A new Folly at Full Moon Farm-- build thread

[WarEagle90]

Retaining wall looks good. You’ll look back on the time spent doing that and be glad you did. Looking at your floor layout, it appears that the center of the dome falls at the intersection of three bricks or very close to it. You may want to consider laying the floor out in such a manner that the center falls in the center of a single brick. That will allow you to remove the brick and fabricate a wooden replacement to attach your IT to during construction. Just a thought. Looking forward to watching our oven come to life.

[rwiegand]

Thanks, I hadn't thought about anchoring the IT other than screwing it to the zipwall sheet I made to lay out the dome and then protect the floor from falling mortar. I'll try to nudge things one way or another for better placement.

I was planning on swapping cut off ends of bricks to make some of the smaller pieces, I just laid it out with full bricks for now to be able to draw the circle.

I guess I should read up on thermal breaks now, I see many people are including them.

[rwiegand]

Is my vent landing the right size? Lots of builds seems to have about a brick and a half of depth, but there are also many comments about many ovens having a "too deep" vent landing. Right now I'm at 14" from the front of the oven to the front of the reveal. The FB plans say 8" of depth, but it's hard to see how you then have enough area for the flue, especially if you use a10" clay flue. It might work I guess if the chimney were set back partly over the dome instead of over the vent landing. It would be easy enough to make it smaller now if that's the right thing to do.

There als appears to be divided opinion on the soldier course, with the argument for being better ability to use all of the oven floor with a small vertical height before the dome begins, and the argument against being that it is weaker construction. Have domes actually collapsed or suffered structural damage because of failure of the soldier course? I was going to cut the soldiers down to about 6-3/4" tall, giving me the equivalent of two horizontal bricks above the floor, in the interest of keeping the top of the dome lower.

[UtahBeehiver]

From an engineering perspective, there will be an outward load from the dome at the point where the dome and soldier meet vs a full hemisphere dome. Somewhere in one of the posts on the forum there is a white paper on loading aspects of different type of arches..

I cannot tell from the pics, but in order for the dome to meet the arch in the upper courses, the initial arch (at the floor) set back needs to intersect the ID arch of the dome. This is critical in order for the IT to work. I marked up your pic where the dome arch and the floor ID arc should intersect. This is especially important when doing a tapered inner arch.

[rwiegand]

Yes, I think I see. You want the inside of the inner arch to be a continuous part of the hemisphere of the dome. That would suggest that the stack of bricks that form the reveal for the door should be getting longer as they pile up to allow a perpendicular face for the door to rest against on the outside, but a curved shape on the inside. Hence your earlier comment about wanting longer bricks for the top of the arch. The light (perhaps) begins to dawn. I'm a woodworker and usually pretty good at 3-d thinking, but these intersecting arches are giving me a headache!

I'd better get on with making my IT. I was going to anchor it by drilling a hole through the slab and using a piece of all-thread so I could adjust the base height exactly, putting the pivot point at the final floor level without having to worry about added wooden blocks and false floors. I figure I can use the hole later for a thermocouple.

Russell, looking at you pictures it seems your vent landing is about 11-1/2", is that correct? (A full brick plus a brick on its side, 9" + 2-1/2")

[UtahBeehiver]

Tapered inner arch concept can cause major brain cramping to visualize but well worth the effort. I have walked a number of builders through this concept and have never had one say I wish I had not done it. All of a sudden the light bulb will come on..............aaah.

I just walked out to my oven and measured my vent distance 9.5"

[rwiegand]

Thanks Russell! You're a real treasure to this community!

[WarEagle90]

Thanks Russell! You're a real treasure to this community!

I'll second that opinion

[rwiegand]

So to fit the inner arch to the dome, it should sit with its base (or where a plumb line dropped from the top of the arch) would make a tangent to the outer circle of the dome. Have I got it right?

Or does it need to set back further, as in Version 2 so the tangent is to the inner edge?

[UtahBeehiver]

The two left and right upper corners of the vertical stacked arch bricks should intersect the ID arc of the dome, in version 2 the lower left and right corners of the arch intersect the OD of the dome, Still need to move the vertical bricks back a little more. The IT sets the ID of the dome.

[rwiegand]

OK, got it, thanks!

[rwiegand]

Progress was slow this week due to other aspects of life taking priority and analysis paralysis over placement of the door. With Russell's help I hope that is now behind me and I can get on with it. I built my inner arch form and my IT, which now make it pretty obvious where to put the door. I've cut and placed the insulation, laid out the floor, and installed the IT. I've been talked out of the traditional soldier course and will lay a couple of sailor courses to give me about 4-1/2" of vertical before beginning the hemisphere. Next up is to build a "Chipster" jig for compound the bricks

[rwiegand]

Progress! After staring, measuring and fussing I completed cutting and installing my soldier course equivalent. It went pretty well, though I didn't manage to keep my bond even around the circle, for reasons I don't fully understand-- all the bricks were the same for all three courses. Minor variation in mortar thickness, I guess.

What's the usual pot life of mortar? I'm using Heat Stop 50 and I could barely get around one circle before it seemed to be starting to set up, maybe 20-30 minutes. For the future I'll be doing one ring at a time probably, so this will work out fine, but it seems short to me.

Using the spreadsheet calculated brick angle it wasn't going to be possible for the bricks to be touching at the interior of the dome, I ended up with ~1/8" mortar lines.

[rwiegand]

My brick work isn't nearly as nice as many I've seen on this site. I keep telling myself that as long as it is structurally sound the pizza won't care how neat and precise it is. I think I'm finally getting the arch integration geometry in concept; cutting the bricks to fit exactly is still giving me fits.

[rwiegand]

Haven't posted for a while, but have been making progress. I have to fess up and say that I have given up on ever being inducted into the pantheon of FB beautiful oven builders. In trying to cut the bricks for my arch I found that I simply could not look at at a three dimensional space and cut a brick to fill it exactly. No amount of measuring and marking seemed to help. I knew what I was trying to accomplish, but couldn't get the hands and eyes to do it. So the inside of my arch is fugly. And I'm not going to show any pictures of it because it's embarrassing. I think it will not fall down, and I'm hoping the pizza won't tell. If anyone wants to come inspect that inner curve with a mirror or inspection camera they're welcome to, but will get no pizza.

Looking forward to closing the dome in the next several days, and then on to the vent.