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View Full Version : 2x4 evap ideas .... see pic and blueprint pics !



WoodButcher
01-20-2010, 02:19 PM
ok guys . ive got the bug !
last year i used an old steel barrel, cut 2/3rds of the top off and used that as a big cereal bowl to boil sap in . at 24" in diameter i was getting 2gph if i was lucky . that took a toll on me... but it was still fun .

now i NEED your opinons . :D :D remember now, i only have 20 taps this year. and if i need to upgrade next year i can sell this. . . but as of right now and for the next couple years i want to use this unit (a guy's famous last words :lol: )

i found a guy who can make me a 2x4 x6" high pan with a 1'x2' preheater on the back of it , all new SS and welded for 250-300$ . it sounds like a great deal .
he had some left over SS from a project he was working on. now, its 14 gauge though, so its thick. but i dont really care... its still gonna boil , and retain heat well... just wont come to a boil as quickly as others. . the way i see it, i would be using this flat pan as an evaporator pan , like a leader 'half pint' setup , so it needs to be durable since i will draw off a batch at a time and there will be a 30 second lag when theres nothing in the pan while its still has fire under it. just a thought......

now .
this is what i told him to put on the pan :

1. 2'x4' in size with 6" high sides ( or should i get a 2x3 pan? less sq ft but more in contact with the flames, right?
2. 2 handles on the skinny sides of the pan
3. a 3/4" nipple to thread on a ball valve (right size? )
4. 1'x2'x10"tall preheater pan (right size?) on top of the back end of the evap pan.
5. what kind of nipple should i put on the preheater pan ?
6. i can ask to put in dividers for my flat pan... but what good will that do ? do the divided sections connect to eachother? how do you draw off the other sections that are not by the draw off valve in the corner? remember , ill only have ONE pan to do it all .

thats it . i think those dimensions should be just fine, but wanted an opinion on the preheater pan size and the evap pan size.

heres a blueprint of member DAVYJONES's evap . he did a great job . also NEMO5 has the red model .

thanks for all the input !!!!! i just want to make sure i get the right pan made.

WoodButcher
01-20-2010, 02:25 PM
heres another last pic of the current plan and a few of my old setup to give you an idea where my motivation is coming from ..... heh heh :D

Ewetopia
01-20-2010, 03:09 PM
where will you heat up you pizza now??????????

RileySugarbush
01-20-2010, 05:02 PM
Even with a 2x4 flat pan there are advantages to to putting in dividers. They prevent mixing and allow you to run a continuous process. You don't need to run this as a batch process. Just keep feeding one end and drawing off the other as it finishes just like any other syrup pan. When you run low on sap, shut it down, cover it if you want and wait for more sap to start up again.

Even with heavy stainless pan, don't leave it on the fired arch without liquid in it. Even for a second. It will scorch instantly.

This will be a great rig for you.

peacemaker
01-20-2010, 05:10 PM
the pumpkin is funny

WoodButcher
01-20-2010, 05:21 PM
how are the holes made in the separators? just like little cut outs?? i didnt know if they needed to be certain specs. that pumpkin lasted all winter last year.. kind of creepy . :o

twofer
01-20-2010, 05:28 PM
I'm in the process of building an evaporator off Davy Jone's plans. In order to accomadate a 2x4 pan I shortened the chimney plate 4 inches and lengthed the entire arch 8 inches.

I'm pretty sure it will work but it's not done....yet.

C.Wilcox
01-20-2010, 05:35 PM
Riley hit it right on the head. I am doing the same thing as you, but didn't have dividers put in the pan and now I'm regretting it. Here's what I realized after buying my pan....with 20 taps you're going to get approx. 40 gallons of sap on a good day. That 40 gallons of sap will make 1 gallon of syrup, but you need at least 5 gallons of syrup to keep 1" of liquid in the pan at the end. To make 5 gallons of syrup you're going to need 200 gallons of sap and on a 2X4 that's 25 hours of boiling not to mention that you're going to need 5 solid days to generate that 200 gallons of sap. You could of course just shut down when you run out of sap, wait for more and then start boiling again. By the time you reach 5 gallons of syrup you'll have reboiled the same liquid 4-5 times. What I have decided to do with mine is one of two things, boil until I get enough to make a gallon or two of syrup, let the fire go out and transfer to a smaller pan to finish. Or, boil until I get a good amount of near syrup and store it until I have enough to dump it all back in the pan and finish boiling down to 5 gallons of syrup.

If you go with dividers, you can skip all of the ridiculous math and unproductive hours at work. There is a cut-out in the corner of one end of each divider so the sap flows through the pan like a maze. You pour fresh sap in at one end as you get it and pull syrup off at the other as it's generated. The only downside is you need to stay near the pan at all times or else you risk burning the syrup being made near the draw off port.

sugarnut
01-20-2010, 05:55 PM
from the way it looks, i have the same 2x3 pan and pre-heater pan that is pictured above. i bought it from a guy who makes them and sells them on ebay. anyhow, whoever said not to let it on the flame empty is absolutely right. it will scorch in a heartbeat.

i have been using mine on an outdoor masonry stove that has an old cast iron cookstove top. i remove the plates and sit my pan on a gasket. it sits sideways and i am only getting flame to hit half of the pan as it sits sideways. it does a fair job, but the boil rate is slow. i have lots of wasted heat. i tried draining the pan while it sat once...and it scorched right away. what i have done since it to let the sap boil down until it just covers the entire bottom, perhaps 1/4 of an inch deep or so, and then man-handle the pan off the flame and sit it on boards at such an angle to allow me to drain it. normally i boil for 8-15 hours (depending on how much sap i have)and refill the pan every couple of hours. i fill it about 2/3 full.

what i would do is to drain and leave just enough sap to cover the bottom and refill from the pre-heater pan.

i am still considering having some handles put on the pan and getting help to pull it off the heat. i don't plan to scorch that pan again...it was a pain to get clean again.

