Chimney Question

[Kelbor]

Hi everybody,
I am building the Pompeii oven (I think) and am trying to get the chimney/vent right. My interior oven dimmension is 36". Door is 19" wide and 12" tall. My chimney opening I have created in the entrance arch is 10" by 6" square. The question I have I guess is; Do I need to "flare" the base of the chimney (so it constricts on the way up)?. Also, what height should I be shooting for in order to ensure I get good draw. Lastley, does my flue liner need to continue to the top of my chimney stack or can I switch to regular brick at the top.

I found one 10" by 6" liner that is about 12" tall. I was planning on building a base from fire bricks with high temp mortar on top of my entrance arch to create a flat location for the liner to rest. Then after setting my liner on the new "shelf" I plan to wrap it with ceramic blanket. Then I was going to continue to enclose the flue/ceramic blanket with ornamental red brick splits to hide the ceramic blanket, thus giving the flue room to expand and contract as needed within the structure without popping off the pretty bricks. Is this standard operating procedure?

Any help or advice would be greatly appreciated. Thanks All!

[dmun]

Re: Chimney Question

Do I need to "flare" the base of the chimney (so it constricts on the way up)?

I think the best practice is to have an opening in your entry about twice the area of the flue opening. Having no transition is a potential problem of smoke coming out. My smoke funnel may be a bit excessive: with a two story chimney it could probably contract at the bottom and still draw fine.