Clay Flue-Size and installation

[ultrasport]

Just finished my 37" dome and ready to install flue.

My intention is to use a Clay square 8" od flue liner X 36" tall enclosed by firebrick then veneered with thin brick. This flue will go through a wooden roof but open on all sides. Roof will be just to keep rain off dome. My concern is how hot the flue gasses will be and will the clay line be able to hold up to it ?

Logan flue liners say they fire all their flues to 2000 f when they are manufactured.

Any guidence will be helpful. I really don't want to spend hundreds of dollars for an insulated stainless steel flue.

[NCMan]

Any reason why you are enclosing the chimney w/firebrick? You may want to check out your options before going that route.

[ultrasport]

I would be enclosing the clay liner for 2 reasons. 1) I will be going through a wooden roof above the dome with all sides exposed on all sides so you will see the actual oven hopefully keeping the rain out. 2) for esthetics ( my plan to use firebrick then veneered with thin brick/stone)

[NCMan]

It's just that you don't need to build it out of firebrick, if you'd don't want to. Regular reds will do. You can build w/the reds and not have to veneer it. I'd still insulate between, though and use a cap

[UtahBeehiver]

What is unknown, is how the vent entry is configured, a pic would help. If it is a partial arch, IE straight side walls with arch across top and with out buttressing, a clay liner with brick exterior will be REALLY heavy and you may need to buttress the arch area. if is a full arch you may not need buttressing but it needs to be considered. Don;t think cheaper is better or safer.

Agree that insulation between clay liner and brick is recommended. David S has posted a video somewhere on the forum show what temp differential/shock does to uninsulated clay lines.

[NathanR]

There is an ASTM standard about clay flue liner installation excerpted in the FB Pompeii plans:

ASTM 1283 (Standard Practice for Installing Clay Flue Lining):
Flue liners shall be surrounded by masonry on all sides but shall not be bonded to the surrounding masonry. The flue liner shall contact the chimney wall only as necessary for support and alignment in order to permit the flue liner to expand and contract freely. The separation of the flue liner from the surrounding concrete or masonry shall not exceed the wall thickness of the flue liner. Where Seismic Reinforcing requires the space between the flue liner and the chimney wall to be grouted solid the flue shall be wrapped with ceramic fiber paper capable of withstanding temperatures of 2100 deg. F to prevent the flue liner from bonding to the chimney walls.
© Forno Bravo, LLC 2007-2009. All Rights Served.
Ver. 2.0

[CoastalPizza]

I also used a 36" section of 8" clay flue liner in my build. The first try was just the clay flue set over the hole in the arch. That one cracked after a few uses. For #2, I coated the flue in perlcrete, one side at a time, and then in colored stucco. I used more perlcrete to attach it to the oven and then more colored stucco. It has held up for the last couple of years — many firings and a couple of hurricanes! Here are a pictures of the perlcrete application and the finished chimney: