Stack diameter on a 2x6

[RileySugarbush]

I am building a new arch for a 2x6 setup with forced draft. Stack height above the stack base will be 12 or 13 feet to clear the elevation of the cupola. Any suggestions on the best stack diameter for this situation?

[hard maple]

my 2x6 has 10" stack.

[ebourassa]

my 2x6 is aslo 10", but i have seen others that are 8".

[tapper]

The 2x6 that I had came stock from the factory with an 8" stack and it never lacked for draft.

[JasonS]

John,
I had a 10" stack on the arch that those pans were on. I believe that's standard.
jason

[RileySugarbush]

Thanks for the input.

[Russell Lampron]

Mine has an 8" stack and it is 17' tall including the base. It came with the 8" stack when it was new.

Russ

[maple flats]

The 2x6 I had came with a 7" and even that lacked nothing for draft. I had 16' of stack on it. It was an early 80's vintage Leader Pleasure model. Correction, I just remembered it was late 80's and had lo lead soldered pans.
Dave

[Father & Son]

My old Leader 2 x 6 has a 7" stack. Should I open it up to 8" to let it breath better?

[JasonS]

For what it's worth the new leader 2x6's have a 10" stack. They must have made a change for some reason.

[tapper]

Yaaaaa the change was to sell you the more expensive 10" stack. Mine was 8" dia. and 12 ft. high and never a problem with it and guys say a 7" worked also so sounds to me like 10" is overkill and more money gone out of your pocket.

[Teuchtar]

I have a 2 x 6 with additional 5' add-on. I put a 10" stack, 27 feet to the top. Works great for me. I'd say , don't skimp on the stack.

[802maple]

Draft will change with location and maybe one will find a 7 inch will work in one location and down the road at the neighbors a 10" isn't creating enough.

[The Sappy Steamer]

My new D&G came with the stack and cover. It's 10 inch as well.

[John Burton]

I went to the new leader stoe over columbus day weekend. and asked that same question . There awnser was the 10 in. stack was used on models with the new square sided arch to account for the added firebox.and that on my tapered arch like mine 8 in. is fine

[RileySugarbush]

What do you think there is about the squared off firebox would require more stack diameter? Does the new box have a back wall/baffle that extends up close to the syrup pan? Maybe that chokes of the flow a bit and necessitates added draft?

[tapper]

The squared off fireboxes are larger inside there is more cubic area that the stack has to pull from. Also with a larger square box there are more dead areas to try pull draft from. And I think most of the newer fireboxes are airtight which also would require a larger stack.

[RileySugarbush]

I ended up with a 8" diameter x 14' tall stack on this 2x6. I have more than enough draft, even with the squared off firebox. That's square sides and no slope on the back of the firebox. Forced draft helps I'm sure, but even with the cheap door I did not get too much ash flying out, so the stack had to be pulling about right. 30gph averaged over a day over the day with about 700 degrees at the stack base.

10" stack would have been a waste.

[parsissn]

I have the opposite problem, on my 2x6 with sloped firebox I get more draft than I want sometimes. I have 12' of 8" stack and more than once I've had flames shooting out the top of the stack. The arch walls and door are nice and cool so not too much fire there just such a strong draft it pulls it all the way through. Of course this is bad as it is wasted heat up the stack and not much transfer when the draft is that strong. As others have noted, it's all very situational.

[RileySugarbush]

I wonder if the flames out the stack mean too much draft or incomplete combustion? Do you have a draft fan on it? What is the temp at the stack base? I haven't run mine at night yet, so I don't know if I have an afterburner going or not. I don't think so, my exhaust is clean and the stack base at only 700 degrees or so when it's ripping along.

[Breezy Lane Sugarworks]

flame out the stack is incomplete combustion!!! there is too much wood for the amount of air in the firebox which chokes the fire, then the unburned gasses ignite when they hit the oxygen at the top of the stack. on my forced draft i have no smoke either. i run my stack 900+ degrees. I can get between 2.5 and 3 gallons of syrup/hr. (from start-up until the last draw) depending on the sugar content of raw sap. roughly 90-100gph(a few variables though...wood quality, firing intervals, firing amount, amount of air over/under fire, length of boil) 2.5x8 set of pans.

[WESTVIRGINIAMAPLER]

Ryan,

What size blower/cfm blower are you running on your evaporator and are you running it wide open??

[Breezy Lane Sugarworks]

it is a 10 9/16" diam. high pressure blower from grainger, w/ a 3/4 HP motor. the above fire air is wide open, and the under fire air is cut back a little.

[WESTVIRGINIAMAPLER]

How many cfm does it push and is it a Dayton??

[RileySugarbush]

Wow! That is 3 times the power of what I put on my 2x6, and mine is blowing lots of air, with a hot fire, clean exhaust, no ashes 750° stack base temp. Granted all my air is under the fire through the grate. I was thinking about diverting some of the air and injecting it into the top of the firebox, but had to hurry and get my arch done. I may try it next year.

[Breezy Lane Sugarworks]

grainger # 7D755, yes dayton. I have it set for roughly 400 or a little more cfm.