WoodButcher
01-20-2010, 05:57 PM
well this is what happened last year... the first day i had the spiles up , my buckets were overflowing, virgin trees ;) . thats 20 2.5 gal buckets = 50 gallons of sap . i pour the sap into brand new garbage cans that are sitting on the north side of the house away from any sun and the sides covered in snow. i can only boil maybe saturdays and sundays and one day during the week . sometime the sap sits outside covered in the cans for about 3-4 days. but its always clear, tastes fine, always checked for cloudiness. shoot, after a week there are huge icebergs in the garbage cans to keep em extra cool andyways.
so by the time im ready to boil from 7am all day on a weekend, i have atleast 50-100 gallons ready to go , and then whats being produced on the trees while im out there . i had to dump sap last year . that was mostly cu my 2 gph rig i had, but this at most is going to be 4 times faster, which is fine since i always have sap .
i digress . . . 8gph max would mean i can boil 48 gallons in 6 hours, and make one gallon of syrup in about 7 hours respectively . now i have to visit a local sugarbush operation to get a grasp on how to work these dividers .

how much can you draw off at a time? so my assumption is you put a thermometer on right next to the draw off spigot and then drain all the sap thats darker when it gets closer to 219 degrees and finish it inside? hmmm ... guess that would work .... would it be the whole last divider? or maybe half of it ? it would be about 2 gallons per section if im not mistaken at 1" deep

Haynes Forest Products
01-20-2010, 06:37 PM
As far as the dividers and how much you can draw off depends on the evap rate. The last divider is going to get mixed with the next divided section so you will want small draw offs. Smaller rigs with divider have higher density sap/syrup in most of the dividers.

kinalfarm
01-20-2010, 06:52 PM
i have had many thoughts on small rigs. I think you guys got the arch figured out but i would go with a 2x4 pan with two dividers in it, as for the pre heater pan put a 3/4 inch drain in that as well. the reasoning behind that is so you can buy a cheap brass float valve and a copper toilet bowl float and they are only about $30 for both and run the rig as a continuous flow evap. that is the only reason to put dividers in otherwise the sap just mixes together and they are pointless. also ad a cheap blower 80-150 cfm it will increase your evap rate by 20-30% and knock yer startup time down from an hour to about 15 min. hope my experience in this same battle heps you out. happy sugarin!:cool:

hey sugarnut just a suggestion but you said you fill yer pan 2/3 full. this is why you arent boiling so good. if you keepabout 2-3 inches in your pan at all times it will knock er time down because of the amount of energy the sap is taking to boil. make sense? any body agree?

farmall h
01-20-2010, 07:05 PM
Absolutely.

sugarnut
01-20-2010, 08:01 PM
hey sugarnut just a suggestion but you said you fill yer pan 2/3 full. this is why you arent boiling so good. if you keep about 2-3 inches in your pan at all times it will knock er time down because of the amount of energy the sap is taking to boil. make sense? any body agree?

your probably right, but without a float to feed in slow, there ain't no way i'm risking scorching this pan again, lol. some of the "need to feed" is also due to the lack of storage i have. last year i didn't even have my tubing up. the year before, i had a plastic drum (apple concentrate barrel) collecting from the tubing and i had tube from there to feed in slowly into my preheater. i let the preheater trickle in slow to match the boil rate and the feed from the barrel. last year i didn't use the barrel or tubing and i needed to dump sap into the pan and get the jugs back on the trees. one of these days i will be able to afford the whole package, lol. you know how it is. :D i could have used the barrel to store in, but i have it set horizontal on a fuel oil tank stand and it would have been a bit difficult to dump jugs and buckets into.

i know that once i get a setup where i can turn the pan longways, the boil rate will jump...i bet it doubles. i am thinking the current "sweet spot" is only about 2 feet wide and 1 foot deep. i plan to get that to be more like 20-22 inches wide and the full 3 feet of the pan.

Smitty
01-20-2010, 08:12 PM
Kinalfarm,
yes i agree, 2" is good. the sap in the pan should be at a good herd boil, but
you need to keep a closer eye on it, it can dry out in a hurry.



Woodbutcher,
use the thermometer, when it gets close to 219, open your draw off valve
just a little. Keep an eye on the thermometer, when it drops to 217, turn
draw off valve off. when the thermometer reaches 219 again, well repeat
the steps. once you do this a bit, you will be able to know exactly how
far to open draw off valve to keep it almost a consistant drip at 219.;)

WoodButcher
01-20-2010, 08:21 PM
ok , so what do you draw that into ? i mean your only going to take out a pint or so at a time, right?
do you just set it aside till you have a gallon or so, then put it in a big finishing pan (big pasta sauce pot for me) and THEN finish it?
in other words, do you wait for multiple draw offs then finish it somewhere else? i would think you have to since this separator pan is like an assemble line... always going . last year i just pulled the pan off the fire, dumped it in a pot, brought it inside, finished it (took about 20 min ) , filtered it, then reheated it back up to 185 degrees and bottled.

just would like to get a consensus

WESTVIRGINIAMAPLER
01-20-2010, 09:04 PM
With a small flat pan, you can boil the 40 gallons down to 5 gallons and pour it into a 5 gallon bucket and seal it up. Do it again the next day or two, whenver you boil. Once you do this 3 to 5 times, then dump the 5 gallon buckets of high concentrate back into the pan and boil it down to syrup. Done it before many years ago and works good.

vtsnowedin
01-20-2010, 09:06 PM
ok guys . ive got the bug !

1. 2'x4' in size with 6" high sides ( or should i get a 2x3 pan? less sq ft but more in contact with the flames, right?
2. 2 handles on the skinny sides of the pan
3. a 3/4" nipple to thread on a ball valve (right size? )
4. 1'x2'x10"tall preheater pan (right size?) on top of the back end of the evap pan.
5. what kind of nipple should i put on the preheater pan ?
6. i can ask to put in dividers for my flat pan... but what good will that do ? do the divided sections connect to eachother? how do you draw off the other sections that are not by the draw off valve in the corner? remember , ill only have ONE pan to do it all .

thats it . i think those dimensions should be just fine, but wanted an opinion on the preheater pan size and the evap pan size.

heres a blueprint of member DAVYJONES's evap . he did a great job . also NEMO5 has the red model .

thanks for all the input !!!!! i just want to make sure i get the right pan made.

1. Longer is better. There is a good reason commercial rigs are sixteen feet long. The fire is the hottest at the back side of the grates and it takes contact time and surface area for the colder sap to suck that heat from the flue gasses through the sheet metal of the pan. As for side height I'd go with ten inch sides cause you plan to get this baby really jumping.
2. NO handles. You might be tempted to use them with a pan full of hot syrup and spill it on yourself. Boiling hot bluejeans stuck to your thigh hurts like a sombrich.
3. 3/4 ? sure more then enough.
4. Sure but slant the bottom so that condensate runs to the edge and drops outside the pan so you don't have to reboil it.
5. Halley Barry's
6.Put in the dividers with plugs or slides to close them off when needed. Then you have in effect two three or four pans depending on the number of dividers. You close off the last section when it gets close to syrup and while its finishing you let in more sap to build up the level in the rest of the pan. When your syrup in the last section is done as far as your going to take it you open the draw off and as soon as the level gets low (not dry) open the plug or slide and let the new sap in. It will push out the last of the syrup and you can see the line between the syrup and the new sap by the difference in the bubbles. Shut off the draw off just as the new sap gets to the nipple.

