Vent material debate! Clay vs Stainless

[Aegis]

Ok, I am at the point of doing my flue and have seen many a flue cut diagonally and then mortared together to make a funnel type vent.

Questions:
1) In personal experience has the mortared flue separated due to thermal stress or other reasons?

2) Is there and advantage of the insulated stainless steel vs the refractory flue?

I have purchased refractory flue pipe 8*8 for my oven for two reasons:
1) it will outlast my grandkids!
2) it was much cheaper!

Did I make a poor decision?

Thanks
John

[Tscarborough]

Re: Vent material debate! Clay vs Stainless

No, you made a good choice.

[Aegis]

Re: Vent material debate! Clay vs Stainless

No, you made a good choice.

Thanks for the vote of confidence in the clay flue, so I take it your flue hasn't had a problem. I did go through almost every post on your build many times and always admired your brick work! I am still wondering how you made those curves seem so effortless and smooth. Great Job!
Thanks
John

[dmun]

Re: Vent material debate! Clay vs Stainless

No problems with the pieced together flue tile funnel. We've seen more cracking of whole flue tiles, mostly when builders have used them out in the open where there's big thermal difference between inside and outside.

Flue tile is cheap, but by the time you've built an enclosure for it, your cost advantage disappears, particularly if you consider your time worth anything.

I mostly don't like the look of stainless flue systems, that's why I built a masonry chimney.

[Aegis]

Re: Vent material debate! Clay vs Stainless

No problems with the pieced together flue tile funnel. We've seen more cracking of whole flue tiles, mostly when builders have used them out in the open where there's big thermal difference between inside and outside.

Flue tile is cheap, but by the time you've built an enclosure for it, your cost advantage disappears, particularly if you consider your time worth anything.

I mostly don't like the look of stainless flue systems, that's why I built a masonry chimney.

I have had stainless steel double insulated flues before on a coal stove. I understand that there is a LOT of sulphur from a coal stove and when it gets wet, it turns into sulfuric acid! A flue would only last 10 years, I don't want to take a chance and have to replace the flue in ten or fifteen years. More like never, is a good time frame. I know wood doesn't have the sulfur, but if you do want to burn coal, ala Pepe's Pizza New Haven Ct. then this would be an issue. The mositure gets in the pipe during the hot HUMID weather in Ct. Maybe in drier climates it would not be an issue.
Dmun, your build is exquisite and OH so complex and complicated! WOW again!
Thanks for the input!
John

[david s]

Re: Vent material debate! Clay vs Stainless

A third alternative is to use a castable. It has an added advantage of easily creating a complex funnel form.

[Cheesesteak]

Re: Vent material debate! Clay vs Stainless

I went with 8x13 clay flue liner - and when my oven is going it draws like a wind tunnel. I didn't cut the liner - i simply stacked them with a thin coat of mortar in between. Works great.

The steel pipe is almost certainly easier - and, like dmun said - the cost savings really don't matter when you consider the need to enclose the flue liner. Just do whatever "feels" right to you . . .

[rodeair]

Re: Vent material debate! Clay vs Stainless

I am at the point of having to decide on my vent/chimney system. I will have an enclosed oven, so whatever I put in there has to last well. After lots of research, I've decided on Selkirk Metalbest Class A pipe, (much the same as Duravent). The stainless inside, galvanized outer wall ducting is alot cheaper than Duravent. After looking online at the deals on Ebay, etc., I'm hoping to get a good deal. I'll need a anchor plate, 30 degree elbow kit, 3 ft length, 4 ft length, and a chimney cap. All told, about $650 if I'm lucky.

Leigh