Homemade Arch Dimensions

[MFarmall]

I am new to this site and have gotten a lot of good info to help with the 2x4 evaporator I am making. Wondering if there is a minimun or maximun dimension to have between the bottom of the flue pan and the insulation on the bottom of the arch. I am making a 2x2 flue pan with 4" drop flues and figuring on 2"-2 1/2" between the bottom of the flues and the insulation. Will have 1" insulation board with 1 layer of split fire brick on that. If need to I can change to a layer of full brick, to decrease clearance and help with heat retention, if I have to.
Will be using a door from an old wood stove on the front to seal better, with a blower running under the grates for forced air to the fire.
Thanks for any help, wish I had found this site sooner.
Hope to increase to 40 taps next year from 10 this year. Started late this year tapping but got 5 gallon of syrup made on steam table pan with propane.
Going to wood as propane cost going up and have 75 acres of woods to use for taps and fuel.
MFarmall

[Haynes Forest Products]

You want to force the heat up into the flues so you only want about 1" clearance from the bottom of the flues to the insulation. Things to consider are you have to match the size of the fire box to the flues to the stack side....its like a gas engine You cant run a big V8 motor on a chinsaw carb and then have it exhaust out a 2" muffler. With all the new types of insulation and fire brick its the fire that you produce more than how much of the heat you retain. With a 2X4 pans you dont need full fire brick in the drop flue area. With the amount of wood you can get off 75 acres I would think that one large fire box under the whole arch might work best and use the air intake to adjust the the boil. 75 acers with only 40 taps sounds like alot of pesky oak trees to burn have fun.

[MFarmall]

Thanks for the info. Since haven't formed the drop flues yet, will adjust the size to make them deeper (5"-5 1/2") to reduce the clearance between them and the brick. Figured on making a stack base that is 16"x4 1/2" to use at least a 7" stack, making it so if need to could go to 8" quick if need to.
Figuring 40 taps for next year, as between work and taking care of the farm (200 acres total) will see how time to boil works out.
Guess should have mentioned not all trash trees in the woods. Have 50 trees flagged in the front part and 45 in the back part. Been marking trees that are only 20" or bigger right now. looked at some more last week while pulling out some elm and ash for fire wood, if figure starting at 14" size counted another 50+ in front plus 42 of 4-8" diameter getting started. Hopefully in the next couple of years have time to get most of them tapped.
Again thanks for the info. Will let you know how things work.

[3% Solution]

Hi there,
If it was me I'd make those flues so they were about an inch off the bricks.
Make those flues 1/2" wide if you can, wish I had! Mine are 1" wide. It would just give you made surface area exposed to the fire.
As for the base stack, that would be just as wide as I could get it. This will help spread the fire out across the flues. If it's too narrow it will suck the fire right to the center and then only the center will boil hard.
If I may offer another suggestion, I would build a 2x3 flue pan and a 2x2 flat pan.
That's what I have and it works great!
Before I had the Evaporator Enhancement Unit made I was getting 17.5 GPH for an evaportion rate, now we are getting about 27 GPH.
Hope this helps!
Have fun and stay safe!

[MFarmall]

3% Solution, I am fabricating a forming die for the flues to make them 3/4" x 24" x 5" (changing from 4"), may try a piece of 18ga. cold rolled sheet to see how it will work with 1/2" width and 36" length.
I have been reading about some syrup pans warping, from thin material?, so have a couple pcs of 1/8" St Stl to use for the dividers on the syrup pan with the rest being 18 ga. St Stl. (20 ga and under gives fits to weld right all the time.) Normally smallest weld at work is 18 ga.
I have the arch frame welded up, need to start putting sheet metal on, have a pc of 3/16" th plate for the front, figure re-inforce a little and insulate good should hold up to the heat.

