Stack size?

[Brian Kloepfer]

I have a 2X6 arch it is insulated and bricked. I curently have a 6 in stack on it. Would I see a gong in changing to a 8 in stack?


http://i584.photobucket.com/albums/ss287/bckloepfer/New%20arch/IMG_0284.jpg

http://i584.photobucket.com/albums/ss287/bckloepfer/New%20arch/IMG_5168.jpg

[nymapleguy607]

That depends how does the back pan boil now? My arch has an 8 in stack thats 17' tall I get a better boil in the back pan in the very back part. If your evaporator boils hard in both pans then I wouldn't worry about it. The larger stack will just give you more draft.

[Big_Eddy]

What are you feeding your evaporator? Other than the smallest pieces, the wood I see in the background is too big for a 2x6 evaporator. Feed it small dry wood, less than your wrist in diameter, and feed it often. Don't jam it full to the top - build a smaller fire on the grate and feed in an armload every 5-6 minutes. If the woods been consumed in 5-10 minutes, you're wood's sized right - if you have much remaining then you're putting in too much or it's too big.

Stack diameter is primarily sized by arch width rather than arch length. For a 24" wide arch, I'd suggest an 8" stack, but a 6" should do the job if you use small dry wood, keep the air inlet wide open and keep the ash cleaned out under your grate.

[Brian Kloepfer]

Big Eddy I feed my arch shall dry wood like what you described about every 10 min. The wood in the background is for my outdoor wood stove. Thanks for the advice.

[wiam]

My 2x6 came with 10"

[sugarwoodacres]

i just bought a 2 x 5 bilodeau , it came with a 7" stack . I switcthed to an 8" and the thing boils twice as hard now . Was advised by my new great friend Tom Phillips of Hardwick, NJ to split the wood smaller and dont pack it like my woodstove . Stagger stack the wood in firebox, criss crossit and let it get air .

[Cardigan99]

Brian I have a 2x6 and run a 10" stack. Good rolling boil in both pans.

[jake1]

i am currently building a 2x6 similar to yours and am planning to use a 8" but how does the 6" work for you? also are there things you wish you had done differently, like gaping under pan or design in general? how is it working for you? i acctually kind of based my design off yours with just a slight ramp out of the fire box. oh and im wondering if you full bricked the fire box with a blanket or split brick, just dont want my firebox to small after all that insulation, sorry for all the questions but i just dont want to make too many mistakes. thanks
Jake

[Brian Kloepfer]

The 6" stack works but I am going to try a 8" stack next year. I don't get a good boil at the back of my back pan. With that said I don't have a preheat er aether so I am dumping cold sap in the back of the pan. So a preheat er is in store for next year to. I used the insulation board in the hole arch and 1/2 fire brick in the hole thing.

[fishman]

Brian-I made my arch from your plans last year and used an 8" stack and it boils great all the way to the back of the pan. I use 10' of stack, don't know if it would boil better with more height or not. I do have a small blower for it this year though which should help. Now all I have to do is tap some trees.

[eustis22]

ok, I have a 2 X 3 arch with a 6' stack at 8"

this summer i plan to roof over my boiling area and the stack ends right about where my new roof line will be so I plan on adding 2 more feet of stack....what will this do to my draft?

[justahobby]

I just built a new arch, about 2.5 X 6 or so. Ended up using a 10" dia X 10' stack with air over and under fire blowers. It is a lot easier to decrease the draft than to increase it once you have something built.
Check out this chimney equation here: http://en.wikipedia.org/wiki/Stack_effect
Put the equation in a spreadsheet and you will see that the diameter has a much greater effect than the height on the draft\flowrate.