[rschoo]

I have a 14" x 71" flat pan and this year I changed the grates and the stack. The grates used to be cast iron out of an old charcoal grill and I had an opening 1-3/4" tall and the width of the fire box cut at the bottom of the door. My fire box is an old steel wood stove about 20" deep and 14" wide. I cut the bottom out of the fire box and made some grates out of 2" angle 1/4" thick. There are 5 14" pieces running sideways at the bottom of the fire box 3/4" or so apart with the points of the angle down so the v fills up with ash and keeps the angle from warping along with the cold air coming form underneath. I also went from a 6" stack to an 8" stack. My evaporator has never run so well and there is still some shiny galvanized coating on the bottom portion of the stack after 20 hours of boiling so it's not getting very hot. I increased my rate from about 7 gals an hour to about 11. There is 2" between the bottom of the pan and the fire brick in the back section. A 10" stack on a commercial made 2'x6' rig with flues doesn't seem large to me at all. In fact one would probably do pretty good with a 12" stack instead of a blower.

[WESTVIRGINIAMAPLER]

I am looking to upgrade the blower on my 2x8 Leader inferno and the 265 cfm Dayton 4c447 is not pushing enough air in my opinion. Just wanted some ideas of how much cfm I need and what size blower. Seems the Leader 2.5 x 8 drop flue infernos have a 4c054 which pushes 980 cfm.

[Fred Henderson]

Brandon, Stop fooling around with those little blowers and get a big squirrel cage out of a forced air home heating furance. Just block off what you don't need and run it with a 1/4 or 1/2 hp motor.

[802maple]

Brandon-
The blower that you have and the one that Leader puts in the 2.5 x 8 are basically furnace blowers that under restriction will not develop the cfm's that the blower being a high pressure unit that Ryan has in his arch. If you were to put his blower in your arch that thing would hop.

[WESTVIRGINIAMAPLER]

802,

Would going to a 700 or 800 cfm blower make the same difference or be too much??

What kind do you use in your intensofire arches you build and how many cfm would I need for a 2x8 arch??

[802maple]

Brandon
I use the same Dayton blower that Ryan did in his Dayton #7d755 it isn't only a coincidence that Ryan used that blower because I designed it for him. He is a very talented welder and wanted to build it himself. This blower would work good for you , it is alot more expensive than the one Leader puts in yours because of it being a high pressure blower and also it is lots louder so I recomend putting it outdoors for more than one reason besides the noise the best air you can feed your arch comes from outside as there is more oxygen in the outside air so you will get better combustion. The only thing you need to do is make sure hands or animals can't get in it because it shows no mercy.

[WESTVIRGINIAMAPLER]

802,

I have a 24 x 48 sugarhouse with an 8' additional for wood and with a 2x8 square in the middle of it. The only place outside I could put the blower would be up in the rafters on the 8' extension for the wood shed and then I would be piping air 30' up and down to get it to the evaporator, so I guess that option is likely out for me. Seems the guys like Tapper with the 2.5 x 8 Leader infernos are running a 980 cfm blower at 3/4 and getting 90 gph, so I guess I will have to look at something more along that line. One of the other members on here has the same and he said he was getting 115 gph with the same setup.

[802maple]

You certainly could get away with a blower like that for your evaporator as you don't have to get air thru the smaller passage ways that a Intens-O-fire has to for the top air. What ever you do will help in your production I am sure.

[WESTVIRGINIAMAPLER]

802,

Does the intens-o-fire have air nozzles above the fire under the syrup pan and if so, what keeps them from burning up?? All my air comes from underneath the grates and the arch front which has quite a few air holes and nozzles that get pressurized and force air into the fire as you are probably familiar with.

[802maple]

yes the intens-o-fire has front and rear air under the pans and they are 1/2 inch pipe, They are protected by ceramic blanket and held on by stainless bolts and washers There are about 24 in the door and under the front pan and about 20 under the flue pan in the rear of a 2 footer. This over air allows you to have a small fire with alot of heat. Generally in a 2 footer you would have only 6 or 8- 3 inch in diameter pieces of wood to a time.

[saphead]

802
I thinking about making my own 3x10 intense- o-fire type arch, I'm not sure how to calculate the pressure drop from the nozzles.I think a 600 cfm high pressure blower would be about right but I don't want to make an $expensive miscaculated guess.Any help from a seasoned design veteran would be appreciated. thanks,Craig.

[WESTVIRGINIAMAPLER]

So any more wood than 6 to 8 pieces is too much even in a 32" high arch with square sides??

[802maple]

Saphead-
Tell me what you have for a evaporator and I will give you the info needed.

West Virginia-
You shouldn't have anymore thah a half a fire box of wood as it chokes out the oxygen and you do not get a complete burn. Ryan is doing a easy 100 gallons a hour on his and he has a larger fire box than you do. He has about10 or twelve sticks at a time. Alot of sugarmakers out there that have that style of arch seem to think that filling the fire box to the hilt is the way to go. It might boil slightly harder but their chansaw's will run alot more this summer to pay for it to gain 4 or 5 gallons of evaporation more an hour.

Jerry

[802maple]

Sap head-
I guess I was blind, sent you a p.m.