all know once I get the oven fired up in a few weeks if these boards perform. Given the price I think I'm going to pickup a few of their blankets as well to insulate my dome.

EDIT: OWCH!!! Shipping is ridiculous

[bentedesco]

Quick update for today:

1. Unclogged weep holes using a 1/2" metal bar (most of the holes had 1" concrete plugs towards the bottom)
2. Bought my first 100 Firebricks for the floor and soldiers!
3. fixed my IT per UtahBeehiver 's suggestion
   1. EDIT: I just realize that I did the opposite and only further exacerbated the problem. Instead of having the brick sit deeper in "lip", this actually made the brick sit further out... tomorrow I'll "re-fix" my IT
4. Tightened up the ceramic tile and made necessary cuts for weep holes

Tomorrow, I'm going to measure and cut my CaSi Board (23" radius, 18" for interior floor + 5" for soldiers & buffer). I just did the calculations and I should have enough CaSi board to do 4" underneath the dome!

[bentedesco]

Let me try and explain a different way. By the latest pic. The shaft is offset from the center point so it appears that the top of the shaft comes closest to projecting down to the center point at the floor plus thickness of the ply. So if you follow the top part of the shafts to the other end the bottom the center is not where the center of brick is, IE brick 2.5" thick, center line from floor should be 1.25" from the TOP of brick. Also you have length adj. Capability on the IT

I *think* I understand what you are saying now, the long shaft needs to be inline with the middle of the brick. In order to fix this, I will need to shim the metal brace on my IT (as illustrated in the image below with the orange pieces)

(REF to this post by deejayoh : https://community.fornobravo.com/for...747#post225747)

[UtahBeehiver]

Let me try and explain a different way. By the latest pic. The shaft is offset from the center point so it appears that the top of the shaft comes closest to projecting down to the center point at the floor plus thickness of the ply. So if you follow the top part of the shafts to the other end the bottom the center is not where the center of brick is, IE brick 2.5" thick, center line from floor should be 1.25" from the TOP of brick. Also you have length adj. Capability on the IT

[bentedesco]

I can't tell from the pic of your IT but it is really important that the center line of the shafts on the IT intersect the center point of thickness of the brick. This makes sure the tilt of the dome brick is perpendicular to the center of the dome. If the IT is not set up this way the error is cumulative and shows up the higher you go. Also be aware that a pivot point of the IT above the floor will affect dome radius as you move up and will affect tying into a tapered arch. Since the IT is not adjustable you will not be able to adjust to these changes.

Thanks UtahBeehiver , Here are a few more pictures of my IT, If I'm understanding you, I think your concern was that my "shelf" wasn't centered on the shaft, I think that must've been the angle of the other photos. Please let me know if I'm missing something here

[UtahBeehiver]

I can't tell from the pic of your IT but it is really important that the center line of the shafts on the IT intersect the center point of thickness of the brick. This makes sure the tilt of the dome brick is perpendicular to the center of the dome. If the IT is not set up this way the error is cumulative and shows up the higher you go. Also be aware that a pivot point of the IT above the floor will affect dome radius as you move up and will affect tying into a tapered arch. Since the IT is not adjustable you will not be able to adjust to these changes.