PeddlerLakeSapper
01-21-2010, 12:42 PM
Sugarnut, here is what we did last year with a totally homemade pan. We put a divided front section that is 18" X 24" with a 3/4" coupler for a draw off.

The back section was just an undivided flat pan. Corners were clipped off to provide flow into and through the front section.

Preheater is about the same as you mentioned with a 1/2" feed line to the homemade float and float box.

Changes for this year will be the addition of 9 drop flues to the rear pan and dividers. The open rear pan caused the draw offs to be inconsistent time wise. We would be getting a couple of draws every 20 min., then we would go 40 to 45 before the next one. The rear dividers should eliminate the inconsistent draws.
The flow from the preheater needs to be restricted because the homemade float would not stop or slow down the flow enough. A valve should solve that.
Other than those things, this worked very well for a homemade pan.
This is also a heavy gauge pan. We were able to get about 15 gal. per hour out of it. Hoping for double with the 9 drop flue addition.

Haynes Forest Products
01-21-2010, 02:27 PM
Cool looking thermometer what make is it. Is your float lever twisted?

WoodButcher
01-21-2010, 06:39 PM
ok . heres an update . hes forming the 4x8 pan as i write this. .. a brake press that can handle up to 1/2" stainless ?!?! now thats angry ! :evil:
good thing my pans only 14 gauge .

anyways , heres the blueprints i sent him .
i want matching 1/2 threaded holes and a 1/4 NPT for a thermometer 3" away from the draw off holes.
also, i asked for the same holes on the opposite corner of the pan so then i can grab the preheater pan , flip it around and put it on the other side of the big pan and reverse the flow . badabing ! :D

i think the BEST cutout would be 2" away from where the divider is welded on the side wall , and be 3"x3" square . that way he can weld the ENTIRE end of the divider onto the sidewall . those TRIANGLES on the dividers pictured wont be very strong since theres only a little weld on the top holding it up .

i have so many requests im probably driving the welder nuts. heh .

PeddlerLakeSapper
01-22-2010, 09:07 AM
The thermometer was from Grainger. The float arm is flat with a bend on the front of it where the threaded rod attaches.

WoodButcher
01-24-2010, 10:21 AM
hes building my pan this week to the specs in my last post. i think i covered all the design ideas i need . :mrgreen:

WoodButcher
01-28-2010, 03:32 AM
progress......... :evil: just need to put in the threaded ports and done .

maplemaple2020
01-28-2010, 06:11 AM
im eventually going to make my own evaportor and i had the same idea and blueprints just my evaporator will be longer

Stickey
01-28-2010, 06:43 AM
Sweet pan. Miller lite time! Time for a Victory beer. :lol:

WoodButcher
01-28-2010, 04:30 PM
Stickey , your from NH .... Smuttynose pale ale for me please ! ! :mrgreen:

WoodButcher
01-30-2010, 06:17 AM
picking up pan today . 450$ out the door for 2'x4'x7" pan , 2 dividers (3 sections total), 2-1/2"draw offs on opposite corners, 2-1/4" npt holes for thermometers on opposite corners, 2 handles on big pan, 2 -1/2" stainless ball valves, 1'x2'x8" high preheater pan that slides from one end of evap pan to the other.

thats not too shabby . he says that when you lay the pan on a flat kitchen table, one of the corners will not lay perfectly flat. but i guess he said its so slight that if you put the weight of 2 textbooks on the corners itll flatten out. i guess thatll be ok right?
he said when he was welding the dividers on the pan's bottom it must have 'pulled' the pan a bit .
its going to be clamped on all 4 corners anyhow when on the arch .

leak tested and said everything is fine . not the shiniest pan from the pic but oh well .

BarrelBoiler
01-30-2010, 07:53 AM
it will propably lay down with sap in it - it may not
i would give it a test boil with water and see what putting heat to it does
our 24x33 two divider pan would go "boing" jusst about the time you didn't want to put your finger in the water. one corner always tweeked a little- used a ruler to check how deep the sap was to stay safe an find the high spots that needed to be covered
this is also a good way to get the hot water to clean the pan before the good stuff goes in

WoodButcher
01-30-2010, 09:45 AM
i just talked to him again for reinforcement and he said the pan corner has a slight lift , or dog ear to it . he said the bottom of the pan is perfectly flat.

in fact, when he flipped the pan over to check to see if the bottom is level, the dog ear flattened out on its own. i made sure he realized that the pan would be suspended on its own , aside from the 1.5" angle iron its resting on . he said the middle is totally fine.

again , its like laying a piece of paper on the table, and grabbing a small dog ear of a corner and lifting it up a tad.

i dont have time to test a boil in the parking lot im meeting him in . :-| so ill just have to check for quality of construction , welds, etc, and hope for the best. besides, anything funky can always be fixed with a welder and some mild fabrication . ....
im just a worry wart....:D

WESTVIRGINIAMAPLER
01-30-2010, 11:59 AM
Cut you some 1" strips of ceramic blanket and put it under the edge of the pan all around the outside. It will seal off the pan from ashes coming out, hold in more heat and will compensate for it being off a touch.

WoodButcher
01-30-2010, 03:33 PM
well, i got it :D

he did a good job . the entire thing is tig welded EXCEPT for the 2 dividers , which are mig welded.
you can tell because i think i could have made a smoother mig weld with stainless wire on the dividers. heheh. anyways, it lays perfectly flat, its totally fine. i pushed on it and it 'pops' flat, but if you lift a corner up it likes to bow up about 1/2" . .. nothing crazy. besides, 2" of sap covering a 2'x4' pan is just over 8 gallons .... thats about 65 pounds ... i think ill be ok ;) .

heres some pics... he did a great tig weld job on the small pan and the outer edges of the big pan. i guess if i wanted to make it pretty , i could have the local pro weld shop go over the mig welds on the dividers with a tig welder, reheat them, and smooth em out ... but i just want to get boiling !

thanks again guys for all the suggestions .

Stickey
01-30-2010, 06:35 PM
Stickey , your from NH .... Smuttynose pale ale for me please ! ! :mrgreen:

Make mine a smutty :D . I'll put one on Ice for you. Have fun boiling.

