Round shape

[mrchipster]

Re: Round shape

I like that look...very midieval . How will you cover it?

I am also interested in How your roof will be made I tried to come up with a round design that would work and could not come up with a good way to have the chimney exit the roof without leaking.

I changed to a modified delta wing type roof and -- well I am still working on a flashing design for that. May be a combo of saddle and adjustable pitch styles.

Chip

[Mike D]

Re: Round shape

-Well as for the SBC, don't I want it to be water tight? Won't normal brick and mortar transfer rain and moisture into the insulation? I plan on curing the oven with the insulation on (blanket, I have 3 FB boxes), but without closing the top.

-I plan on using as much insulation as possible and making a slight curve on the top. Not too flat that would create a pooling problem, but not too round that it looks like something is trying to get out. The Red brick enclosure is so tall that you can't see the top anyway (I didn't want the roof to show). I was going to curve a couple of pieces of rebar to go over the top and put a piece of some type of wire mesh on top, then stucco the top (or SBC).

-As for around the tile flue pipe, I was going to wrap it with cardboard wile the stucco went on to give it some room for expansion. Then fill it in with high-temp caulk. I have read though different threads that tile flues tend to crack when they are exposed on the top (from having a too hot on the inside and cold on the outside). I was thinking of wrapping the pipe with one layer of blanket and the putting a copper sleeve on the outside, that would connect to the rain cap. This would also give me another opportunity to put a high-temp caulk on the copper pipe/sleeve for keeping water out of the oven. It would be like a homemade double walled flue pipe.

Mike

[Mike D]

Re: Round shape

And thanks for the praise on the Coliseum.

Mike

[mrchipster]

Re: Round shape

And thanks for the praise on the Coliseum.

Mike

You deserve the praise, very nice oven, very creative...

Chip

[Mike D]

Re: Round shape

So, got some work done. I put a couple layers of SBC on the inside of the red brick. That stuff is a little gummy, but you get the hang of it when you get going. It drys up fast, so any one reading this should mix in batches (1/2 a bag at a time?).

Got the rebar and wire ready for the side prep table. I filled the cores of the block almost all the way up. I left about a half a block at the top so I could let the counter top fill in to get it connected. I need to build the outer form and pour the counter next.

Mike

[brickie in oz]

Re: Round shape

Nice enclosure.

Cuppla questions.
What is holding the gather for the flue in place? I feel if left as is it will collapse when it expands and contracts over time.

Also, what are you doing for a roof?

[Mike D]

Re: Round shape

I think it is solid. It was made with ceramic flue pipe. It's mortared on and vertical. I didn't want it touching the outer red brick for those expansion reasons. It will be covered with lots of blanket, then a stucco type cap on the top.
-Why do you think it will fall apart? You can check the old posts for more pictures.

Mike

[brickie in oz]

Re: Round shape

-Why do you think it will fall apart? You can check the old posts for more pictures.

You have 4 small pieces probably no more than 20mm thick that are glued together with mortar, (high heat or not, doesnt matter) the weight of the flue as is with no expansion wouldnt be a problem, but once it all starts to move it could fail.

Id hate to see a fine build fail like that, especially once the roof is one as it would be a pain to redo.

You could maybe pack some refractory concrete around the base where the pieces are, this would at least give it some support if it does move.

[Mike D]

Re: Round shape

-I spent a long time trying to create that flue. Making that transition from that large opening in the outer arch up to a 8" flue tile.

-I could put a layer of high temp mortar over the outside of the flue around the joints, but would that effect anything else. Or would it do anything?

- I hear of these ceramic flues cracking from time to time, and some people think it's from the outside of the flues being exposed (too cold) to the hot interior from the fire.

-I have seen other flues build in pieces like this, have they crumbled?

Mike

[brickie in oz]

Re: Round shape

Sorry I cant answer that, you may have to ask those that have done it previously and see how they went.

Ppl generally wont report the failures.

[Mike D]

Re: Round shape

-Maybe I need a better idea how these things expand. I envision the flue and oven heating up and expanding as a whole. As in, expanding and moving as one piece, maybe the flue and the oven expanding at different rates. Wouldn't the same materials expand the same? As in the flue would heat up and expand, but together. I can't picture how it would fall over.

-Help me out.

Mike

[brickie in oz]

Re: Round shape

The flue would heat much quicker as its thinner than the oven and gets direct heat from flue gasses, I forget what Ive clocked my gasses at, but its something like 600c+.
The two smaller pieces are generally leaning inwards, so in my opinion would tend to want to go that way with the movement of expansion and contraction, they may move over time.
They may also not move too?
If it was my oven Id add some support, just in case.

[david s]

Re: Round shape

Mike,
Very nice work. if it were my oven I would be insulating around the flue. Yes I believe it is the temp difference that is the problem. If you build a layer of vermicrete 10:1 all around the flue it will both support and insulate the flue tiles it surrounds. You can then render/stucco over this. A stainless steel flue pipe does not have the cracking problem a clay one does, so you are best to surround the clay flue tiles all the way to the top. About an inch of vermicrete should be enough.

[ggoose]

Re: Round shape

Mike
Your build is looking great! Very clean and symmetric (and unique ). Could you perhaps enclose the portion of your flue in question with some castable refractory? That would hold the heat and lend strength, if I understand the behavior of the stuff correctly. What is the enclosure you are constructing to the right of the oven?

gene

[Mike D]

Re: Round shape

Thanks for the advice guys,

-I could put a layer of vermicucrete around the flue. I have a small bag of that mix left over, but do you see a problem with the vermicucrete touching the red brick enclosure? There is not much space between them in the front. I was planning on squeezing a fire blanket in that gap and wrapping the entire flue as well to keep it insulated anyway. I was trying to keep the outer red brick away from the flue (not touching) to help prevent a heat transfer. Will that vermicucrete be more of a problem with the red brick?

-I was planing on putting a copper sleeve on the outside of the ceramic flue (which would of been wrapped with blanket), so I could just fill it with vermicucrete.

-ggoose- the side counter is a prep area to build the pizzas on. Underneath it I am going to put a speed rack to have half sheet pans to hold doe and other stuff to keep them out of the way. To the left of that I am building a grill (that used to be there but I demoed so I could rebuild it). Here is an old picture of how it will look when it is done (this was a dry stack).