Pdx 42" update

[JRPizza]

Look back at post #34. You have a couple of inches of fore/aft placement where the TDC brick will intersect the dome. People that need to shorten up their landing as much as possible due to design constraints can move the arch towards the center, but that takes up some cooking space and leaves very little protrusion to build the chimney up/over. I moved mine forward/outward as much as I thought I could and still have a good inner radius on my TDC, as I wanted to have plenty of arch sticking out for my vent area. If you have room, I'd say move it out (away from center of dome) but not so much as what you are showing in your sketch.

[Macrinehart]

Ok, hopefully this hits the mark. I adjusted back to the Point suggested by mongota, at the center line that's 3-13/16" inch inside the dome. I marked the IR line on the block, moves the arch back a little shy of 2 inches from the prior placement.

[Macrinehart]

Hi All - It's Saturday, what a day! Today I finished up the floor, decided to go with herringbone pattern and not regretting it. After spreading the sand/fire clay mix I decided to redo that work because the grain size was not fine enough. In order to get a better size I borrowed the fine siv from the kitchen, 2 mm square holes, and sifted all the pebbles out of my fire clay. Once that was done the notch trowel worked a lot better, and the floor went in easily as well.

I wrapped up the day by cutting all the perimeter bricks, and laying out the opening. The oven entrance is ever so slightly off center, but I think it's close enough that it will not be noticeable in the finished project. Overall I'm pretty satisfied with today's progress, but I think I will build the form for the opening before I finish.

[Hamilton]

Hey Mac, my name is Duane.
Couple of things!
Did you get any kind of security message when you logged in today? When I logged in through safari this morning I was given a warning that the Forno site certification has expired and may not be private. I ignored it and logged in anyway. Just a moment ago I tried it with google and got a similar message. You are the only other one that I can see that has posted today.
Next, while I am an no expert and hopefully somebody will weigh in here pretty soon.To me it looks like your entry bricks to the oven are to far back not allowing for the next brick to extend a little further in to the oven as you go up. I set the inner corner toward the front to the pencil line you have drawn for the outer diameter and trimmed the brick extending into the oven to match the inner diameter of the oven. As you go up there will be less to trim.
I found the forum after I has started my build and have been following your build/plans, I wish I had planned for a heat break, larger reveal around the oven entry and handled my IT differently, but we are going to get there. Closed my dome today, what a feeling!

[Macrinehart]

Hey Duane - Yes I did get the security warning today and I think there is a web server security issue someone will have to investigate.

Regarding the positioning of the bricks I believe I'm ok but I'm no expert either. My plan is simply to dry fit the opening arch first and use my IT, once it's setup, to verify the positioning. If any adjustments are required I will make them accordingly.

Thanks, and congrats on closing your Dome!

Cheers,

Mac

[Macrinehart]

And here's the form for the opening arch! This is cut 1/8" low so it can be propped on slats that I'll remove after the arch is done to drop the form and make it easier to pull out. Didn't have enough plywood to do the proper height so there is a gap on the bottom outside. Like the handle?

Cheers, Mac

[MarkJerling]

Hi Mac

Looking good. What you should check, before going too much further, is whether the top brick in the entry arch is able to meet the dome. What that means is that your door reveal position, in plan form, will be determined by the length of that top brick which needs to allow an angled cut for the dome brick to sit on. Because the dome curves inwards, your door reveal may well be closer to the centre of the oven, if that makes sense.

So before you go further, place that top door arch brick and then see where that brick "sits" in relation to your IT. That will tell you if you need to move the door arch in or out. My guess is it needs to go in, looking by your photos.

Yesterday, the site's security certificate appeared to have been expired, but that's now fixed, so we can again log in to an https:// site as opposed to an unsecured http:// site.

Kind regards,
Mark

[Macrinehart]

MarkJerling - Agree. My plan was to finish my IT, place it and then build the opening arch using 1/8" slats instead of mortar to dry-fit. Then I plan to use the IT to verify that the arch is positioned correctly before I move further into the project.

I am also considering whether to stick with the current arch height, which is a little under the ideal ratio, add another row if bricks on the bottom, which would be a little over the ideal ratio, or possibly pay a layer of cut bricks to raise the opening arch to the ideal hight. As it stands, I am a bit concerned that having the arch too low will make it harder to work the oven in the future.

According to pompeii_dome_calculator file my ideal opening arch height should be 14 1/2". My current dome height is 12 5/8". If I do an extra layer of brick without cutting the opening arch will be 15 1/4". Welcome any opinions on this topic.

[UtahBeehiver]

63 to 65% if the dome height is the rule of thumb for the internal arch height. It is not set in stone, I have seen arches below and above this ratio and they appear to work fine. This rule of thumb is derived from an old pioneer study from Canada on bread ovens called " Bread Ovens of Quebec" published in 1979.

[JRPizza]

Are you still building a 42"? I had thought the "ideal" ratio was 63%, which for a 21" high internal radius would be 13.23" - not sure where 14.5 is coming from. The FB plans call for a 12.5" opening with a 42" oven, so you are in that ballpark and probably lots of ovens built that way. Your 12 5/8 will probably be just fine.
Also, do a sanity check on any numbers you get from the calculator. I get some odd numbers from it, which is why I didn't use it.

[mongota]

According to pompeii_dome_calculator file my ideal opening arch height should be 14 1/2". My current dome height is 12 5/8". If I do an extra layer of brick without cutting the opening arch will be 15 1/4". Welcome any opinions on this topic.

I'd go with 12-5/8" versus either of the other two numbers.

[Macrinehart]

They said there was a "slight chance of snow", which is rare for Portland at any time of year. But this defies expectations!

[mongota]

"It's just a flesh wound..."

Welcome to the wacky world of WFO building! Mother Nature seems to throw a few punches at every build.

[Hamilton]

Dad gummit! Mac.

Hate to see that!
Hope the saw survives! I'm sure the oven components will dry out and be okay.

[Hamilton]

Hello, anybody out there?
Have you thawed out yet?