WoodButcher
02-07-2010, 01:04 AM
well i finished the outer framework for it. i did the 6 legs touching the ground, and made the framework around the pan (4 side pieces) . i decided to go with 1.5x1.5" angle iron to beef it up, and its 3/16" thick . i made it 36" high so i could make the firebox a little bigger.
that ended up not being the best idea because after it was all done, i didnt need the extra height in the firebox area. 24" tall firebox seemed too much .

now, for my front plate, what measurements should i use for :
1.distance from ground to ash pan floor
2.height of ash pan door
3. height of remaining fire chamber

so far, i have 10" from the ground is the start of the ash area , 6" high for the ash pan door, and 20" for a fire chamber.

i can play with these stats at will, so i was wondering what opinions everyone has on these.

finally, i have to decide whether to make the back wall of the fire box one firebrick high (4.5" tall), or lay 2 firebrick at 9" tall and start the arch angle from there to go back to the stove pipe.
if i start it at one brick high only , the ramp would start at 20.5" from the ground, and then would go to the back and attach to the back legs at 30" from the ground . that option is not too bad, BUT i know you want the heat as close to the pan as possible, thats why i was leaning towards making the back firebox wall at 9", then the ramp going to the back would start only 10" from the pan to the firebrick, BUT WOULD ONLY HAVE A RISE OF 4" TOTAL TO THE BACK LEGS.
does this make sense ? :lol:
its just that every arch i see seems like the ramps to the back rise atleast a foot higher of a difference from the front to the back . with 2 sideways firebricks high (9") option, ide only rise 4"-if i even want to- to the back of the arch.
now im rambling,time for sleep.... :mrgreen:

vtsnowedin
02-07-2010, 04:19 AM
No such thing as a firebox being to big. :) .The dimensions of that red model of NEMO5 should work as good as anything and better then most. Did you score some used cast doors or are you going to have to weld up some?

WoodButcher
02-07-2010, 09:55 AM
i couldnt find a door :( . im just going to use the remaining burnoff rectangles from cutting the openings for the loading door and the ash door.

now i know theres going to be about 1/4" gap between the loading door or ash door from the 24x26x3/8" thick plate ill be using for the front. the 1/4" gap is from the torch burning off a nibble of steel .
the only thing i could think of to combat this was take some 3/16" flat stock laying around and weld it to the inside edges of the loading door frame and ash door frame.... BUT hang it over the lip just a bit so that when the loading door closes, itll rest onto the flat stock. then ill stick some insulation or stove door rope onto the flat stock sticking out so it can close softly and seals as good as it gets. what you think? only thing i could think of

vtsnowedin
02-07-2010, 02:10 PM
Too bad your not closer to VT. I'm sure I have one in the scrap pile that would do. What you plan will work but the insulating rope needs a groove to set in. Better to leave it out unless you plan on a super blower system. When you are cutting the door holes out are you going to free hand it or clamp on an angle iron to guide the torch on?
edit.
I just hoed out that door. It's a cast door to a homewood funace 15" wx14"h has the gasket in the groove and the flop latch with spiral handle all on it. You can have it for the postage or UPS charge.

WoodButcher
02-07-2010, 02:15 PM
i plan on either clamping angle iron to it for a guide, OR just having them cut both holes to spec. im sure it would be only like 10$ more. well see.

vtsnowedin
02-07-2010, 03:02 PM
i plan on either clamping angle iron to it for a guide, OR just having them cut both holes to spec. im sure it would be only like 10$ more. well see.
Check out my edit below. We were both typing at the same time.

WoodButcher
02-07-2010, 03:26 PM
pm sent...

Grizz747
02-07-2010, 06:08 PM
Tractor supply in chardon had barrel kits for about 35 bucks earlier in the year. Nice cast door.

birdmancf
02-07-2010, 06:31 PM
Hey Woodbutcher,

I'm in the same situation designing the arch. I think that I read comments about Davy Jones' design and how others had raised the ramp to close down the space between the firebricks and the bottom of the pans. I'm heading in that direction with the dimensions of the firebricks determining the final heightof the back wall, I figure less cutting of bricks the better. As far as it needing to ramp, I don't even consider that a necessity, the right draft will pull the flames and heat in any direction, even down. Right now my only problem is that I am having someone else fabricate this, so I can't do any building on the fly. I have to have it all planned out. I may not get 'er done 'til after this season:(

WoodButcher
02-07-2010, 06:31 PM
Tractor supply in chardon had barrel kits for about 35 bucks earlier in the year. Nice cast door.

heres the link to it . hopefully they have them in the store. ill look at them tomorrow. besides, i need the flue collar too but i dont think it will work because the base gasket has a curve to it to accommodate a barrel, not a flat surface. it be real nice if it is in stock so i can see it.

http://www.tractorsupply.com/home-improvement/heating/wood-coal-heaters-accessories/wood-heaters/united-states-stove-co-barrel-stove-kit-3192628

WoodButcher
02-07-2010, 08:10 PM
heres a nice one .
i found a seller with this door for 55$ shipped .
its a vogelzang door from one of their wood stoves.
18"wx10"h would be nice, as well as the glass ! :lol: am i getting too fancy now? its just i know i loved it when i changed my wood burning insert's door in my house from having a steel plate on the door to having glass. it was like night and day since you just needed to look in the window to check on the fire . not too bad a price for a cast iron door with a window. though i would lose some heat from the glass allowing it through, but i dont think it would be too too much

Big_Eddy
02-08-2010, 08:27 AM
Anyone else wondering if a glass insert in a door will stand the temperatures in an arch. Usually a lot higher than in a normal woodstove. Thoughts?

Ewetopia
02-08-2010, 10:12 AM
if the glass is ceramic it will stand the heat. i have a wood fireplace with a ceramic glass door and burn it like a gasification unit to maximize the heat. you will need some way to keep the glass clean. it will be black in no time unless you wash freash incoming air over it to keep the smoke off

WoodButcher
02-08-2010, 04:22 PM
well i do have a bit of info on this. ive been burning wood for many years and can tell you this : if you choke down a fire's air supply from below or above, your gonna get a sooty window, no matter what . unless you have a new high tech epa stove which uses an 'air wash' system to push cool air from above and into the firebox and the onto the glass.
anyways, were not talking about epa stoves here, and the LAST thing we wanna do is smolder an arch fire !!!:o if my wood burning insert has dirty glass from banking the fire all night so itll last till ill i get up, all i do is load her up and open that ash door for about 20 minutes while it catches and BAM , clean glass :mrgreen: . also , i used to have a coal stove with glass in the door . one time i accidentally hit 1300 degrees by leaving the ash door open and passed out on the couch! glass was fine and stove went back to normal . . .

i digress .....

i dont think the glass will dirty up seeing how ide be running at 400+ degrees all the time. i have oodles of sugar maple, hickory and oak all seasoned 2+ yrs... ill be good .
but i think i just might keep it simple and get that cast iron door. besides, cant wait for it to be finished. dang impulse buys...:mad:

WoodButcher
02-08-2010, 09:13 PM
frame update..... tomorrow im gonna set the diagonal ramp angles . not welded in yet .

