All Copper Evaporator?

[spason]

I have looked around on here, and can't find anyone talking about making an evaporator out of copper. I do other work with copper, and have a few sheets lying around- seems like it might be better than SS, and easier to fabricate.

Is there something I'm missing? Lead free solder, of course- anything wrong with this plan?

Thanks,
spason

[WESTVIRGINIAMAPLER]

Leader used to make copper pans and there are still some of then in use. I would think it would work great and boil way better than stainless pans. Go for it and keep us posted. Better keep it locked up to keep someone from stealing the pans.

[Homestead Maple]

When people started getting edgy about lead in solder and the possibility of copper being a contributer to heavy metals in syrup, manufacturers backed away from this. There was never anything proven that copper was aproblem. I have a friend that had a copper front pan on his evaporator at one time and he remarked as to how much better it boiled than a stainless pan and a lot of other people agreed. Some maple makers didn't like the color of the copper pans in the off season because they turned green but hey, a cleaning before the season took care of that very easily. I have copper tubes in a Steamaway that I have and there doesn't have to be as many tubes to do the same as one with stainless. I would have gone with copper pans throughout on my evaporator if I could have had it done at the time. The heat transfer is far better as you probably know.

[clafarr]

i have had a 4X4 front pan made of copper for years. That thing will take a beating. Too bad they are not available now.

[Mac_Muz]

Copper with no lead solder worked fine. I had the idea maybe you couldn't sell syrup made in copper these days. I think I can't in mild steel which I made for my pan.

I would have used copper if i could find any. Don't know how far you are from Tamworth NH, but if you need a guy with a metal brake, which wasn't here, when I made my pan there is one now.

There is a steel work bench here I did use to form the side upper edges rolled back to be double, for added strength, and a no cut and slash to the finger tips when lifting, and then to form the side walls, the other tool being a no bounce plastic mallet. The pan size to fit my barrel stove is apx 21" x 36" x 6", and to stiffen it I made two dividers.

In case you missed it I am begging for copper :D

[PARKER MAPLE]

i have one of leaders old drop flue copper pans, that i use. did a boil the other day in and plan on firing it up tomorow. this thing boils hard and gets there realy fast. know being new to all this i cant compare it to anything, but i know im very happy with it. if you want some pictures theres a coulple on my photobucket.a ny questions regarding it let me know, hope this helps

maple rookie

[killingworthmaple]

I have been wondering the same thing why not use copper? Please keep us posted if you make one, I am very interested on how it goes.

[KenWP]

Wonder what happens when you burn a copper pan. I can see a hole in it real quick. That and being soft it would wear fast from scrubbing.

[PARKER MAPLE]

the only complaint i have about my copper flue pan is trying to keep clean it up. i have noticed that clean up is a pain, the nitre seams to really adhear to copper moreso then stainless lots of scrubbing involved.. but it boils very good, on my test boil with water i thnk i was around the upper 40s in evaporation rate. with the firing really hopping. im sure i might be able to get it better if i had a preheater, and forced air.:o maybe next year

maple rookie :mrgreen:

[Haynes Forest Products]

Dont tell all the breweries that copper is hard to clean. What is the melting point and is it solid PURE copper? I use a pure copper bar as a heat sink and bridge for welding steel and it doesnt melt it.

[KenWP]

Thats because the heat moves away so fast. You have to get the whole peice hot and then watch it melt.Brass melts at 1832 degrees and copper is 1984 degrees. Iron is 2795 or a bit less depending on the source.

[Mac_Muz]

Ken, So far I have never burned a pan yet, so for me anyway that isn't a problem. I doubt cleaning a copper pan is any harder than anything else either really.

I clean my pan once a season and leave it dirty the rest of the year.

Today will be the day to power scuffy my pan, and make the inside bright.

I will hand sand the corners, and then wait till I have sap, probably coating the pan with 'Pam' as anti rust coating till then.

The day I am ready to run my first batch, I will fire the pan with water only to get the 'Pam' off, which it does well with hot water and elbow grease.

