32" build in Calgary, AB - pompeii neapolitan

[IH123]

As you don’t actually have a soldier course (bricks standing vertically on their ends), the banding at the dome base is of little value, but if you are convinced it will improve your build, forge ahead. It also introduces the problem of anchoring the bands, particularly across the face of the of the oven entrance.

To clear up any confusion, the established terminology for bricklaying which has been discussed elsewhere on the forum is:

"on bond": bricks laid flat and subsequent chains staggered.
"soldiers": bricks laid on their ends, back to front (like soldiers on line up or drill marching).
" sailors": bricks laid on their ends side by side (like sailors lined up on deck)

Tip:
Also weighing with accurate digital scales, an individual brick both before and after being soaked in water then allowing it to dry and progressively weighing each day, is extremely instructive and accurate for the water content loss given the same weather conditions. eg, performing this test on a single brick until the scales show no further weight loss, gives one an indication of how long it takes in those weather conditions. Also if the brick feels cold then it is also still drying out.

the course at level 0 which will have banding, will be full circle 360 degrees including at oven entrance . Its approximately same level as hearth and I will adjust the bricks of that course#0 at entrance to be at hearth level if I find necessary , the banding will be around them too. the clip that holds a long strip of banding is on the outside so it does not effect gap between hearth and dome course#0. I rather think, the banding is very important, while the outward thrust is not strong, having a banding that is snug and adjusted after first firing will help keep dome in perfect position and prevent cracking a bit. I show below an illustration:

[david s]

As you don’t actually have a soldier course (bricks standing vertically on their ends), the banding at the dome base is of little value, but if you are convinced it will improve your build, forge ahead. It also introduces the problem of anchoring the bands, particularly across the face of the of the oven entrance.

To clear up any confusion, the established terminology for bricklaying which has been discussed elsewhere on the forum is:

"on bond": bricks laid flat and subsequent chains staggered.
"soldiers": bricks laid on their ends, back to front (like soldiers on line up or drill marching).
" sailors": bricks laid on their ends side by side (like sailors lined up on deck)

Tip:
Also weighing with accurate digital scales, an individual brick both before and after being soaked in water then allowing it to dry and progressively weighing each day, is extremely instructive and accurate for the water content loss given the same weather conditions. eg, performing this test on a single brick until the scales show no further weight loss, gives one an indication of how long it takes in those weather conditions. Also if the brick feels cold then it is also still drying out.

[IH123]

did not need any, though I have huge quantity of grog from wet saw cutting of bricks I could used that, shims and so on. I found the bricks I had are two, one is thickest and one that was squeezed in factory that its thinner a tiny and excess is on edge (about 1mm). so I hand select bricks from my 188 bricks (I had 175 and bought extra 13) then using my laser level I tested each brick and the one that have same thickness as the hearth batch on hearth I used it. I then cut and dry fit, I also rounded the edge of the dome bricks first (course #0), and most importantly I washed thoroughly all bricks from cutting debris and let them now set somewhere to dry (not on oven insulation). I also had the edges of each hearth brick grounded (smoothed out) so it wont tear anything on it. next week most of moisture would have gone as its weather forecast is 33C tomorrow. moreover, I redraw the oven centre line correctly for the final hearth. here is the picture of my cut hearth, laid directly on Thermobond 915 coat with zero levelling:

[david s]

A 50/50 mix of fine sand and powdered clay produces less movement than sand alone because the clay fills in the spaces between the the sand grains.

[IH123]

I today, marked the dome bricks outer circle to cut them rounded so that banding wont be exerting on edges rather balanced on entire brick outer surface/edge, likely will end up 3 straight cuts instead of circle cut (polygon part instead of circle part cut as its hard to get perfect circle on wet saw for 29 bricks). I also marked the hearth bricks for cuts, which will be about 1/8"-1/4" less than the dome diameter (I guess 1/4" is too much so will try to stick to 1/8"). I noticed the bricks are never same thickness so I will either use the play sand to level them or I could slowly grind and shave them as needed with rubbing brick to make them levelled. I feel shaving them with rubbing stone (grinding action) might be more stable for long term than having floating play sand. if I cant shave the bottom easily or if it takes too much then I will of course use the play sand, here is the picture:

[david s]

Ok, sorry, I didn’t see the drawing posted on post 121. Your first course of bricks (that you call soldiers) are not laid as soldiers, but laid flat conventionally and your hemisphere base is under the floor level. Sorry for my misinterpretation.
At the density you quoted for your bricks, you shouldn’t have too much trouble cutting them.

[IH123]

Ok, then ignore what I posted. I was looking at your plans as posted on #10 which shows a diameter of 32” and a radius of 16” and no soldier course (bricks standing on end)
Maybe I’m looking at the wrong plans.

I apologize for the confusion, the oven hearth is 32" diameter /16" radius however because I needed lower dome, the dome radius would be 16 1/8 to yield 14 1/8" height instead of 16". therefore the oven have two circles: hearth D=32", dome D=32 1/4". Except hearth, all my brick cuts are based on the dome radius of 16 1/8".