Old County Road
02-10-2010, 12:28 PM
Thanks for sharing your progress Woodbutcher - I'm learning a lot. On your pan construction - it looks like only the corners (and the dividers) had to be welded. Is that correct? Did the welder make cuts and then bend the pan sides up? Looks that way but thought I better ask to be sure.

Thanks again!

WoodButcher
02-10-2010, 02:57 PM
it looks like only the corners (and the dividers) had to be welded. Is that correct?

glad i could be a help!
in regards to the pan , with the brake press used, we could only bend 3 corners, and one of the skinny 2' sides needed to be tig welded on the bottom and sides to the rest of the pan. the corners obviously were tig'ed .the dividers were the only thing mig welded with SS wire. it was too hard to get in there and tig em . wish i did though, the SS mig wire was messy , but that was the welder's fault :o

ive been solely going off the plans from davey jones , but making improvements as i go . ive been talking to him asking what he would change, and the only things he said were lengthening the space behind the pan so he can sit a stock pot of sap on it, and making the angle of the arch that goes to the back be less of an angle.
i didnt care for putting sap back there, as my preheater pan is about 10 gallons and on top of the boiling pan so ill be ok .....
as for the angle of the arch, i DID change . how i changed it from Dave's plan was make the 2 diagonal angle iron pieces that connect to the firebox 9" above where the grate rests, or 2 brick-heights high (2 laying on their sides =9" )
this way ill only need one brick or 2 at most going back to the stack. no need to heat up area thats not by the pan .
also , this will allow me to stuff up the firebox more and not have to lay wood on the arch going back . youll see when its done. i bought only full brick, but i might return some if it gets too cramped.. i think itll be fine though .

i made the firebox 24"w x 24"l x 18.5" high . the ash door is 6" and the ash pan to the ground is about 10. total of 36"
ill have more pics on the way !

WoodButcher
02-10-2010, 05:10 PM
UPDATE:

i found a metal dealer that has 4x10 sheets of mild steel in 16 gauge and 18 gauge .

i am going to pick up the 16 gauge just cus its only 10$ more a sq ft (2$ a sq ft ) than 18 .plus, im not using any wool insulation or whatever, just full brick. the shop doesnt have galvanized, but thats ok with me .

anyways, i drew up a grid of a 4x10 sheet , and made boxes, each representing a foot. i was seeing how much sheet metal i really needed , and i noticed on Dave's plan the firebox side sheet is separate from the arch's side sheet, and i wanted to try to get them together. my overall height was 27" from top of angle iron surrounding my pan to the bottom of the ash door. i have my angle iron turned up so it cradles the box... didnt want to knock over hot sap. i just had to grind out half circles for the NPT ports.
the overall length for mine is 66" , which is 2' of firebox, 2' under the pan after the firebox , and another 1.5' for the pipe and whatnot.

the sheet will be 4x10 . . i will have them use the shear and cut it at exactly 66", or 5'6" . that leaves me with just over a 4' x 4' piece for the rest.
that would include the arch ramp (2'w x 3.5' long), small piece in the back capping off the arch (roughly 2'wide x 8" tall) , the bottom of the ash pan (24"x24" square) and the small piece in the back of the firebox (roughly 24" wide x9" high)
think i need to pick up some shears !!! :mrgreen:

vtsnowedin
02-13-2010, 09:08 AM
UPDATE:

i found a metal dealer that has 4x10 sheets of mild steel in 16 gauge and 18 gauge .

i am going to pick up the 16 gauge just cus its only 10$ more a sq ft (2$ a sq ft ) than 18 .plus, im not using any wool insulation or whatever, just full brick. the shop doesnt have galvanized, but thats ok with me .

anyways, i drew up a grid of a 4x10 sheet , and made boxes, each representing a foot. i was seeing how much sheet metal i really needed , and i noticed on Dave's plan the firebox side sheet is separate from the arch's side sheet, and i wanted to try to get them together. my overall height was 27" from top of angle iron surrounding my pan to the bottom of the ash door. i have my angle iron turned up so it cradles the box... didnt want to knock over hot sap. i just had to gring out half circles for the NPT ports.
the overall length for mine is 66" , which is 2' of firebox, 2' under the pan after the firebox , and another 1.5' for the pipe and whatnot.

the sheet will be 4x10 . . i will have them use the shear and cut it at exactly 66", or 5'6" . that leaves me with just over a 4' x 4' piece for the rest.
that would include the arch ramp (2'w x 3.5' long), small piece in the back capping off the arch (roughly 2'wide x 8" tall) , the bottom of the ash pan (24"x24" square) and the small piece in the back of the firebox (roughly 24" wide x9" high)
think i need to pick up some shears !!! :mrgreen:
How are you planning to attach the side sheet metal to the angle iron?
On a commercial rig the side angle are turned down and rivets or bolts go through the down leg and through the sheet metal that is tucked up inside it. The front sticks up an inch or so as does the stack casting which keeps the pans from moving front to back but they are free to expand side to side on the smooth surface of the angle iron or on the gasket if you use one. Also the bottom of mine is one sheet of sheet metal that starts at the back of the grates and goes up the ramp then level back to the back casting then up about four inches and bolts to the inside of the back casting.
16 gauge and shears won't go together very well. Even 20 gauge is a tough go for hand tools. A diamond blade in a angle grinder will do the job but don't forget to wear your saftey goggles every cut.