When the season is done I oil the pan with veggie oil right on top of the crud.

Then the stove is filled with the smoke stack, some of the tools, and the pan rests upside down on the stove till next year.

I could do the same with copper, and I would be using copper if I could get my greasy mitts on any large enough. I have smaller copper pieces to make candle lanterns of, but nothing close to make a same size pan as I need, so mild steel has to do.

[H. Walker]

At the end of the article there is a list of equipment and allowable materials that they can be made from for maple syrup production. www.mapaq.gouv.qc.ca/NR/rdonlyres/6702E67C-0626-4E75-8F22-FAD169BD5B21/0/Standardsonmapleequipment.pdf

[maplecrazy]

For you folks wanting to clean copper the best way is with vinegar and salt pour vinegar in and then sprinkle salt in it and let it sit for a few min slosh it around and it will be clean. I have been doing it for years

[Mac_Muz]

For you folks wanting to clean copper the best way is with vinegar and salt pour vinegar in and then sprinkle salt in it and let it sit for a few min slosh it around and it will be clean. I have been doing it for years

Thats right and I had forgotten. Other ways might be with salt water which cleans the stem brass up nice on my old wooden canou in the salty pond, and or even rotting oranges if you can get any.

Copper and acid from oranges and other citrus is TOXIC to people, so don't ingest the substance in anyway, but how I kbnow is at a primivite even a women who shall remain nameless here, made a fruit coctail dish in a large un-lined copper pan. The concocshun fizzeled in the copper by eye! turned green, and someone went crazy warning everyone. The good thing is no one ate any and that copper was some clean and bright for no elbow grease expended.

Vinigar is an acid, but I don't know what kind.

[TF Maple]

Standard vinager is 5% acetic acid. If I remember correctly, many insects have acetic acid in their stings too, causing the burning sensation.

[Mac_Muz]

Well I wouldn't know what insects have either, but the yellow jackets that got me last fall when I moved a rock back on the wall sure had some nasty chems to deliver into my hide. I sure wasn't pleased...

[PARKER MAPLE]

For you folks wanting to clean copper the best way is with vinegar and salt pour vinegar in and then sprinkle salt in it and let it sit for a few min slosh it around and it will be clean. I have been doing it for years

WOULD YOU DELUTE THE VINEGAR WITH WATER OR POUR IN STAIGHT. I HAVE A COPPER FLUE PAN THAT HOLDS LIKE 12-13 GALS SO FILLING IT WITH VINEGAR COULD GET PRICEY. WHATS THE RATIOS VINEGAR TO SALT?

MAPLE ROOKIE

[tylerj]

Would 24ga copper be too thin to make a pan with if its going to be soldered?? The piece I sourced could make me 2-2x3 pans with the front pan having 2 lateral dividers.

[RileySugarbush]

I'd be pretty careful with copper that thin. Get yourself a sheet and I think you will find it is not very strong or stiff.

Or check out this video:

http://www.youtube.com/watch?v=_TZX9b68wIw&feature=player_embedded

[03weim]

about 2 months ago there was someone in VT advertising copper pans with pictures on craigslist now I wish I saved the email address

[tylerj]

I am seriously thinking of ordering some copper to make one. After seeing that video RileySugarBush posted 24 gauge is definitely too thin. I'm looking at the 20oz copper now which is about 21 gauge which can be seen here:

http://www.finehomebuilding.com/how-to/departments/building-skills/soldering-copper-cap-window-flashing.aspx

I'm thinking it looks rigid enough for a 2x3 pan??

[WESTVIRGINIAMAPLER]

I don't think that is heavy gauge enough. I would think you would want at least 16 gauge or heavier. Copper is such a great conductor of heat, thickness won't be an issue.

[Housewright]

I am using pans I built with 16 oz. copper, 2X3 drop tube and 18"X24" partitioned syrup pan. They work great.

[RileySugarbush]

Housewright,

Really 16 oz like the sheet in my post earlier? .022 inches thick?

[tylerj]

Housewright,

Did you mean 16ga like westvirginia recommended or 16oz which is about 24 gauge??

