42" In South GA

[edonovan]

Did a little sanding the afternoon to knock down the high spots. JRPizza when looking over your build I remember you having large joints in the back like I have going here. Should I be worried about these little cracks or separation?

[edonovan]

Mortar!! Feeling good!!
We will see what it looks like in the AM. It was chilly but humid here and as I made it around, some of my first joints were getting little hairline cracks in them, so I am not sure if it was setting to quickly or what. Based on my dome jig (I know it is raised on the cardboard and feet), just using for assistance...would the next course be flat also? Or start angling them up? Also based on said jig, most of my joints are about 1/2”, is that a problem being that it is on the backside?

[MarkJerling]

MarkJerling Thank you for your answers and insight! Yeah going 20” dome height, 12” x 19” door opening. I feel better now moving forward and actually starting to mortar.

Thank you. I look forward to seeing photos!

[edonovan]

MarkJerling Thank you for your answers and insight! Yeah going 20” dome height, 12” x 19” door opening. I feel better now moving forward and actually starting to mortar.

[MarkJerling]

You know when someone like me who is not used to planning (kind of a seat of the pants kinda guy) this stage is quite tedious...that being said I feel like I am almost ready to mortar my "first course" (I air quote those because It is floor level). Some questions that are absolutely racking me
1) I have these little weird spots in my "first course" that don't matchup well with vent landing. Do I cut a odd shaped brick to fit in there (pic 5) or leave as is (pic 1)? and do those get mortared to vent landing/entry?

2) My understanding is that the inner arch goes right over that "weird brick" spot (pic 2) and then my flared opening extends from there, correct?
I have a 19" opening that flares out to just about 23"...using pizza_bob inspiration
3) based on my slight out of round that I mentioned in the last post, once I start going up, should I just creep each course in a bit (creating a hair of a lip) until I get back to my 42"?
4) Placing inner arch?? I have read and read...are they most all full bricks? I know TDC is and then beveled to tie in. So is that the best way to determine where the inner arch sits, use IT to see where a 4.5 brick will lay on the TDC?

5) last one for this post ...the dome jig I made (pic 3) is that going to be my best asset for angling my courses? as I don't think the spreadsheet is much help to me...and If i use a string method to double check my It am I going from center to bottom edge or top edge of said brick course?

I am sorry for all the questions ...definitely new to a project that you are mortaring in place and mistakes are not easily fixed or corrected.

1) Yes, cut an odd shaped brick.
2) Yes, but, of course the oven is a dome so as you go up, the inner arch goes deeper. (Feel free to check out my oven drawings which includes a cross-section.)
3) It really does not matter whether you're 42" (and therefore 21" high with your dome or 42.5" or whatever. If you have any course that is less than perfect and you don't want to redo that course, then siply make minor corrections as you go up.
4)As you build up, you'll see where the inner arch extends 'inwards' to. The trick is to have every brick layer marry in nicely with an odd shaped brick where your arch joins your dome. Of course, make sure that your top of inner arch measurement is about 65% of dome height, so with a 42" round 21" high dome, your top of inner door arch should not be higher than 13.5".
5) I'll get back to you on that.

[edonovan]

You know when someone like me who is not used to planning (kind of a seat of the pants kinda guy) this stage is quite tedious...that being said I feel like I am almost ready to mortar my "first course" (I air quote those because It is floor level). Some questions that are absolutely racking me
1) I have these little weird spots in my "first course" that don't matchup well with vent landing. Do I cut a odd shaped brick to fit in there (pic 5) or leave as is (pic 1)? and do those get mortared to vent landing/entry?

2) My understanding is that the inner arch goes right over that "weird brick" spot (pic 2) and then my flared opening extends from there, correct?
I have a 19" opening that flares out to just about 23"...using pizza_bob inspiration
3) based on my slight out of round that I mentioned in the last post, once I start going up, should I just creep each course in a bit (creating a hair of a lip) until I get back to my 42"?
4) Placing inner arch?? I have read and read...are they most all full bricks? I know TDC is and then beveled to tie in. So is that the best way to determine where the inner arch sits, use IT to see where a 4.5 brick will lay on the TDC?

5) last one for this post ...the dome jig I made (pic 3) is that going to be my best asset for angling my courses? as I don't think the spreadsheet is much help to me...and If i use a string method to double check my It am I going from center to bottom edge or top edge of said brick course?

I am sorry for all the questions ...definitely new to a project that you are mortaring in place and mistakes are not easily fixed or corrected.

[edonovan]

JRPizza Thanks, my IT is adjustable and resembles plastered. Here is a rough picture of what my IT against a brick looks like. Upon double checking and triple checking, my floor is slightly out of round at some points maybe 42.5”. I figure once moving upwards I will be able to correct/“fix” my shape.