WoodButcher
02-13-2010, 10:36 AM
i just got a pair of 110v power shears, and theyre good up to 14 gauge mild steel and 16 gauge stainless. theyll do the job just fine .

as for the sheet metal and attaching it ...
i flushed up most of my angle so that i will 1/8" diameter 1/2" long metal rivets (NOT aluminum) through the sheet and through the angle, im thinking every 5" or so on the frame.
i dont need to raise my sheet to accommodate the pan because i turned my angle iron on the top (first weld i made on the project) so it cradles the pan, but i left 1/4" of play for expansion. ide rather trust angle to hold that 80 lb pan full of sap in place than sheet.
but yes, just rivet it up and i think itll be ok .

here are some more rough pics after welding up old hinges laying around for the ash pan trap door. didnt want to make it air tight as i want a draft coming up through the door as i am not planning a blower unit on it this year. the hinges stay open at any angle i like , which is nice for draft control... but who knows if theyll flap the door back down when heat is applied to the firebox! .
i like the cast iron door. pretty beefy but nothing spectacular. it DOES have a draft control right below the door which is an added bonus for me :D
i didnt put all the bolts in the loading door yet, i just wanted to mount it up to see how it looked. also , i havent smoothed out the edges of the holes cut for the loading door and ash door.
one other thing i changed with leader's idea and some other was with my grate . i didnt like how the Leader grates were resting on the frame's angle iron only at the 4 tips of the flat iron use to make up the grate. in other words, the angle iron that makes up the grates is just floating there suspended, with only the 2 strips of 1/4" flat iron holding them in from falling . with my grate i made the angle iron that makes up the grate go all the way to the inside edge of the frame (minus 3/8" for expansion) so then all the heated stress of 300-700 degrees will be on all members in the grate.
the only thing that stinks about this is that now i will have to rest my first firebricks on the angle iron from the grates. ij tested it though and they easily balance, but well see when its all full !

P.S.
what does everyone think of filling the upturned angle iron used on the fire grate with refractory cement? i read a couple people did this with their grates so that the angle stays insulated so it wont warp or time. i know ash will naturally insulate it , which is why we turn the angle with the point down in the first place. leader makes their grates this way.

vtsnowedin
02-13-2010, 09:54 PM
i just got a pair of 110v power shears, and theyre good up to 14 gauge mild steel and 16 gauge stainless. theyll do the job just fine .

.
Oh going Tim the Tool man on us. MORE POWER Ha Ha Ha.
Best of luck with your project.

WoodButcher
02-13-2010, 10:01 PM
well they were only 45$ at harbor freight(eck), but built like a ton of bricks. was going to get the 30$ pneumatic ones that hook to your compressor, but they were only good for 18 gauge or less. im sure they would work on 16ga, but hey , for 20$ more, ill cut through it like butter. :evil:

RileySugarbush
02-13-2010, 10:11 PM
My arch was build much like Davy Jones' and I skinned it over with 16ga. A nice alternative to rivets is self tapping sheet metal screws. The drill right through the sheet metal and the 1/8" angle. Easy, strong and removable if needed.

WoodButcher
02-13-2010, 10:17 PM
ill have to check them out . thanks! how do they hold up in heat?
though my angle is 3/16" thick . theres somethin about rivets that are a nice clean look .

RileySugarbush
02-13-2010, 10:56 PM
They are steel and hold up well. Also the flanged hex heads look fine. You can find them at a hardware store of on McMaster.com part number 90064A480

http://www.mcmaster.com/#90064a480/=5t4571

They can drill themselves through but with 3/16 angle you may want to pilot drill with a small bit to make it go easier and faster.

WoodButcher
02-16-2010, 08:27 PM
heres a couple more pics finishing up the frame and pipe collar.
sheet metal step is this weekend as well as firebrick placement. then a test boil . ill take a bunch of pics here with a real camera, this is just my phone ..

WoodButcher
02-21-2010, 05:33 PM
ok , all the finish welding is done . painted the front with high temp paint, and popped in the door i got at tractor supply.

the only thing i need to do now is rivet the sheet metal sides on . i just laid the arch on its side, lined up the 16 gauge sheet and traced the arch sides.

i also need to get about 45 more firebrick (about 90 total) .
im overdoing it with full brick lining the ash pan. (shocking... i know) , but a full brick brings the edge of the brick parallel with the ash pan door, so i can just sweep the ashes into a pan easily.

i cored out some holes in the angle iron to accommodate for the thermometer and draw off valves. so i put a brace of angle iron under where i made the cut... just to keep it as strong as it was before i cut holes in the angle.
my measurements as to where to put the angle iron were carefully selected so that i could use as much firebrick as possible , without cutting.

i got a husky diamond 7" blade for 15$ at home depot for my circular saw , and a 4.5" husky diamond for my angle grinder for 7$. they work great so far! just put a fan on em and wear earplugs, glasses, and a mask if you are gonna use a fan . more pics soon .

WoodButcher
02-22-2010, 09:54 PM
got the big sheet metal sides on tonight. used 3/16" thick rivets instead of 1/8" thick . man this thing is like a battleship !!! i used 110v power shears from harbor freight for 45$ . the box said they would cut up to 14 gauge sheet metal, and the lower moveable jaw broke within 18" on my 16 gauge :mad: . shocking. thanks harbor freight for this chinese crap .
anyways, went there today , got a pneumatic auto body saw with a blade like a sawzall just shorter... that thing just went in about 1/2" and was bouncing around everywhere. im returning that.

THEN i bought a pneumatic air shears like the first ones but powered by an air compressor instead of 110v. they worked better with my small 5 gallon 3hp compressor. i ended up getting sick of waiting for the compressor to fill up between cuts so i got out the angle grinder with 2 cut off blades and shazaam :D .

anyways , heres some pics. i need to rivet in the bottom of the ash pan and the bottom of the arch angling back , and a couple small back plates and im done .
just need to brick it. i need to weld on an axle on the bad boy to wheel it around ! its heavy .
i hope someone is enjoying these pictures and getting ideas from them .....i know how pics on here have inspired me to do several things in my garage !

WoodButcher
02-22-2010, 09:56 PM
heres a couple more ....

Big_Eddy
02-23-2010, 07:15 AM
i hope someone is enjoying these pictures and getting ideas from them .....i know how pics on here have inspired me to do several things in my garage !

Keep the pictures coming. We're loving them.

WoodButcher
02-24-2010, 07:23 PM
all done . ready for a test boil . found a great local place by me that will custom make your 1/2" stainless pipe to size. im having them make a 90 degree knuckle for the preheat pan, and for the draw i still need to decide, but im assuming ill go 6" out from the pan, 90 deg elbow down, and then 12" down to drip into my big tomale pot with the paper and orlon filter ready to go .
i lined the ash pan with full firebrick . i know its overkill but i like how i can rake the ashes out and the brick is level with the ash door so they fall right out into my dust pan .

the stack is 9' tall.
firebrick line the whole firebox and rest on the framework of the grate . i liked this approach because so many people complained about their grates sinking and warping i decided to run my grate the whole 24" width of the firebox. that way every angle iron slit is resting on the sides- east to west. i then put a 1/4" thick flat iron on all sides so the brick can rest solidly . the bricks are locked into place to by the top ange iron made for the pan to sit in . you can pull on the brick but the edge of the upper angle iron catches them so im good to go!
you can also see how i overlapped the firebrick thats going up the back of the firebox and meeting up with the brick laying on the angled arch . that way no angle iron is showing .