[Housewright]

16 Oz.- 24 guage. The drop tubes stiffen the bottom of the sap pan, and the partitions do the same for the syrup pan. The top edges need a double bend or a roll to stiffen them.Lead free solder, make them deep-boil like thunder.

[TapME]

I like this idea. Easy to work with and would look great. Going to price out some sheet stock. I use to work and weld copper in a past life and it's easy. Now the cleaning part, what do you all use?

[RileySugarbush]

What did you use for your drop tubes? I'd love to see some photos.

[tylerj]

This was what I was thinking of doing for my copper flue pan design. These are 3/4" pipes I put on my s.s. sink pans I had planned to use this year.. and will if I can't make a new pan in time. It would sure be a whole lot easier doing it on copper than it was on s.s. ! lol

Housewright... how deep are your pans?? I've only been able to find 36" wide stock here in Canada so to make a 2' wide pan it would only be 6" deep which makes me a bit nervous. I would imagine these would boil over much easier than stainless.

[maple flats]

How will you clean in them?

[Housewright]

Tylerj
My drop tubes are set up similar to yours. There are more of them set up in rows and teed together. Each row ends with a tee and a threaded plug so they can be cleaned. The first row has a valve threaded from outside the evap. so the pan can be drained. Three foot sheet was what I had as well so the sap pan has a hemmed seam in each side. I made the sap pan 16" deep and still had to screen the top to control splashing (those drop tubes are like geysers). Once everything gets rolling they settle down.
Because of the 3' stock the sides of the syrup pan are 6" another 2" would be nice but works OK.
Heres a couple pics I can try to get others if you need, kind of hard to get the drop tubes since its all together. Maybe next boil, just finished one this morning.

[WESTVIRGINIAMAPLER]

How big is your all copper evaporator and how many gph do you get out of it??

[tylerj]

How will you clean in them?

Thats a good question lol. When I did it I thought those pipe brushes were more flexible than they are. Apparently they aren't meant to go through an elbow lol. The tee idea with a cap sounds like a plan though..

Housewright.. Looks good! What kind of evaporation rate do you get with that? Do you have 3 separate pans there?

[Housewright]

There is a third pan.I built the first two pans before the arch which then changed and got bigger. It was easier to add another pan than to rebuild.Seems to work well. Its 24" X52" and does about 20GPH. My biggest problem is getting enough sap ,seems just as eveything hits cruising speed its time to shut down. More plans for that next year.

[whalems]

Very nice looking rig!!:)

[jimbo752]

Im starting a flue pan now, and was really interested in using copper. I made some test pans out of copper and stainless to compare boiling rates. What i found was that the copper boiled a little better than comparable thickness stainless, but i ultimately decided that it was cheaper and easier to go with a little thinner stainless. 22 gauge stainless boiled just about the same as the equivalent of 20 gauge copper. This suprised me, but what i suspect is that as good of a conductor as copper is, it also acts kind of like a radiator up the sides of the pans, which takes away some of its efficiency. I think the ultimate would be a pan with a copper bottom and stainless sides, which could be done but a lot of work. The drop tube pans seem like they would do that nicely.

[tylerj]

That's interesting Jimbo about the comparison. The reason I am thinking of going copper is due to the easier fabrication.. easier bending of the metal and ability to solder it together. I don't have any welding experience let alone own a tig welder so I wouldn't even attempt a stainless steel pan.

I think the "radiator" effect you mentioned would really only come into play after the fire was put out. The sap in a copper pan would cool down quicker than in a stainless pan since the copper would suck the heat out from it faster. But if you have a constant heat source under it I don't think you are loosing any efficiency because you have way more heat coming in then you do going out. I think the difference is with a copper evaporator you get many more BTU's actually being used going into the copper, sap and radiating into the surrounding air from the copper compared to a stainless setup where if the stainless can't absorb all the heat those unused BTU's are going up the chimney stack. So I would think you'd get more bang for your buck, BTU-wise at least, with copper..... not to mention a much warmer sugarshack ;)

[PATheron]

One of the producers in out area has an older evaperator with all copper pans. I think the whole rig is 20' long Id say. Its pretty neat. Its oil fired. Theron

[3rdgen.maple]

Interesting but exacally how do you keep the pans from turning all green and crap? Petina I think is the word Im looking for. Seems to me if copper was the way to go wouldnt all the big evap companys be building them that way?

