Frank's Build

[fhausback]

So, I found some peels and brushes in a lot at a local auction. I obviously don’t need 24 peels and 12 brushes. if you have a need, and your local to The Kansas City area, let me know and we’ll make a deal.

[GreenViews]

Nice job laying out ahead of time. I did a lower dome and didn't find it hard at all other than figuring out how to properly create an modify my IT as you need a variable length and angle for each course. Several ways to do that, but I used a wood template to set the IT for each course. While you have your layout, just be sure you have turned whatever your dome pattern is forward against the inner arch and ensure your inner arch bricks extend fully into the oven space (for cutting off) to avoid the mistake I made: I cut my inner arch bricks too short and made a little dome void above my inner arch, which is now a "unique characteristic" of my build. Regarding flue area, after reading from other builds and flue design papers, etc I decided to make my entrance slightly longer than I was thinking, but not much for access. I was planning on coming down from my doorway just a tad, but my final design now just has a a very wide and large flue area, which I have yet to build, so I can't give any real world feedback myself. Look forward to watching your build progress further! Keep up the good work! Great auction find!

[fhausback]

I think i have my geometry finalized, and would like you all to share any corrections/recommendations. I'll make a wood template of the arch and use it to set the IT for each row. I think the below "looks" like a good compromise between a low and high dome. Once I draw the arch full size on plywood I may add a 2nd row of vertical bricks and adjust the curve.

50" diameter
20" high dome
13" inner arch = 65% ratio
20" wide opening on inner arch
17.5" radius on the arch, i'll figure out the brick count and taper once I have my arch centering template built.

[UtahBeehiver]

Good start, not too many low domes being done so will be interesting to follow. Couple minor comments, FoamGlas is an option because it is hydrophobic, but by your drawing the thickness you show will not work because of the brittleness of the material. You will be better off with junky/surplus tiles to raise the CaSi off the hearth. Make sure you install weep holes in the hearth. Second, just confirming you are using ceramic blanket on the dome (you call it a batt) and not fiberglass or rockwool insulation. FYI, the 65% rule is more geared towards high domes. There is a table in the FB eplans for low dome entrance dimensions but not for a 50" but will give you scale that you might be able to interpolate.

[fhausback]

thanks for the comments. My scale is off on the foamglass, i did source 2" thick boards. It seems to be pretty strong at this thickness atleast.

Yes, what i call Batt is ceramic fiber blanket. I will be doing up to 4" of that, if my box of 1" batt stretches that far.

Its been awhile since i've read the original PDF, i'll check that table out.

[fhausback]

I finally found some reasonable priced J type thermocouples, with a short probe, and they appear to work great. Since I have no idea on the long term durability, I want to make them easily replaceable.

i picked up some 3/8” stainless tube that is normally used as fuel line. I’ll use this as a conduit and insert one end in bricks throughout the oven and in the insulation. I checked and I can push the thermocouple through 180 degrees, so I shouldn’t have a problem down the road. A fish tape may be needed in the future if something corrodes or blocks up the pipe.

the stainless will terminate under the main slab, and I’ll run the wires from there to the pyrometer in a TBD enclosure.

https://www.amazon.com/gp/aw/d/B07M6...age&th=1&a mp;psc=1

[fhausback]

Foamglass is down over tile. That stuff cuts like butter with a hand saw, way better to work with compared to calsil.

I have 4+ pieces of Foamglass left if anybody in Kansas City is getting started. In the end, I bet I’ll be posting a weird list of leftover supplies on Craigslist.

[fhausback]

My first layer of calsil is the v-groove type because the vendor had it laying around and made me a deal, and was much quicker to get. I filled the grooves with cal-sil blanket, because why not. 2nd layer is the solid block.

i put a layer of foil down to keep it dry until everything is done.

i will extend the floor under the dome bricks. I’m realizing I will likely never need to replace this floor.

im finding I will need a layer of sand/fireclay to level everything out. Question: do you put this down dry, or mixed with water? And, is sand/heat stop ok to use instead?

If not, I’ll need to call around for fireclay.

[UtahBeehiver]

CaSi board too water absorbent for a sand/fire clay wet slurry mix. You can use a dry mix but only if you really need to. Lay down with a notched trowel, like laying thinset for tiles. FYI v groove CaSi is fine, just made to go around pipe.

[fhausback]

Alternatively I could sand down any uneven spots. We’re talking 1/16” difference.

[UtahBeehiver]

You could but CaSi is really friable (crystalline silica) and not the best stuff to be having fly around in the air.

[fhausback]

I meant: sand down the fire brick corners after they are in place

[fhausback]

I decided to lay down a thin bed of mortar to level out my floor brick. I’m only 1/2 way done, please let me know if I’ve made a horrible mistake.

The foil is keeping the calsil dry as I work and keeps it away from the mortar. Even when intried dry-laying my brick the foil was tearing a bunch. I do not think it will provide a long term moisture barrier, but I do think it helps during construction.

I have 2 of my stainless tubes placed and firecaulked in. Drilling a 1” hole in the back of the bricks to receive the tube and thermocouple was pretty easy.

i did also discover that you can over soak the brick. I left a few in water too long before setting them, and the corners chipped as I tapped them into place.

[UtahBeehiver]

How come you don't ask the question first rather than halfway through? The brick floor should be free floating (no mortar) to accommodate expansion and contraction also the first course should "NOT" have mortar on the bottom joint for the same reason. Leveling is accomplished with a 50% sand and fire clay mix either wet or dry which I posted in #39.

[fhausback]

What’s the thinking when comparing The mortared Dome bricks to non-mortared floor? That is, why is expansion more of a concern for the floor? I went ahead and mortared the floor since I saw those that use the Australian kits do that, and it looks like some commercial ovens mortar the floor. Also, I struck out finding fireclay after checking 5 local masonry suppliers.

Would the mortar expand/contract with the floor bricks?