Starting new 36" build

[GianniFocaccia]

Re: Starting new 36" build

On the IFB - I saw a comment you made a while back suggesting that it might be tough to get the mortar to stick to it. Do you have any more background on that issue?

No direct experience, but since that post I observed a video somewhere showing a worker bonding multiple yard-long 'columns' of IFB that ended up making a very rigid sheet of material. I also discovered there is such a thing as IFB mortar, so the sky's the limit.

BNZ Materials | Insulating Fire Brick

[deejayoh]

Re: Starting new 36" build

Update: We are experiencing a phenomenon known locally as "June-uary". It's cold and rainy, which means I have not been able to make any progress on my vent arch.

So that has given me lots of time to think about my approach, and to focus on identifying sources for what remaining supplies I need. Here's what I have decided to do:

Heat break
+ At the back (dome side) I have about a 1/2 inch gap between the vent arch and the dome arch. I am going to stuff that with a 3/4" length of ceramic fiber twisted braid - typically used as kiln gasket. This won't be exposed to any flame, so it should be ok
+ Inside the arch, There is about a 1/4" gap between the dome arch and the vent arch. I am going to fill that with Kaowool moldable. It looks like it should easily handle the temps - and since I have a relatively narrow/deep slot - I don't think it will ever work its way out once it is in there.

Entry floor
+ For the break between the oven floor and the vent floor, I decided to go with a piece of 0.5" x 1.5" Stainless rectangle tubing. I am going to cut the bottom of it away, except for at the two ends. It will basically be a channel, except I'll leave about a half inch of material at each end so that will sit level. I found a supplier for this right down the street, so decided to stop shopping!
+ For the entry floor itself, I found an installer with scraps of soapstone from whom I can get a piece cut to fit. I figure it will probably be 2 cm thick
+ Under the soapstone, I am planning to use IFB splits. I am still debating this, but I don't really see any benefit to using firebrick. I don't need the entry floor to be hot, and I want less mass to pull heat out of the oven. Plus, the IFB is easier to cut to exactly the height I want, less prone to crumbling/breakage, and I already bought it

Enclosure
+ I am going with the "doghouse" style. I really like the dimensions of Smuth10's oven - so am going to sketchup something like that for the roof pitch and height.
+ I've decided to use cultured ledgestone drystack (lick and stick) for the bottom, and stucco the top. I will probably also do a faux chimney detail in the front to break up the space
+ I'm going to use trim stone that matches the drystack for the decorative arch
+ the roof will be standard tab to that matches my house
+ I plan on pouring a concrete counter at the level of the oven entry

Chimney
+ I already purchased 8" Duravent anchor + 24" stainless pipe + cap.
+ I plan to build a chase for it and cover with the same material as the base
+ Duravent has standard chase covers available for their dual wall, so that is going to dictate the dimensions of my chase
+ I went with the chase vs. having the stainless go through the peak for both aesthetic and cost reasons. Through the peak flashing for round pipe is very pricey, and I don't really like the way it looks.

Lots more work to do, that is for sure! I would love any feedback on my plan. I didn't mention stuff like dome insulation - but it's on my checklist too.

[deejayoh]

Re: Starting new 36" build

No direct experience, but since that post I observed a video somewhere showing a worker bonding multiple yard-long 'columns' of IFB that ended up making a very rigid sheet of material. I also discovered there is such a thing as IFB mortar, so the sky's the limit.

BNZ Materials | Insulating Fire Brick

I can report back that the mortar seems to be sticking well to the IFB. I am using it as part of the buttress for my entry arch.

The arch is free standing from my dome, and I have about 2 inches of insulation that extends beyond the edge of my arch on each side. For the buttress, I mortared 2 IFB to each side of my arch over the insulation. Then I am going to mortar a 8" x 8" cinderblock to that firebrick and to the concrete hearth . That way, my arch is effectively buttressed to the concrete base, but there is a layer of IFB between the arch and the cold concrete that should keep it from losing too much heat into the base.

Since my entry arch is already isolated from the dome, I wasn't too worried about finding a perfect solution - but thought this was better than using a more heat conductive material for the buttress.

I also thought that if the mortar connecting the IFB and the arch doesn't hold, there should still be sufficient tension between the arch and the cinder block that it will serve it's purpose.

[deejayoh]

Re: Starting new 36" build

Lots-o-progress this weekend: Entry arch completed and buttressed (is that a verb?); flue completed and chimney fitted; huge mess is backyard mostly put in garbage bags.

