Getting Started. Question on Vent dimension, and brick sizing

[McGooster]

Hi everybody — I am a first-time poster, long time lurker that is finally putting together everything to start building a 36” Pompeii Pizza Oven. After reading the Pompeii DIY ebook on Forno Bravo’s site as well as looking up others builds and I have come up with the attached schematic. There are a couple of areas that I do have questions about and was curious if anyone could help me or point me in the right direction.

Regarding dimensions: I have the opening set at 19” but am confused on the dimensions of the vent opening, how far the vent opening is from the oven opening, and lastly how far the oven opening is from the front opening? I have looked all over the ebook as well as other builds on this site but can’t find those dimensions for a 36” oven. Is any document or actual dimensions that someone can point me to figure out/calculate what those would be?

Brick size on the dome: I downloaded Deejayoh's dome spreadsheet excel document and had some questions to make sure I am reading this correctly. After I input all of my settings into the sheet the sheet came up with the following (attached screenshot). To make sure I am understanding this correctly, is this saying, for example, the Solider Row, that the interior face of the brick will be 3.57” while the outside will remain at its original size of 4.5”? Meaning there will be a taper on both sides to get these bricks down to 3.57” on the interior side?

Any other tips, tricks, guidance is welcomed as well. Thanks for all the help so far.

[JRPizza]

You might want to reconsider starting with a soldier course. When I got ready to start my build I found a couple of builds I thought were exceptional to sort of copy and noticed they did not use a soldier course. I think just laying bricks on their sides simplifies the build. Also I would not get too hung up on the spread sheet and would not do both a bevel and taper on my bricks. A bevel only will give you nice tight joints on the interior and save you lots of time. There is a thread about what would you do differently and several builders mention bevel only. I found the angles in the spread sheet to be a good reference but was able to eliminate internal gaps (vee) just by eyeballing/experimenting with the angle of cut.

[david s]

Mike I agree with you re soldier course. As the weakest part of the dome is the base, a long vertical joint there actually weakens the structure. The idea of a soldier course is to gain some extra height at the perimeter for high bread loaves and casserole dishes etc. It doesn’t matter for pizzas because they’re flat. The same height can be achieved laying two brick courses flat before following the radius curve. This allows staggered joints creating a stronger dome base.

[McGooster]

Thanks for the replies! I agree, I think maybe I will do away with the solider and just start with laying bricks flat. Appreciate the advice there!

Do you folks have any recommended dimensions on the vent opening? Also how wide that should be? I am struggling to understand what these dimensions need to be. Thanks

[UtahBeehiver]

On a 36" oven the recommended ID for the chimney is 6" so if you are vent depth needs to be at least this deep with the overall W X L at the top of the vent having at least the same square inches in area as the 6" chimney. A smooth transition from the start of the vent to the end of the vent chamber is best. If you are using a double wall SS vent pipe then there is an adapter plate The dimensions can be found in the chimney catalog, ie Selkirt or DuraVent.

[McGooster]

Thanks for the reply Russell. I was curious what your thoughts were if I was to have a ~8" x 4.5" vent opening? I have a drawing attached for reference. Would something like this work? Do I need to make this smaller? Thanks again fro the feedback. I will look into Selkirt and DuraVent for the chimney and dimension for the adaptor plate.

[UtahBeehiver]

I am going to ask you to explain why you think the opening should be this size relative to the chimney vent and type and mounting plate. It is a mental execise for not only you but other builders.

[McGooster]

Haha appreciate that. So after looking into the DuraVent Mounting plate for a 6" diameter chimney, I would have a 10"x10" mounting plate. Therefore the opening I have might be too large and I need to reduce the length form 8.3" down to 6" as that would be the diameter of the chimney..

[UtahBeehiver]

Lots of ways to skin this cat, you will need to transition from rectangular to squarish or round and you still need to maintain equal or more square inches of area cross section.



Do a search on anchor plate.

[McGooster]

Thanks Russell.

Appreciate the help there and the photos. I think I have it figured out. Just created a base that will support that 10"x10" anchor plate.

As I am gearing up for this build I did have some other questions that I was curious if you could help with.

1). After looking through a bunch of posts, I think I am going to go with the home-brew 3.1.1.1 mortar for my firebricks, but was curious what is the water ratio for that home brew mortar? Is it something specific or just an experiment until you get the right consistency?

2). On the first course of header firebricks (that go around and align next to the herringbone base bricks), do these need to be mortared? Or is it only on 1 course that I need to start with the mortar? Sorry if this is an elementary question, but just making sure.

3). When the dome is finished and ready for insulation, is there a preferred method within the community on insulation? I see a lot of Ceramic Blanket Insulation -> Vermiculite Concrete -> Waterproof Stucco but was curious if it was possible to do 3" Ceramic Blanket -> Waterproof Stucco?

Thanks for your help!

[UtahBeehiver]

1. It will vary depending on weather, brick, etc, start with a peanut butter consistency. After a while you get a feel for how much. I worked in small hand batches using 1.5 gallon plastic bucket.
2. No on the bottom, yes on the side first course only. Leave a gap around floor and dome (if floor inside dome), just place a ring of cardboard and just leave, keeps mortar from getting in gap and will burn out when you fire.
3. Depends, enclosed or not. But ceramic blanket if most efficient but most costly. 3" is a good sweet spot. Combination of ceramic blanket and vcrete is good depending on out coating and whether enclosed or not.