WoodButcher
02-24-2010, 07:24 PM
heres a few more. ...

WoodButcher
02-24-2010, 07:26 PM
last bunch ....

farmall h
02-24-2010, 07:28 PM
Nice Woodbutcher. Big door...like that! Ready to test fire?

WoodButcher
02-24-2010, 07:31 PM
thanks. ya , its ready to go . ran out of daylight so i couldnt tonight. want to check in daylight so i can look for smoke leaks, warpage etc. im sure ill be ok , but ide rather appreciate it in the light . cant till sunday , ill be out of town all weekend :mad: oh well . ... delayed satisfaction ..:lol:

still need to think of a solution to label the cut bricks. i was thinking maybe use my dremel tool to make a number on the bricks.. i dunno

Treetapper
02-24-2010, 10:01 PM
Nice job. That will put a smile on your face.

oakstreetsugarhouse
02-26-2010, 08:49 PM
Dude, Nice work! Want to make me one? About how much did you spend on materials? Thanks! I need a real arch for my pans. I'm tired of setting up the cinder block arch.

WoodButcher
02-27-2010, 04:02 PM
Well it cost 450 for the pans to be built with stainless drawoffs included. Good score there ..... about 80 feet of 3/16 angle, loading door, front 1/4in thick fascia,90 bricks, stove pipe, etc..... . it weighs about 250lbs without bricks. Not too bad considering I gained a lot of knowledge doing it . Its also gonna last me many years...or at least till I upgrade. Hehehh...

WoodButcher
03-07-2010, 12:48 PM
did my first boil off last night. was up until 4am . started boiling at 6 . boiled about 50 gallons. worked great . i did find 2 pinhole leaks in the separators , one in each separator.
though when i was washing out the pan before i boiled in it . the water droplet takes about 2-3 seconds to form and then it drizzled into the other divider area. ill seal it up in the summer... am hoping its not that big of a deal. if it is , i can do it this week .

anyways , the pan was perfectly level when boiling , though- as you can see from the pics- im on a steep hill and it took about 2 hours to level the thing! :mad:
anyways, the sap level was slightly off , as it was higher in the rear underneath the preheater by about 1/4" of an inch or so .
it boiled great, really needed to feed it maple and hickory though , i think its due to the 16 gauge thickness . the middle divider and first divider on the left (sap entry) boiled the hardest, whereas the last syrup divider was that slight nickel-sized-bubbles . i got worried about that , thinking it was my pan not fully seated on the right side or something . ill investigate today .

anyways, i think i screwed up .
someone told me to push along the sap from time to time while boiling to aid in getting the sap through the dividers... well i think i did too much :rolleyes:
after 6 hours of boiling , the thermometer didnt change from 211 degrees the whole time, and the middle dividers was about the same color as the syrup divider!!!
i have to admit.... i was kind of making a wave with my ladel pushing the sap around like a little kid . .. probably didnt help the physics of things eh??

now im fretting its the 2 tiny pihole leaks... but i severely doubt it.
anyways, it goto too late last night , and all i had was about 4 gallons of tan stuff throughout the every divider but right under the preheater spout... so i called it a night , closed the draft and waited till it was not simmering anymore.

i also think my draft is wayyyyyyy too strong. the flames were touching the pipe way in the back. with the ash pan door almost closed, it helped a little bit.
also , it seemed like the flames didnt hit the evap pan until halfway back . im gonna put the damper that came with the barrel door in so i can control it more... though the damper is 6" and my stove pipe is 8", at least itll slow it down somewhat.
the point here is to make sure most of my heat stays under the pan as long as possible, without letting all the heat go up the chimney . no smoldering , just making sure the heat doesnt exit too fast out of the smoke chamber. ive been heating my houses over the years with pure wood heat for many years, so i am familiar with the phenomenon.

SO , IN RETROSPECT..

arch design = A+
pan design= A
aid from this forum = A++
The WoodButcher used to batch syrup making and switching to a divider pan = D-

WoodButcher
03-07-2010, 12:57 PM
heres more.... the last pic of the tshirt was just a design i made for a local maple syrup contest coming up in a month . at my sugarbush , there are a million squirrels ,and they seem to take a liking to my sap buckets... so just for a joke i took some clipart and made a shirt . :lol: i dont think ill print it out and wear it to the contest though ! :lol:

Brookmaple
03-07-2010, 07:59 PM
Woodbutcher, where did you get your fire brick and how much did you pay/piece for it?

WoodButcher
03-07-2010, 09:13 PM
a local place called r.w. sidley . huge company that supplies aggregates , masonry block products, structural and architectural precast components, and building supplies. pretty cool place. looks like an atom bomb went off when you get there... with all the huge mounds and machines... :D
got them for 1.45 each for full brick. not too bad .

reboiled the left overs from yesterday , got a gallon off . tastes great . light-medium amber.

Brookmaple
03-08-2010, 07:47 PM
Woodbutcher,

That's an excellent price for firebrick. I can't find anything north of the border in Canada for under $2.25 for 1.25". Go figure even Hamilton, the refractory capital of Canada can't even come close to your price. Have looked far and wide for something used or reclaimed to no avail.

Your syrup looks good--enjoy!

vtsnowedin
03-09-2010, 05:45 AM
Nice finish to your project. Ten hours for fifty gallons with eight sq. feet of boiling surface is right on the standard rate so you have it set up pretty well. Next comes some fine tuning with wood and fireing and your preheater etc. but you'll never see seven gallons per hour. While you sit in your armchair sipping your cherry juice you can draw up the plans for the sugar house/ tool shed your going to set about where the Christmas's tree is now.:)

WoodButcher
03-09-2010, 06:42 AM
draw up the plans for the sugar house/ tool shed your going to set about where the Christmas's tree is now.:)

ya... that would be nice to have. but as of right now, i like being outside... as long as you have good company... or a wireless laptop :D .

i was talking to a few locals and i didnt know you need to feed this thing a piece of wood every 4-8 minutes! i was treating it like a wood burning stove in a home and maybe load it every 20 min or so .

so im gonna try to hit that 8gph mark !


bought a pan gasket kit. little 1"x1" ceramic strip. ill use that to level off the pan so its not 3/16" lower in the back. going to boil tonight, and THIS TIME im not gonna try playing with the sap in the pan like a kid in a sandbox ! :lol:

just gonna let physics do its thing.... see what happens .