Right now I am curing with a worklamp, but it only gets up to ~100 degrees. Think I will borrow Tu's idea and use Chafing fuel for the next stage of the cure.

Just need to get the soapstone & stainless tubing for the entry, and refractory caulk for the heatbreak this week and the oven will be complete.

[Amac]

Re: Starting new 36" build

That looks fantastic Dennis - I know you said this isn't a race but I think someone just flashed past me on the finishing straight. I really hope that buttress is over engineering because it never even occurred to me that my entry arch would need buttressing. Hard to resist lighting a few fires in there I'd say, but take your time - the longer the mortar has to cure the better.

[texman]

Re: Starting new 36" build

Dennis

Great job.

Tracy

[deejayoh]

Re: Starting new 36" build

That looks fantastic Dennis - I know you said this isn't a race but I think someone just flashed past me on the finishing straight. I really hope that buttress is over engineering because it never even occurred to me that my entry arch would need buttressing. Hard to resist lighting a few fires in there I'd say, but take your time - the longer the mortar has to cure the better.

Thanks Aidan. I am pretty happy with where I am. I added the buttress because my arch is free-standing from the dome in order to provide the heat break. I seemed pretty solid as a "unit", but the whole thing would rock slightly on the FB Board. The buttressing was intended to stabilize the arch, and it seems to have done the trick. No movement any more.

As for the curing, I hear what you are saying! I wanted to throw a few wood scraps in there last night and fire it up - but I resisted. The mortar in the dome has been air-curing for 2 weeks, but the mortar in the arch is pretty fresh.

I've left the quartz lamp on in the dome 24 x 7 for a couple days. The temp inside ranges from ~90 - 170 degrees (bottom to top) and the dome is ~85-90 degrees on the outside. Tomorrow night I am going to try to get that up in the 250-300 degree range inside using the chafing fuel. Because of the heat break, I don't think that will get the arch much warmer than ambient temps.

I think I will be ready for first fire next sunday if I can stick to a schedule of +~100 degrees each night this week using the chafing fuel

[deejayoh]

Re: Starting new 36" build

Wow! I wrapped the oven up in a tarp this morning because I thought it might rain before I got home. Came home late and checked the temps, and with just the lamp the interior is over 250 degrees. A little insulation goes a long way!

[SCChris]

Re: Starting new 36" build

dejayoh, Are you still using a quartz lamp or did you go on to chafing fuel?

Chris

[deejayoh]

Re: Starting new 36" build

Chris -
Still just the lamp. The temp was 250 at the dome peak only. The floor is around 120-130 degrees. Per the instructions in the FB guide, I think I am going to unplug the lamp this morning to let the oven cool down, and then start with the chafing fuel tonight.

[SCChris]

Re: Starting new 36" build

Slow and steady are your marching orders. It's Tuesday morning and depending on how you move forward, by the weekend you'll be able to roast a chicken. I don't quite remember how fast banhxeo76 cured with chafing fuel, but at 100F or so per day a chicken is doable for Saturday dinner for sure.

Slow heating and soak the dome with the heat!

Chris

[Tscarborough]

Re: Starting new 36" build

Looks good, and I can think of nothing better for Father's day than hard labor. And Beer. Lay a 2' piece of rebar at 45 degree angles across those inside corners, if not 2, and/or cut a control joint across them.

[Amac]

Re: Starting new 36" build

I added the buttress because my arch is free-standing from the dome in order to provide the heat break. I seemed pretty solid as a "unit", but the whole thing would rock slightly on the FB Board. The buttressing was intended to stabilize the arch, and it seems to have done the trick. No movement any more.

Ok of course - makes sense now! I did a roast in the WFO last Sunday which was perfect. Tried to make some Ciabatta bread afterwards. Tasted Ok but I think I could use the result as a weatherproof cladding - after a few days it is tougher than buffalo hide.

[deejayoh]

Re: Getting started

After contemplating and planning for over a year, my build has begun, I have set the forms and laid the gravel. next step 6 mil plastic, rebar then lay the cement. I think pouring the cement this Sunday on fathers days is the best gift to myself....(the wife thinks I am nuts!!)

Looks good - but you'll probably want to start your own thread on your build

[jlopiccolo2]

Re: Starting new 36" build

thanks for the advice Tscarborough....much appreciated