Smoke Stack Pipe Orientation

[djhcatony]

Folks,
I have yet another first timer question for you. I have had wood stoves for 40 years now and always understood that the crimped end of the stove pipe faced downward. In other words, the crimped end nests into the top of the section below. I think this is to ensure that you don't have a corrosive liquid like creosote running down the outside of your pipe. When I put up my roof jack today and went to set up stovepipe, the only way it would work was to insert the non crimped end of the pipe on top of the base stack. This puts the crimp facing up. I am working with a used evaporator and the old pipe came along with it. The diameter of the base stack looks to be 6" but the evaporator calls for 7". The used stovepipe I also got with the evaporator is 7". I know that you probably don't generate much creosote at the evaporators' higher temps but makes me nervous going against what I have always done. Am I off base here and worried for no reason? Right now, am thinking it's best to replace the base stack with a 7" one as soon as possible.
Thanks in advance for guidance,
Dan

[maple flats]

It seems that evaporator companies don't fully understand the proper orientation for a stack pipe. I just ordered a new SS base stack and all SS stack up from there, it came like yours. I tend to think it's because it is simpler to just taper the base stack and then set a non crimp end on top and go from there. I had a tin shop rebuild my base stack, make an adapter to start from there and go up, to fit each new section into the top of the lower section. That just makes good sense, and besides, I was in the furnace business for almost 20 years and specs always had the crimp facing down and inserting into the non crimped lower section. It then channels any gobaldy gook down inside and not down the outside to look nasty. On the plus side an arch makes no creosote because it never smolders, but there can be stains escaping at the joint when reversed.
Some have argued that with the crimp facing down it creates a resistance to flow, I say, if that concerned them, the top of the base stack, stated to be 12" on mine and supplied with 12 pipe up, would not have been reduced to 10.5" in diameter. My tin shop made it 12" and then made an adapter, about 1' tall to insert into the base stack and give a nice neat connection to the stack going up. The adapter has enough shoulder to support the weight properly. I don't believe the crimps down would make any difference in flow on a properly sized stack, the velocity just isn't there.
I will always run my crimps facing down and inside the lower section.

[Rosser's Ridge]

I'm really new at boiling sap, but I too have been brought up with wood stoves including building 2 boilers. I was taught crimped end up so heat and flames can't escape out seams. yes creasode can run down , but better than flames coming out. Just my 2 cents. I an now goin to build my own arch and have some big ????'s. I have a tank 45" dia x 50" long. my pans (2) are 24" x 48" with 3 dividers. Do i cut tank to fit both pans on side by side with slight overhang loosin some effeciency or cut tank to fit one pan?

[Michael Greer]

I'm in the crimped end down camp, and want to add that you be sure and screw all the sections together well. It's way to big a fire to have a problem with, and you don't want any distractions when you're in the middle of cooking.

[The Sweet Spot]

I have seen this before. You can get an adapter from your local sheet metal shop.

[sugarsand]

I agree with the crimp down theory most of the time, but I put our stack in permanate with crimp up so that rain water cant get in .

[djhcatony]

Sounds like we are split on crimp up or down but takeaway is that no matter what the orientation, make sure that connections are secure. Thanks for all the feedback!
Dan

[Daveg]

Off topic, but is it ok to use metalbestos pipe? Will it tolerate the temps coming out of an airtight 2x6?
Thanks.....

[maple flats]

Yes it will. While most producers use single wall pipe and then design something to protect the nearby wood, any Class A chimney pipe will do fine.

[Daveg]

Awesome. Thanks!
Regards,
Daveg