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-   -   Fireblock Chimney (http://www.fornobravo.com/forum/f9/fireblock-chimney-17885.html)

dolijr 06-11-2012 12:27 PM

Fireblock Chimney
 
So I ended up with a lot of left over fireblock and I was wondering could I just build the chimney out of fireblock and cover it? I looked through the forums but I couldn't find anyone who did it that way.

The oven is outside and the chimney is only going to be about 5 foot tall.

Any help would be appreciated!

azatty 06-11-2012 07:25 PM

Re: Fireblock Chimney
 
Yes, you can do it, but the turbulence caused by the joints and rough brick messes up the draw, and it won't clean as easily as a lined chimney. With a wide enough chimney, the draw isn't much of an issue, though. And it's more bricklaying. I was pretty tired of it when I got to the chimney.

Also, I don't know that I'd try to adhere anything to the outside of the firebrick because of the temperature extremes in the chimney. You'll be at 400 at the top of the vent, and that soaks into the firebrick and radiates to the outside. If you have mortared decorative facing to the firebrick, it could fall off. I would build an air gap between the firebrick and the exterior.

Furthermore, it may be cheaper to buy liner if you don't have a lot of brick laying about (like 36 to 72 bricks).

Gulf 06-11-2012 07:50 PM

Re: Fireblock Chimney
 
Quote:

Originally Posted by dolijr (Post 132957)
So I ended up with a lot of left over fireblock and I was wondering could I just build the chimney out of fireblock and cover it? I looked through the forums but I couldn't find anyone who did it that way.

The oven is outside and the chimney is only going to be about 5 foot tall.

Any help would be appreciated!

I'm not sure if fireblock are the same as fire brick but, I built my liner out of fire brick. Set a gap between the liner and the face brick and filled the void with vcrete. To figure it for an 8" ID flue: that is 5 fire brick per row, 3 rows per foot, multiplied by 5 feet = 75 fire brick. Compared to the dome and entry not very difficult.

note: My chimney has not seen live fire as of yet. Just a prototype, but I don't forsee any problems :).

deejayoh 06-11-2012 11:24 PM

Re: Fireblock Chimney
 
Quote:

Originally Posted by azatty (Post 132996)
And it's more bricklaying. I was pretty tired of it when I got to the chimney.

that comment made me laugh pretty hard :D. I know exactly how you feel.

FWIW, Clay flue pipe is probably much cheaper than firebrick, unless you bought it already and/or got a smoking deal.

dolijr 06-12-2012 06:58 AM

Re: Fireblock Chimney
 
Quote:

Originally Posted by deejayoh (Post 133011)

FWIW, Clay flue pipe is probably much cheaper than firebrick, unless you bought it already and/or got a smoking deal.

I ended up with way too much brick and they are going to charge me a 20% restocking fee to take the block back, so i am stuck with a lot of extra block. I roughed it together and have enough block to do a 5 foot section and I basically wasn't planning on doing a lot of cutting, since that is the worst part.

I just haven't seen anyone use this model and I was wondering if there was any disadvantages.

deejayoh 06-12-2012 12:25 PM

Re: Fireblock Chimney
 
Quote:

Originally Posted by dolijr (Post 133027)
I ended up with way too much brick and they are going to charge me a 20% restocking fee to take the block back, so i am stuck with a lot of extra block. I roughed it together and have enough block to do a 5 foot section and I basically wasn't planning on doing a lot of cutting, since that is the worst part.

I just haven't seen anyone use this model and I was wondering if there was any disadvantages.


You'll definitinely need to overbuild your arch to support the weight of all those bricks. For ideas, I'd suggest taking a look at Gulf's "Mississippi Queen" build. A serious masterwork of masonry.
http://www.fornobravo.com/forum/8/mi...tml#post127324

Gulf 06-12-2012 07:58 PM

Re: Fireblock Chimney
 
deejayoh,
Thanks a bunch :).

dolijr,
IMO I think that a five foot 8" ID fire brick liner (as I described) can be placed on a typical arched entry, as long as it is buttressed. I did not place the weight of my chimney liner on top of the arch, though. If you look back at my build you will see that I placed the weight to the outside. That was because I built an unusually large entry/fire place/smoke chamber to be used for multi-purposes. The weight of the oven is placed on the the 2" calsil layer. The weight of the flue and chimney is transferred to the 4" of vcrete. The weight of the face brick is transferred to the hearth slab. The liner and the face brick with the vcrete insulation between are one unit, but they must be treated separately.
Also, I think that I read that you were tired of cutting brick. If so, my advice is to buy an insulated SS liner or take a break before you continue :).


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