[3% Solution]

Good morning,
Yeah if you make those flues 1/2" wide I think you'll like that.
I think my pans are 24 guage (I think), had them for 7 years and they haven't warped yet.
I think the key to this that I keep sap in them when they're hot!!
I used arch board and 1" firebrick all around.
Remember,the more flues you have the more surface area you have in the fire. I have three in each section, 9 total, wish I had 18 total in there, but I don't and it still works well.
We have a four section cross flow flat (syrup) pan.
Hope this helps.
Stay safe!

Dave

[MFarmall]

Dave, sounds like your flue pan is about what I am planning, would have 3 sections, to make reversing easier, with 3 flues per section. Think could try for 4 per section with 5/8" to 1/2", have to see how crowded it would get for me welding on it.
As far as getting from the flue pan to the syrup pan, figuring running St. Stl. elbows (1" O.D./ .064 wall) out and connecting with high temp silcon tubing clamped. It has a heat rating to 350 degrees plus.
For now using metal have on hand and that can scrounge.
Also measured arch frame again, oops, can put 2ft syrup and a 33" flue and just get stack on. Guess learn from mistakes sometimes.

Mel

[3% Solution]

Good evening,
I don't reverse flow and it works fine.
About every 15 gallons I have to clean the syrup pan, builds sand and starts to burn if I go too long.
To connect from one pan to the other I used 3/4" copper pipe, elbows, unions, and a ball valve.
Soldered the unions to the pans so I can remove either pan.
The ball valve is to stop the mixing of the two pans after we stop boiling. Doing this you don't have to start over each time.
Go with three sections and 5 drops in each section. That thing will really boil.
If you send me a PM with your email address I'll send you some pics of my pans.
I'm waiting.

Dave

[MFarmall]

Dave, did some full scale layouts and could get (5) 5/8" wide flues in center, but till see pictures of your pans (hope got the PM with e-mail address) looks like might have to go 4 on each outer section till figure clearance to firebrick on the sides . Looks like will have to make a road trip up to northern part of the state to get a close look at some drop pans in a evaporator. Haven't located any our area yet.
Mel

[3% Solution]

Mel,
Should be in your email account.
I sent it out about 8 or 9 last night.
I can give you whatever dimensions you need, just give me a shout.
Let me know!

Dave

[MFarmall]

Thought would try and put a couple pictures of the arch I made on the site. Hope it works, kind of new at sending pictures to a web site.
It is 24" wide by 67" long, with a slight miscalculation. Will be making a 24"x24" syrup pan with 3 sections and a 24"x33" drop flue pan with 10 flues 4 3/4" deep. I am trying to get a better picture of the blower, but will put the best one have here.346

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348

[3% Solution]

Hey Mel,
Looks pretty good!!!!
Arch board and brick that baby and you'll be boiling sap big time!!!!

Dave

[MFarmall]

Thought try to get some pictures on here of the evaporator I built and some of the set-up I ended up with. Test boiled at 25 gph so figure with a little tweaking could push 28. It ended up being 24" wide by 58" long, the flue pan is 3 section with 4 flue each section. They are 5/8" wide by 5" deep, using a version of Johnny Cuervo's pre-heater.
Weather looks good for the end of this week if get through the next 24 hours, weather man is using term "gully washer" for the rain will get tomorrow with saying now winds that could hit 65+ mph.
Mel

[3% Solution]

Hey Mel,
Go for it!!!!!!!
Crank the baby!!!!!

Dave

[ElmDaleMaple2]

I need some plans and drawings for a new arch. I have a 2x6 and it needs a new arch. I have to make it myself so plans and drawings are needed! Thanks

[PARKER MAPLE]

im am also looking for a plan to build a drop flue. if anybody is willing to help please pm me the plans. greatly appriciated. thanks
im looking to build it at around 2x5ft with a 2x3 syrup pan. he arch is being built know with 1.25 angle steele. and 18 ga gal sheet metal. fire box will be around 2ft x 40in,when it starts ramping up. so how am i doing? any suggestions from the pros out there.... thanks for the imput