PeddlerLakeSapper
03-09-2010, 09:05 AM
Here is a pic of our 2X4 that is doing 20gph this year. Last year it was a flat pan doing 10gph. We cut the bottom out of the rear section and added 8 flues 5 1/2"s deep. Also, for this year we added air over the fire. Internal stack temp run between 700 and 800 degrees. Loading 4 or 5 wrist size pieces of wood every 15 minutes.

PeddlerLakeSapper
03-09-2010, 09:09 AM
Oops, first pic was too big.

SColum
03-09-2010, 05:11 PM
Woodbutcher,

That's an excellent price for firebrick. I can't find anything north of the border in Canada for under $2.25 for 1.25". Go figure even Hamilton, the refractory capital of Canada can't even come close to your price. Have looked far and wide for something used or reclaimed to no avail.

Your syrup looks good--enjoy!

Try Atkinson Maple syrup supply. Its 1.99 for 2" firebricks.

vtsnowedin
03-09-2010, 06:20 PM
Here is a pic of our 2X4 that is doing 20gph this year. Last year it was a flat pan doing 10gph. We cut the bottom out of the rear section and added 8 flues 5 1/2"s deep. Also, for this year we added air over the fire. Internal stack temp run between 700 and 800 degrees. Loading 4 or 5 wrist size pieces of wood every 15 minutes.

How long are your flues? I can't resist doing the math but I need all the pertinent dimensions.

maple marc
03-09-2010, 10:47 PM
Dave,
I'm interested in hearing more about how you are getting 20 gph on your 2x4. With my Leader WSE 2x4 and plenty of draw we get about 18 gph. Wonder if it would be worth it to tweak mine.

Marc

WoodButcher
03-14-2010, 03:29 PM
rigs running great . grinded down the 6 or so firebrick that was on the top edges of the firebox so that the heat could hit more of the edges of the pan. helped a lot .

installed a 8" damper in the stack . i know most info on this site says more draft the better, but sometimes you can have too much draft , and the heat leaves the stack too fast. besides , i got it to toy with . im glad i did ! i played with it all day , tested it from the handle being 12 oclock(wide open) all the way to almost 9 o clock ( closed ) . after tons of testing in the 8" stack , i found the temperature cruised nicely at about 10 o clock . it seemed to boil more in the dividers on the outside of the pan , and the wood lasted much longer. i only put in 4-5 wrist pieces every 15 minutes or so . rode at 700-800 all day . in fact at one time the needle on the rutland thermometer snapped right off the base from hitting over 850 door temp . :o . dried hickory ... cant beat it .

its sad but im already thinking about extending the 2x4 arch for next year! maybe welding on another 2 feet to the back , sliding the divider pan back and welding up a 2x2 flat syrup pan for the front above the firebox . what ya think ?? :D
i was thinking of raising the rear 2x4 sap pan an inch or so cus then the ready 'sweet' can flow into the syrup finish pan in the front better.... does that make any sense ?
the reason for this is i realllllyyy want to finish on my rig and not use a turkey fryer to finish on when the last divider hits 215 degrees. the only way i see i can do it is take 50 gallons, boil it down to 5 gallons , draw off the sweet, throw it in a bucket and save it . then in a few more days when i get 50 more gallons of sap, do the same thing. so then ill have 10 gallons of 'sweet' to boil off and then there will be enough concentration and depth in the pan to actually chase ready syrup to the draw off.

as of right now , 5 gallons will cover the entire 2x4 pan 1" deep . it seems like theres just never enough ready sweet after a 10 hour - 70 gallon boil to make the thermometer get past 213-214 on the draw off end. im doing everything right .... allowing warm sap to drip in constantly to initiate the push of the sweet. who knows...

anyone have any comments/suggestions? thanks! :mrgreen:

WoodButcher
12-02-2010, 08:21 AM
im getting the itch to start fabricating something .... :evil:

PeddlerLakeSapper
12-03-2010, 01:28 PM
Flues are 28"s long. Also added a steam pre-heater and was running this 2x4 up to 29gph.

WoodButcher
12-03-2010, 05:41 PM
Flues are 28"s long. Also added a steam pre-heater and was running this 2x4 up to 29gph.

i dont know in regards to what your replying to , but i like the GPH on a 2x4 !
boy i wish i had that. only getting about 8 gpm .

i want this pan i attached below so bad .. .it would pop right in my arch and i can just sell me current 2x4 pan for a few hundred .
its on ebay , but its 1100$ shipped. TOO MUCH for me :o .
would make life easier though . . .

maybe i can just put a finishing section in my evap pan ??? why not? in other words, my evap pan would be 2' wide x 3 1/2' long . and make a divider in the front over the firebox thats 2' wide by 6" long . . . think i might have problems with gravity draining the sweet into this front finish pan . . .

look how nice this pan is though ......... save up my pennies ! :rolleyes:

whalems
12-03-2010, 05:55 PM
That looks like one of patrick phaneuf's pans. You should have plenty of time to save money. If you ordered today you could expect delivery by 2014!:lol::o

vtsnowedin
12-03-2010, 11:52 PM
Flues are 28"s long. Also added a steam pre-heater and was running this 2x4 up to 29gph.

Sorry it took so long to get back to you but other work takes my time between sugarin seasons.
Now lets see. ...
8 flues with 5 1/2 inch sides 28 inches long. We can ignore the end caps and the bottoms came from the bottom of the 2 ft X4 ft pan so you gain 16 X 5.5 inches x28 inches = 2464 inches square /144 sq in. / sq. ft = 17.11 ft sq. plus the original 2 ft.x4ft.= 8 sq. ft gives a total of 25.11 sq. ft. Call it 25.
My old 1964 Leader book states that it takes 50 sq. ft. of heated surface to boil 32 gallons of sap per hour. That would give you a base of 16 per hour. A blower may give you 10% improved efficiency and take you to 17.6 and a good hood and preheater another 20% to 25% depending on who you believe. That could get you to 22 gallons per hour. So if your getting 20 per hour it's not your imagination. You have a well set up rig and some very good wood.
May this years sap be 3% and buckets full.