To cement or not to cement...

OK... So I rebuilt the old stove instead of buying a new one. I am going to try and get another six months out of this one. So, here is my question.
The stove exhaust is the type that you must ovalize 8". In the past I have just ovalized the black single wall and placed it tight into the conection. I am curious if I should stove cement/caulk this conection or just continue to jamb it together? (I have never had smoke from this connection in the past, but...) Ehat do you think.

BTW the stove is the Washington Stove Works knock off of the VC Defiant origional.

If it's the setup you've always done, and it's been drafting fine, I think you should be ok. If you want to be absolutely sure of the connection, then I would cement it. The exhaust is under negative pressure due the the escaping gases up the pipe, so it would be pulling air IN through any gaps. In theory, cementing any gaps would improve drafting as it's that much more air it has to pull from the stove rather than any leaks.

The problem would be if you experience any downdraft, or the burn gets to the point where drafting would be minimal (towards the end of the burn cycle when all the coals are dying out) that extra bit of sealing can help keep any unwanted fumes/smoke from escaping into the room.

Ahh! Thanks Bro' Bart. Never thought of that. I will cement it.