Building The Dixie Darling

[JRPizza]

My plan is to cut all the arch bricks to the left and right of TDC and then make up any difference with the center brick. I bought a few 9 x 4 1/2 x 3" brick so if it turns out I need a thicker brick for that top one, I'm set.

Once you get your dimensions, I recommend dry stacking the bricks around your form, and marking the approximate location on the form so mortar/joint creep does not make you have an odd sized key stone, unless that is the look you are going for.

[JRPizza]

Here is a copy of the spreadsheet. I had to zip it as the excel format is not one of the ones the forum is set up to accept, so if you ever have a file liyou can't upload you will need to zip it. That is what I did with my cad files too.
To use the spread sheet, you input into the cells with a green header and get the outputs under the red headers. For the wide part of the brick I used the nominal width of 2.5 inches (W1) and after you input your radius and joint thickness you will get the smaller dimension (W2). You can also vary the number of bricks, but I think an odd number looks best as you will have one brick right at TDC. Let me know if there is a problem or if you can't figure it out - lots of spreadsheets make sense to the creator but nobody else

Also, the FB plans recommend a height of 12.5 for a 42 inch oven, not the 13.5 you are showing. If you do target a 12.5 high opening, your 10 inch radius will fit perfectly on just a single brick, not the two full bricks you show above (your opening will actually be slightly bigger than 12.5 due to mortar joint thickness). This worked great for my 39" oven, as I had a radius of 9.75, so sitting on a full brick I had an opening of 12.25 (again, slightly bigger due to joint thickness)

[WarEagle90]

JR, I'm sure I will have plenty of questions going forward. It all looks pretty simple watching you guys do it, but when it comes time for me to start cutting and mortaring it doesn't look so simple anymore. My plan is to test fit as much as I can before the mortar starts flying. I will most definitely taper the arch bricks, if for no other reason just to prove to myself I am capable of doing it. I think I've got the dimension worked out or at least they work in the perfect world of CAD. I know that doesn't always transfer to the real world, but I think it will get me close. With that said, I would love to see the spreadsheet to see how close my dimensions match up to it. The drawing shown below is without an adjustment for the mortar joints and I will adjust the final dimension to something I can actually measure. I think the final numbers end up being around 2 1/8" at the top and 1 3/8" on the bottom. My plan is to cut all the arch bricks to the left and right of TDC and then make up any difference with the center brick. I bought a few 9 x 4 1/2 x 3" brick so if it turns out I need a thicker brick for that top one, I'm set.

[JRPizza]

I would not have tackled this project had I had not had the knowledge that the folks that came before me would be here when I had questions.

So true! I only figured out how to properly locate an arch after lot's of help from the forum, and I needed help through pretty much every step of the way! I lost track of the times I told my Wife "the next step is the hardest" The key is don't start mortaring till you have a pretty good feeling about what you are doing!
PS, if you are going to taper your arch bricks to maintain a constant mortar joint (as viewed from the front), ask for help if you get stuck. I have a spread sheet I made that might help with the dimensions.

[WarEagle90]

Thanks Russell and JR. You both confirmed my suspicion that the arch form is to thick. The way I have it positioned, the outside of the form is even with the back (outside) of the arch bricks. I built it before I had actually laid the oven out on the hearth. JR, I used your method of placing the location of the arch as the photo below shows. I played with the position of the TDC brick of the arch until I got something that looked good to me and that ended up being 14 inches from the center of the oven. Given that dimension the back of the 9" brick would be 23 inches from the center and that is where I set the arch form. So to fix my issue I need to shorten the depth of the arch form so that the inside will intersect the inner radius of the oven at the cut brick shown in the previous post and leave the back at 23 " so I have something to keep the bricks aligned to. Sound about right to you guys? Thanks for all your help. I would not have tackled this project had I had not had the knowledge that the folks that came before me would be here when I had questions.

Russell, thanks for the Tapered Arch PDF. I do plan to taper the bricks as noted in the article.

[JRPizza]

Dan, how wide/deep is your form? Mine was narrow enough that the fore and aft edges of my arch bricks could index against it to keep them inline. It looks like your bricks might not hit on front and back till you get a ways up the dome, at least judging by your picture #3. As you build the arch up the bricks will project further into the dome, so yes, the bottom of the brick should match the brick below it and the top should it a line created by the IT. The bricks will have a lower angle that I believe is somewhat tangent to the radius of the form.

[UtahBeehiver]

The placement of the inside of the arch form should intersect with the line you scribed with pencil mark from the IT. If you are doing a tapered inner arch (recommended) the attached is a pdf showing how the IT helps you lay the arch out. You start with the "top dead center of the arch" TDC and work down either side. Taper Arch Help.pdf

[WarEagle90]

4" of CF board and 12 x 12 x 3 tile are all set on the hearth. Inner arch form is set and ready to go. I am questioning myself on how I cut that first brick setting next to the arch. I simply used the IT to mark the cut line as you can see. Would the next brick up use the same line for the bottom and the IT across the top? That's what my mind is telling me, but I am just not sure.

[WarEagle90]

That’s probably not a bad idea. Wouldn’t be to difficult to just run down each edge with the grinder.

[UtahBeehiver]

One more thing, I remember a builder who chamfered all the edges of his floor bricks (4 x 9), very slightly, maybe 1/32 or less to minimize catching a peels. Kind of thought it was a lot of work for regular fire bricks at the time but with these large tiles it may be worth looking at.

[WarEagle90]

Thanks, Russell. I did not recall anyone sealing the seams but thought I would ask.

[UtahBeehiver]

Right or wrong, I did not seal any of my CaSi or FoamGlas seams. You are correct on needing to make multiple passes for the arch bricks. I did cuts from both sides then touch up middle or rough spots with a diamond cup wheel on an angle grinder.

[WarEagle90]

More progress. Got all the insulation and floor tile cut today. I built the wooden tile to replace the center tile during construction and attached the IT. I am using 2 layers of insulation (4" total) under the floor and was wondering if there is any need to seal the joints between the CF boards with a refractory caulk/sealant or something similar before placing the tiles on top? I have staggered the joints between the two layers so there is no direct path to the hearth except where two joints cross. Tomorrow I will mix up fire clay and sand paste to level the insulation and then repeat for the tiles. One other question, I am using a HF 10" wet saw to do all my cutting but it is not large enough to make the required 4.5" cuts on the inner arch brick, at least not in one pass. How have others accomplished this task?

[WarEagle90]

Joe, I am using the plywood template simply to get a feel for the dimensions of the oven and to help with its placement on the hearth. Will also use it for marking the insulation and tile for cutting. I want to use wood in place of the center tile during construction to attach the IT to and since I am using 3" thick tile I can make the wooden "tile" 1 1/2" thick which will lower the pivot point of the IT closer to the oven floor. I'll have to give some thought to the issue of low duty brick vs the tile. You bring up a good point.

[Gulf]

I can't help but ask. If you are going to use a wood tile for the anchor point for the IT, why are you using a plywood template? If it is for protecting the floor tile from mortar, cardboard or loose sand will do that.

Just a little something else to think about: It has more to do with folks cooking pizza and breads directly on the floor. Low duty firebrick are what is recommended by many for the floor brick. I can't really say for sure. I have low duty on my floor, but I mostly cook in pots and on pans.