[JRPizza]

Your spread sheet screen shot is too small for me to read, but 12.5 would be the recommended opening height for a 42" oven, and 21" would be the height if you are making a hemispherical dome. I didn't use the spread sheet as I found it just complicated what I was trying to do. I was fortunate as I had my IT with both the pivot point and the center of rotation at the center of the oven and at floor level, so I just set the length at half of the diameter I wanted and went at it. I adjusted the bevel of my bricks by eye and was able to eliminate the inverted vee without having to try to dial in specific angles. I would have to see a brick in your IT to understand how it will place bricks in the dome. Usually the center of the brick is aligned with the center of your pivot. Below is a link where I have discussed different IT pivot locations.
https://community.fornobravo.com/for...349#post411349

[edonovan]

Alright...plan, plan and more planning...really hoping to start mortaring in the next week or so. Got IT set in the center and it is 1 3/8 above floor, cut a bunch of brick today and laid them around for a visual and put some numbers in spreadsheet calculator, and that is where my questions start coming up. running the first course as a stretcher..I put in 2 1/8 (second course and thickness of brick) as the measurement "above floor/first course" Should I stay with opening height of 12 to 12.5...calculator states 14?? additionally, dome height? I read that 20" is my ideal, calc is saying 22.4, stay with 20"?
With all that being said is this spreadsheet going to help much if those measurements are "off" and I am not planning on using a "jig"? so far I have had fairly good luck with diamond blade on chop saw and grinder (other than the mess, I live in the woods). Still have some cutting of perlite board around my vent floor, which I did end up reading is water repellent (hydrophobic)...that is a plus!

[edonovan]

Ha, Russell.. Knuckle dragger...lol, yep!! I ride all over, we just did Big Sky in Montana. I really love proximity of everything in Utah, have done Brighton, SnowBird, Park City.
I took plastered direction of simple (non weld) IT. So yes mine is adjustable.
thanks for the insight on leaving at least an inch or so to build up for mortar in the front of of the insulation, I wasn't sure how well anything would adhere to it.
Also, I think I am going to call Johns Manville and ask if the Perlite is somewhat water repelling. I know you commented earlier as not seeing it when comparing Perlite vs. Insblock, but I left a couple scrap pieces out in the rain and today they sure didn’t seem water logged, maybe a bit more “chalky”.

[UtahBeehiver]

So you are a knuckle dragger huh, where did you normally ride? Back to business. The pivot point off the floor elevation will increase the dome radius incrementally with the dome apex being the largest increase. I cannot see it your IT is adjustable or not. You can correct each course to the correct radius with an adjustable IT. This is important if you do a tapered inner arch. Do not move the inner arch in to adjust for outer tiles, this affects how the dome ties into the inner arch. Adjust the length of the vent chamber bricks if you need tile space. You will probably need a fairly thick mortar bed against the insulation to attach the thinset the tiles to (ie 1" or so) because the mortar bed will not generally bond to the insulation very well.

[edonovan]

This insulation sure is brittle! Got another box of perlite for my 4” and did a rough layout with my floor, need to push it back a bit. Wondering if I should set back my entrance about 3/8 or more to account for any decorative tile to finish off my base. A tile mortar should adhere to the perlite right? Also considering cutting my entry a bit after where my inner arch will sit, as I have read people just having running bricks and don’t have to have a herringbone. Hope to be going upwards soon, more photos to follow.

[edonovan]

Christmas...check....New years....check...snowboard trip...check!
Now that all of that is behind me time to get moving on this thing! Got my weep holes drilled today and first layer of Perlite board cut. Need to grab another box to give me the 4” of insulation I want to do. Upon measuring that will give me a cooking floor height at 41” which is almost perfect for limiting bending down for fire/pizza check. Also, had my IT built with a caster and read more on the pitfalls of the caster. Went on a fork bolt search and found this guy...question, is 1 3/4” off the floor too much for my pivot point? Will I have more issues with this then the caster or just adjust my IT according to the spreadsheet?
thanks in advance everyone

[mongota]

edonovan [QUOTE=edonovan;n433628][USER="19129"The place I am getting this from has either 2" thick or 2 1/2". Is 1 layer of 2.5" enough to retain the heat and have a couple days of cooking or should I go with 2 x 2" thick? [/QUOTE]


It's tough, because our individual needs in oven performance and the environment they preform in can be so variable.

I can tell you that the only day I regretted going with two 2" layers for a total thickness of 4" of insulation board under the floor was the day I bought the insulation. Cha-ching!

In the several hundred fires and the multi-day cooks I've done since? Not one day of regret.

[edonovan]

UtahBeehiver thanks for the voice of reason....with that being said, I am purchasing that this week and remember reading someones words on here about "not wanting to end up with a really expensive fireplace". The place I am getting this from has either 2" thick or 2 1/2". Is 1 layer of 2.5" enough to retain the heat and have a couple days of cooking or should I go with 2 x 2" thick?