36" WF Pompeii Oven in Maryland

[bentedesco]

The RedGard has 4" of board insulation between it and the floor brick. Before I added the stucco shell over my dome, I had a couple fires and slid a thermocouple underneath the floor, between the 4" of board insulation and the hearth slab. The hearth slab has the RedGard painted on it. I had readings between 92 and 95 degrees as I moved around the circumference of the floor.

A cement-based waterproofing material like Thoroseal is always an option. I used that over the top of my stucco.

Very impressive results! What about painting the sides of the Fb Board? I'm a little worried about water seeping in from the sides... maybe I could just cover the sides and corners with foil?

[mongota]

Your explanation of the heat break w/the ceramic fiber rope is perfect, do you remember the diameter rope that you used?

The idea of different patterns of brick for the entry arch floor intrigues me, however, I'm confused how this helps as a heat break? I think I'll also go with the inverted 'V' and stuff it full of Ceramic cord.

I know I'm probably overthinking, but as an engineer, it's hard to turn that part of my brain off.

I used 1/2" ceramic fiber rope.

Regarding the pattern break from herringbone to running bond, it's simply that it's NOT a continuous run of brick from the hot to the not hot part of the floor, which is better than continuous brick. The door, coupled without there being a continuous piece of brick running under the door from oven to entry, the break in the pattern at the door does help reduce conduction from the oven floor brick out into the entry arch floor brick. I shot some temps a while ago, but I don't recall the temperature differential, it's not written in my notes.

The lack of a true heat break at that pattern change is not something I'm overly concerned with. The break in pattern is good. Undercutting it and adding insulation would be even better. But your oven will still cook without it.

I started a fire about 45 minutes ago. When the oven gets saturated, I'll try to take temps.

I get the "I'm an engineer thing". lol. BS in Chem Engineering, MS in Applied Math and Physics. Sometimes the thought process simplifies things, sometimes it doesn't. There's always ONE more improvement to be made. Often times the best thing is to ditch those thoughts and go with common sense. lol

[bentedesco]

I get the "I'm an engineer thing". lol. BS in Chem Engineering, MS in Applied Math and Physics. Sometimes the thought process simplifies things, sometimes it doesn't. There's always ONE more improvement to be made. Often times the best thing is to ditch those thoughts and go with common sense. lol

Ha! Sounds like you've been talking with my wife, I'm a continual tuner... often to my own detriment. I enjoy the process of perfecting a design or as my wife will say "breaking things that don't need to be fixed" Oh well, it is fun to think about how to best optimize the oven... but I agree, I think I'll just use Ceramic Cord + a few tubes of refractory Sealant up top and then I'll undercut the bottom bricks and possibly stuff it with some remnants of my blanket. Thanks for all your advice!

[mongota]

Very impressive results! What about painting the sides of the Fb Board? I'm a little worried about water seeping in from the sides... maybe I could just cover the sides and corners with foil?

I painted the side of my insulation. The RedGard was painted on the hearth slab, a few inches wider than the footprint of the board insulation. The insulation placed on top of the RedGard. More RG was painted on the edges of the board insulation and lapped down on the the hearth slab RG to seal the corner.

Ceramic fiber rope. 1/2" diameter. RTV hi-temp silicone was used to adhere the rope to the brick.

You'll have a cap over your chimney, so water down the chimney flue should be a rare thing.

I'm not seeing the photos that I tried to load last night, I show a "photo does not display" icon. These are the same ones:

[bentedesco]

I just scored 75, 8" x 8" ceramic tiles for free off a facebook yardsale group . (I'm liking this idea david s had here: https://community.fornobravo.com/for...444#post407444)

I think I'm going to lay these out and then use my angle grinder to score the concrete surface to create channels for the water to lead to the weep holes. Hopefully, I can lay my CaSi Board down on top of this tomorrow and start on my floor!

[bentedesco]

Today was a good day! While it doesn't look like much progress, I was able to clean up some of the mortar on the outside of the base and get my coordinates set for the oven. I also scored around my weep holes to hopefully channel water towards the drains. I think I have figured out my final alignment for the tiles before I cut them tomorrow (so I don't cover the weep holes). And then I'll get started on laying the CaSi board tomorrow.

Do you think I've allowed enough (or too much?) space between tiles?

[Gulf]

If it were me, (and I wanted gaps) I would close the gaps up to 1/8th or 3/32 inch. The spacers are readily available. I wouldn't worry so much where the drain holes are. When a tile crosses one, you can just cut that particular tile to tie the hole in to the grid.

[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.

[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]

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]

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)

[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]

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]

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

[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.