Chimney Primer

[mikes334]

Re: Chimney Primer

I found everything, including a chimney cap, for my duratech chimney project at chimney liner depot.

[karl]

Re: Chimney Primer

Hello Shay.

There is a picture of my build in this thread which shows the chimney hat I have installed. It is predesigned and sold by the vendor which provides the standard chimney bricks. But it is a simple design. I guess you could also consider to use natural stones (slate?). Just remember to hav a few cm gap between the end of the inner flue pipe and
the hat (for lenght expansion).

karl

http://www.fornobravo.com/forum/attachments/21/8727d1220823448-first-milestone-passed-oven1.jpg

[blacknoir]

Re: Chimney Primer

Forgive my ignorance but does anyone have a picture of a suitable hat that can be used to go over a clay flue and brick chimney? everything I've seen just covers the flue and not the surrounding space between the flue and chimney..

[karl]

Re: Chimney Primer

Mike.

I guess vermiculite only will be Ok. The clay flue will need to expand in the axial direction (mainly) so you must allow for movement between the flue pipe and the brick chimney. Radial expansion is not enough to worry about. Why fill anything in the void. Air is by far the cheapest "fill"!

regards from karl

[mfiore]

Re: Chimney Primer

Karl, what about filling with vermiculite/concrete insulating material that is used to cover domes? Would that be compressible and allow for expansion (seems to work over domes)?

[karl]

Re: Chimney Primer

Hello Shay.

You definitely do not want to fill that void with cement! The clay flue need to move as it will expand during heat-up. The void is normally air-filled (sometimes filled with stone fibre wool) and the closing of the void is done on the top of the chimney by a suitable hat.

The closing also need to take into consideration the lenght-increase of the clay flue when heated.

regards from karl

[blacknoir]

Re: Chimney Primer

If you build a brick chimney around a clay flue, do you fill the 1" gap around the flue with cement or something else? Or is there some other way to keep water from dripping down between the flue and chimney wall?

[Lars]

Re: Chimney Primer

I am still wondering about the arch/support flue weight issues.

I had an issue with my front arch ( which will support half the weight of my flue -- a 2' section 8.5x13" ) but I am buttressing it with bricks on either side!

I think I am going to just try a mortar/firebrick transisition ( I am pretty sure smoke will not be so laminar it will need a smooth smooth surface) and, though rounded edges would certainly help ( in theory) I am betting that the smokes gonna go up at the first opportunity ( my flue) any way it can.

L.

[Harvybing]

Re: Chimney Primer

What about an indoor fireplace with openings on all 4 sides. I've seen some but don't undertand how they insure that they draw correctly. Anyone have any experience on these?

[dmun]

Re: Chimney Primer

I'll have to look closer at my box store for clay parts

No, you'll need to go to a brickyard for the flue tiles, but they sell the caps at home depot. they are more of a mass market item because the old ones rust out.

[blacknoir]

Re: Chimney Primer

Heh, I'm in a suburb of MN and it's all metal pipes and caps around here. Some of the local farms might be a different story. I'll have to look closer at my box store for clay parts, figured I'd have to go to a special store for those.

[dmun]

Re: Chimney Primer

Absolutely, they're right on the shelf at home depot. They clamp to the corners of the flue tile. Look around your neighborhood, you'll see half a dozen on peoples chimneys (the keep birds and squirrels out)

That said, I have yet to put one on mine. I should: some soot washes down in rain and makes my landing unsightly.

[blacknoir]

Re: Chimney Primer

Any idea if they make a tile spark arrestor cap? I really like those clay caps but I should probably get a cap with a spark arrestor to be safe. My WFO will be right next to a large wooden deck and the chimney will run either through a pergola or be right next to it.

[dmun]

Re: Chimney Primer

There's no reason not to build the entire chimney in the traditional manner, with the flue tile interior, a masonry exterior, and a chimney cap to keep them aligned. I see no reason to mix the two styles. The stainless flue systems are for people with more money that time, not that there's anything wrong with that.

An eight inch square flue tile is big enough for any domestic oven.

[blacknoir]

Re: Chimney Primer

Holy Cow that DuraVent is expensive isn't it.. especially if you need 4+ feet of it to go through a pergola which I also have to do. 2 more questions. First, did you guys go with 6" or 8" pipe? Second, any reason not to do a clay liner, if it's cheaper, for the first few feet and then switch to DuraVent?