I hope that clarifies.

[david s]

not true for my sphere cap, true for hemisphere, see my diagram. my dome is a sphere cap not a 1/2 (hemisphere)- Neapolitan not Tuscan. its like I cut the bottom of the hemisphere to make it lower. therefore the radial faces can't be flat. the solider will fix the issue as its cut at the corresponding radial angle where the sphere cap sets on it like an arch set on a leg leg

Ok, then ignore what I posted. I was looking at your plans as posted on #10 which shows a diameter of 32” and a radius of 16” and no soldier course (bricks standing on end)
Maybe I’m looking at the wrong plans.

[IH123]

If that is your first course of dome bricks then you will not end up with a hemisphere. It probably won’t matter but a true hemisphere should have its base at the same level with the top of the floor. This results in the radius equal to the interior height.

not true for my sphere cap, true for hemisphere, see my diagram. my dome is a sphere cap not a 1/2 (hemisphere)- Neapolitan not Tuscan. its like I cut the bottom of the hemisphere to make it lower. therefore the radial faces can't be flat. the solider will fix the issue as its cut at the corresponding radial angle where the sphere cap sets on it like an arch set on a leg

[david s]

If that is your first course of dome bricks then you will not end up with a hemisphere. It probably won’t matter but a true hemisphere should have its base at the same level with the top of the floor. This results in the radius equal to the interior height.

[IH123]

one more showing inside out:

[IH123]

my bricks are 9"x4.5"x2.625" each weighs about 3.3kg, so that's about 1850kg/m3. I cut today the spring line course ,two wedges and top taper. course#0 in diagram, I dry fit but will have to cut the hearth bricks (later soon) before I could actually dry fit everything in final position and then assemble with mortar: I noticed my cuts are pretty tight which means the inner surface edges will touch each others however the gap will be more as it goes outside, up to about 1/4" between each bricks and another at the outside. I have huge quantity of grog leftover from wet saw water and shims that I can use to reduce refractory mortar (if needed), I have 100+lbs of Thermobond 915 theoretically enough for 180 bricks at 1/8". here are the pictures:

[david s]

The density of your bricks will be another thing to consider, particularly if you intend to do multiple cuts for each brick. They vary a lot, but medium duty are the most suitabl, especially if you intend on making multiple cuts for each bick. High duty are very dense, hard to cut and go through expensive blades quickly. This might be an important characteristic if you plan on multiple cuts per brick. Some builders have found them too hot. Low duty are very easy to cut, but at the other end of the scale are more prone to wear and can be not hot enough and lose heat too quickly. Medium duty as described by a supplier can vary from manufacturer to manufacturer. Reality dictates that you use what you can get.

FWIW my firebricks are 2290 kg/m3 or 2.29kg/L (you do the conversion if you work in imperial. They are not too bad to cut and produce a nice crispy base. Others may chime in with their brick densities, ease of cutting and cooking performance.

For what it’s worth my firebricks are2290 kg/m3 or 2.29 kg/L (you do the conversion if you work in Imperial). They are not too bad to cut and produce a nice crispy base. Others may chime in with their brick densities, ease of cutting and cooking performance.

[IH123]

I said earlier that I will keep the dome bricks floating on the insulation and so "(there will be parchment paper as a slip layer) but that can't level or added in layers as when it burns it could compress or dislocate."
I have changed my mind as I think when the paper burns it leaves gaps between the brick and the insulation top coat that gasses could leak out into dome render and exchange air leading to heat loss and also dome render insulation ceramic fibre mat fibre dust getting into cooking chamber from the little gaps. so I instead thinking of the following :


I will instead pad the dome bricks with very un-wet dry but little damp and VERY THIN refractory mortar such that its packed under the dome brick creating a tight seal, however it can't bond to the insulation coat properly that when dome expands if any cracks to happen they will occur on that not on insulation coat layer

but would the dampness from the head joint of the bricks fall down on that bed and wet it?might , but then I have to make it even more dry.


I today tried to smooth the insulation coat with rubbing brick however found about ~1/8" difference between right and left, so I wet it with damp sponge and I had set a level gaurd rails then I applied another 1/8" layer screeded and checked level with laser level it ends up perfect, picture below:






after 12 hours:

[UtahBeehiver]

If you go the route of precutting a wood pattern for you dome bricks, be aware the each course changes in bevel angle. I would suggest that you not cut a whole course of bricks at once, maybe 4-5 then evaulate how they fit and to see it adjustments need to be made. What looks good on paper does not always translate to real world construction. On a second note, as David mentioned, the brick hardness can effect wear on your diamond blades. I used super duty (surplus from an old steel mill, very high alumina content) and I went through a baker's dozen of diamond blades. I never have had any too hot issues with super duty bricks and once heated they hold the heat well.