Round Clay Flue install question

[jbarnes]

I am at the hearth build stage of my 42" oven but looking ahead to next couple of steps and would like some advise on my proposed use of a round clay flue. My build is an iglo and to be finished with stucco and would like to cover flue with same material. My plan is to cover flue with 1" insulation, wrap with chicken wire or lathing metal and then stucco. Not just for appearance but to ensure the chimney stays warm for a good draft. Any thoughts/suggestions?

[cleverdick]

I guess it all depends on the diameter of your clay flue pipe, but why not put a stainless steel tube inside, held central by a layer of ceramic blanket? That way you would retain the appearance of the clay pipe and it would remain cool on the outside. (You would avoid problems with condensation, too.)

I was lucky enough to find an old clay drainage pipe of about 200mm diameter, and a second hand stainless steel flue pipe of about 150mm diameter. I'm getting a welder to weld a square plate at the base of the steel pipe, which will sit on the oven, sealed above and below with a fire rope gasket. Therefore the clay pipe will not come into contact with anything hot. This is necessary in my case because the roof of the enclosure will be tiled and I will have to use a weathering slate with PVC cone to fit round the chimney, and obviously that can't be allowed to get hot.

No doubt there are calculations for the optimum flue length/diameter etc., but I had to use what was available and hope for the best! (I also coated the outside of the pipe with brick waterproofer - a clear solvent-based fluid.)

Good luck...