I've got the bug, wanting to build an evaporator...

[l3rian]

I have about 10 acres of mostly silver maples. I put in 12 aluminum arrow shaft taps into 7 firehouse sub buckets over a few days. Ended up boiling 40 gallons into just over 3 quarts of syrup over an essentially open fire in a stainless steel bucket over 3 days. Learned a lot, but mostly that I could do it.

So now I'm wanting to build an evaporator to streamline the process. I've been thinking about the oil barrel as a start, but they seem to be hard to find around here (Iowa). My brother in- law has a metal fab shop with everything I could need, but it's 6 hours away, so I need a design pretty finalized before I head there for a few days.

I have a lot of basic questions on the design.

What thickness steel for the arch?

22 Guage seems to be what most pans are made of. Does it have to be "food grade"? Is there such a thing when you buy stainless sheets?

Any tips on the arch design? I get the basics, fire box in the front, ramp up to the chimney in the back. Roughly the same area at the back as the chimney.

I don't want to go crazy huge, but just want to be faster and more efficient with my wood than this year. Also, don't want to spend a ton of money.

Maybe I should move up to a barrel stove, but I like building things, I'm a decent welder, and can get the steel at cost.

I'm open to any suggestions or pointers. I really had zero idea what I was doing going in to this. I attached some pictures of my first try.

Thanks,
Brian

[tcross]

if you can weld, i recommend building one with angle iron. it's rather simple if you already have the ability and tools to weld. that's how i got started and used the rig for 6 years. some folks buy the pans first, or build them, and build the arch to fit the pans... some do it the reverse. search around on here a little bit and you will find plenty of pictures and diagrams that'll give you a good enough idea to build your own!

[Zucker Lager]

Building stuff is part of the hobby for most of us. Check this site Speedy Metals out of Milwaukee WI they have a discription of each type of stainless what it typically is used for and its merits.
https://www.speedymetals.com

Ditto Tcross I made my arch from angle iron I don't have a dimensional drawing but if your interested in ideas check out
http://mapletrader.com/community/showthread.php?26815-2-By-3-Hobby-Arch-Build
Jay

[maple flats]

Before you design an arch and the pan(s) I suggest you give us more info. Most hobbyists start small then grow. How many taps do you envision in 3 years, and then in 5 years? How many days did you collect this year to get the 40 gal of sap?
I think you likely want to build something in the 2x4' up to 2x6' pan size if you are thinking more than 50-75 taps. Any of those sizes can do you well. Then if you get too much sap, consider either making an RO (many plans available on this forum) or get a bucket RO, either complete or a kit. If fewer than 50 taps, a 2x3 should be OK, then a small RO.
An RO removes more water from the sap much faster and easier than burning more wood. The right small RO will remove enough water from the sap that you can then boil 50% less volume and many will remove even more than 50%.

[maple flats]

But, to answer the question, most arches are just angle iron welded frames covered with sheet metal (or SS) on the sides and also under it, except under the fire box. Most fireboxes are open underneath. The ashes fall thru the grates and are cleaned out periodically. Be sure to have enough air inlet under the grates for a real hot fire.

[l3rian]

Well, I think I solved part of my problem. I scored a pan on FB marketplace. Was advertised as stainless restaurant pan, 22"x44"x5". It's still in the vehicle (rocking my newborn daughter takes priority). I was planning a 2'x4'x6" pan in my head, so this is pretty dang close. It doesn't have a drain, I'll need to add that. Might be tricky since the bottom and corners are radiused. Now I just need to build an arch to fit it.

Here is a pic from the seller, I'll get more and verify the dimensions later.

Out of curiosity, what would a pan like this cost?

21458

[l3rian]

Before you design an arch and the pan(s) I suggest you give us more info. Most hobbyists start small then grow. How many taps do you envision in 3 years, and then in 5 years? How many days did you collect this year to get the 40 gal of sap?
I think you likely want to build something in the 2x4' up to 2x6' pan size if you are thinking more than 50-75 taps. Any of those sizes can do you well. Then if you get too much sap, consider either making an RO (many plans available on this forum) or get a bucket RO, either complete or a kit. If fewer than 50 taps, a 2x3 should be OK, then a small RO.
An RO removes more water from the sap much faster and easier than burning more wood. The right small RO will remove enough water from the sap that you can then boil 50% less volume and many will remove even more than 50%.

I'd say I collected sap for 3-4 days. I only really had time to do one batch this year. And time is really my enemy. I travel quite a bit for work from the end of January until the end of April most years with only a few weekends home. This year was an exception. I really think sap storage is going to be my biggest problem, which it's why I want the actual boiling to be much more efficient than a 5 gallon bucket. RO is very interesting also. I think it would help with the efficiency.

As for future growth, I'm not going go crazy. I got ust over 3 quarts this year. Ideally I'd like to make enough so I don't have to buy syrup and have some left over to share with friends and family. I just opened the last jar of what I made so I think I'd be happy with 3 or 4 gallons a year. Let's say 5 for a good target.

I know I have a lot to figure it still. Again, sap collection and storage I think are my big issues once I figure out the evaporator. Then I need to work on bottling.

[maple flats]

One issue with such a shallow pan is that a rapid boil will make sap jump out of the pan. That can be controlled by having an extension made out of ss to set on it. Design it so the geysers jumping hit the inside of the extension and run back into the pan. You want a fast boil, don't just slow the boil to minimize the jumping. Such an extension should be the outside dimension of the pan, then where it meets the pan, bend in 90 degrees, maybe an inch, then down an inch or so. I had my syrup pan (and flues pan) custom made 4" taller than std. The syrup pan is 14" tall to catch the jumping sap.