42" Corner Build in Southern Missouri

[Buzzard Bluff]

Thanks Russell, I have a smaller end for the IT ready on standby. I remember studying your build years ago when this crazy idea first came to me. Your detail and professional results have been great examples of what an amateur can only shoot for.

2 questions for anyone...

1. When finishing the last part of the top of the dome, what can be used as a brace to hold the final bricks in place? I was thinking some kind of ball or a gently curved sheet of metal??
2. On the outside of my dome I'll have 6 1/2 inches available for insulation before I'm at the edge of my concrete base. If I need 1/2 inch for the final stucco coats that leaves 6 inches to insulate the dome. Does 3 inches of ceramic blanket followed by 3 inches of perlcrete sound adequate?

Steve

[IH123]

Thanks Russell, I have a smaller end for the IT ready on standby. I remember studying your build years ago when this crazy idea first came to me. Your detail and professional results have been great examples of what an amateur can only shoot for.

2 questions for anyone...

1. When finishing the last part of the top of the dome, what can be used as a brace to hold the final bricks in place? I was thinking some kind of ball or a gently curved sheet of metal??
2. On the outside of my dome I'll have 6 1/2 inches available for insulation before I'm at the edge of my concrete base. If I need 1/2 inch for the final stucco coats that leaves 6 inches to insulate the dome. Does 3 inches of ceramic blanket followed by 3 inches of perlcrete sound adequate?

Steve

for #1. may be use less water in your mortar (not less than what the mortar bag says) AND have thinner mortar every where (not less than the minimum your mortar bag says) - wet bricks first don't add much water to mortar itself . I used Thermobond 915 and had my bricks cut taper and wedge on all 4 faces however I never needed to support any brick even for the top most one. I mixed very small amounts of mortar at a time and I let a brick stay in the IT for few minutes while the mortar dries a tiny then put next one and they support each others. if all that does not help, then you could get a thin lumber like 1x2 and cut it to exact radius length for the course you are at and put one under each brick

for #2)I am not the most experienced on that however the perclite insulation value is very small, its mostly to seal the dust of the insulation and also protect the insulation from the outside elements and provide rigidity. 2" good quality ceramic fibre blanket is usually enough as long as seams are overlapped so 3" should do very well.

[UtahBeehiver]

I tried the jack/platform idea for the last few courses but I could not see how the inside joints/mortar was looking so I abandoned the idea and went with notched sticks. 3" Ceramic blanket plus perlcrete is a very good amount of insulation. Actually an 8-10 to 1 ration of p/vcrete has pretty good K value but it is a little hard to work with. See attached.

[SableSprings]

Great work Steve! #1 - I cut a piece of plywood and braced it underneath (with shims under the brace 2x4 or 4x4 piece) the remaining dome opening. I then made a mound of sand on top of it to be a support for the last bricks and keystone. Made it pretty easy to close the dome without fiddling underneath each brick. After the keystone was secured in place, I pulled the shims, dropped the support wood/sand mini-dome , cleaned it out and did a cleanout. It was a pretty straight forward process for me since my build was done before I'd learned about the indispensable tool. There are some pictures in my build thread (link in signature line).

#2 - the 3" of ceramic insulation is really all you need...the chicken wire or metal lattice goes over it to support a 1-2" top coat of perlcrete. The wire/lattice layer minimizes compression of the blanket and provides a better adhesion surface for the perlcrete. The perlcrete is primarily to contain any ceramic blanket fibers and to allow you to form a nice dome shape and base for tile or stucco finish.

Remember to add only the ceramic blanket before the initial firing series. That helps reduce temperature shock and allows an easy path for moisture to escape. You're doing fabulous work and on the home stretch!

[SableSprings]

Utahbeehiver is absolutely right on the inability to see the inside mortar joints with the platform closing method. I just wanted to close the dome and tried to be careful not to over-mortar when I placed each brick. My closing and inner brickwork is nowhere as clean and neat as his is and I loved his keystone work, but my oven works (over the years I have come to realize my personal motto apparently is not "Patience is a virtue" ).

I'm pretty sure if I built another oven, I'd do a LOT of of things totally different than I did back in 2009! An incredible amount of innovation and amazing builds on this forum...certainly why I firmly believe this is the best WFO resource on the Internet!