42" In South GA

[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”.

[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!

[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]

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.

[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.

[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]

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]

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]

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?

[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?

[JRPizza]

Yes my oven was build with tight joints in the inside and big wide ones on the OD that I filled with mortar. I don't think some minor lack of adhesion (if that is what the cracks/separation is) in the first course will hurt the oven, but if it is lack of adhesion you probably need to dial in your mortar consistency and brick moisture before you get to far along. If you go back and look at my build I think I redid some of the joints that were not stuck well. Discussion started around post 18.

[edonovan]

Thank you JRPizza. Agree on the brick moisture is playing a role, some of these brick have been in the rain and are saturated and not grabbing well. So I got a whole course done yesterday and started on the next. And who would have guessed...I have questions ...
1) Picture 1, does that look correct as that first arch brick and then I will just have to do a small wedge in that large gap next to it ?

2) Picture 2, 3, 5 This is rough draft of arch layout, I know I have large joints and still deciding if I want to taper, but I am struggling to figure out how far in or out the dome intersects. Does picture 3 look like I am on the right page as you want to figure out TDC first then work your way down? and It seems like it is intersecting it fairly far out and taking most of that full brick? I know I have read this what feels like 1000x from UtahBeehiver explaining it, but something is escaping me. ( UtahBeehiver, I hope you are enjoying the mountains of snow you are getting...I am jealous just watching all my weather reports )

3) Picture 4, exactly how far up do I begin needing to bevel? Is it really just when I start seeing a inverted V? and Is it the same direction bevel on both sides (bottom brick) or opposite (top brick), and any trick on "how much bevel" or is eye balled?

4) Last but surely not least...as I have said in previous post...I am slightly "out of round" maybe 42.5" at places and right now my IT is useless to me...one, if I were to use it I would have a huge lip of bringing that brick inward, two, If I place it in the IT correctly It almost tilts the brick backwards as having a joint line on the inside.. Is there a course that I should really start using it? I have again just been "eye-balling" my courses based on the previous picture and "cheater jig" and giving about a 1/4 + joint on the back and keeping that uniformed all while trying to creep my bricks in just a bit to get me back to 42"

You all have been great!! and I will say, once you get that first course laid and mortared, It feels good...and you can "actually" see a light at the end of this tunnel...not saying that tunnel doesn't grow at points and probably goes dark...but definitely feels good.

[JRPizza]

This is a good time to sit back and make sure you have everything straight in your mind.
If you look at the first attached pic you can see how the top of the arch bricks are tapered to match the slope of the dome bricks at the same level. If you follow that slowly changing top angle on the arch bricks down it becomes the angle on the side of the arch bricks facing away from the opening like I show in pic #2. Until I figured this out I was doing similar to what you have which I show in pic #3 (the layout I didn't use). You could go ahead and fill in your gap with a wedge but you will need to start angling the outboard side of the bricks to mate with adjacent bricks and the inboard edge to mimic the ID of the dome. If you can still recover I'd consider recutting the bottom arch and adjacent bricks. It also looks like your arch brick is angling in a little, at least in relation to the floor bricks. If they are at the proper angle you should readjust the arch angle. Lastly (for not) is a trick you probably saw where you lay your arch form flat and play with the look of your arch without having to mess with any shims or fight gravity.

[JRPizza]

For arch placement, you just need to make sure that your TDC brick will fall into the "shell" of your dome so you aren't out of round when the arch and dome intersect. I attached a few cad pictures so show what I mean. It is not an exact placement in that you have an inch or two to play with fore/aft (in/out). I chose a more forward placement so I would have more arch to build my vent over, but still have enough sticking back into the oven so I could have a good seat for the upper dome brick.
For your inverted vee I just started beveling when I could see a gap bigger than what I wanted to fill with mortar, which for me was early on as I wanted tight joints in the interior.
Lastly, I am not sure I understand your out of round situation. You only have one course so you might want to reset that and eliminate the problem. You need to use your IT starting at the second row or you will need to shim as the inner face of the dome bricks needs to be properly set along the radius of the ID.

[UtahBeehiver]

JR covered the placement of the bottom of the arch. Here is a pic on how each of the angles of the tapered inner arch brick are determined. PS, it is also dumping loads of snow right now, almost too much, avalanche danger is really high.