How much crack is too much crack?

[aikitarik]

Originally Posted by janprimus

I dont know that I recommend it or not, I was just saying I didnt think it would rust. Did you ever see a rusty piece of smoked salmon? ;-P

Well, no, but I've seen plenty of rusty metal flues and dampners. I think I'll stick with my original plan of placing structural steel framing outside the chimney and finding a way to tie them together (mortar or screws).

[Marcel]

(#82)

(M) I wouldn't worry about rust as the re-bar will be covered with mortar on the inside of the flue liners. I don't think civil engineers worry about rusting re-bar inside their prestressed concrete re-bar reinforced slabs, nor the iron I beams in skyscrapers.

(M) I also don't worry about differences in thermal expansion. We all have rebar in our refractory hearth layer. Also, the temperatures in the flue liners will probably be way below that of the dome.

(M) Having said the above, I think it is probably fine to use the re-bar on the outside but in my case, because my liners are sitting only on 2 pieces of flat iron, I don't want to add unnecessary weight by cladding my liners, so mine will be mounted inside imbedded in a bead of mortar in each corner.

Ciao,

Marcel