[WESTVIRGINIAMAPLER]

If everyone had an evaporator made out of copper, the evaporator companies would see a huge increase in their work force due to all the pan thefts. Stuff is $ 3 lb now scrap, so they would be stealing them left and right.

Also, the corrosion that copper develops is another reason they have went away from them.

[Bodine Mt. maple]

I have a 2 1/2 x 8 leader drop flue forced air all copper I don't have any problems with it turning green but it does tarnish. Before I bought it I called leader and talked to I think his name was Brad, at the time he had a copper rig and said price was why more people didn't have them.
As for evap rate we do 60-65 gph always and have done as high as 73 gph but that is really pushing things.

[TapME]

Priced out some sheet stock this week and here is what I got for prices.
Stainless 20 ga was $5 a pound and it weights 1.5# a square ft. The sheet I need is 4x5 so $150 for the sheet. This was for 302
The next one was 20ga copper that weights 1# a square foot and 7.60 a pound. The total price for this sheet was $152 a sheet.
The next question was would the state of Maine allow the use of copper and they frown on anything but stainless but will do not disallow the use of it or others as english tin.
The result is as said here before here the ease of working with the material would be the reason I would use it. Done a lot of fab work with copper over the years.

[tylerj]

Here is the response I received from OMAFRA here in Ontario;

Hello:

Thank you for contacting the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) Agricultural Information Contact Centre. We appreciate this opportunity to respond to your inquiry regarding the use of copper sheeting with maple syrup.

Here is the specialist reply:

A document on the Standards on Maple Equipment intended for the Production of Maple Syrup prepared in 2002 by the Manufacturers of Maple Sugaring Equipment (LMEA) in Quebec provides a list of acceptable materials to use in various pieces of sugaring equipment. 304 stainless steel is recommended for evaporator pan construction as you have mentioned. Copper is still acceptable for constructing sap pre-heaters and some connections but not for pans. Leader Evaporator company in Vermont has made copper pans in the past and some of these are likely still in use. There has been concern with the potential of increased copper levels due to the use of copper equipment and as a result the recommendation for stainless steel. I don’t think any tests etc have been done to check copper levels or the same concern expressed as for lead contamination. An electronic copy of the LMEA report is available if you would like it. You could also contact the Leader Evaporator company to see if they have any additional data on the use of copper in pan construction.

I hope this information is helpful. Please do not hesitate to contact us if you have more questions.

If you search the internet you see many references to unlined copper being used for carmelizing and other sugar based cooking. Copper reacts to acidic based foods. The common example is tomato sauce if you tried to make that in unlined copper the oxides would leach into it turning it a funny colour and giving it a terrible taste.

I would think the main reason they recommend not to use it is because there is no control of how well someone might keep their pans clear of corrosion. Obviously boiling in a flaking green copper pan would be an issue.

I have my sheet ready to be bend today. I have enough to make a 2x6 with divided syrup section for about $300 delivered.

[tylerj]

So I took the sheet over to a friends who had a siding brake. The sheet was 36x84" as I had a couple strips sheared off to be used for the dividers. I didn't want to attempt the 84" bend with a homemade brake. This is 20oz (20oz per square foot) or 21 gauge copper. I don't think I'd want to go thinner than this. The price I got for the 16oz sheet was only $30 cheaper than the 20oz. Once bent it was quite sturdy even with just the 2 long sides bent.

Then I took it home to bend the 24" sides with a home made brake I made out of 3 pieces of 24" angle iron. 2 are hinged together to form the bending part and a third on top and clamped down with a couple large "C" clamps. It really bent quite nicely.

So now I have a 2x6 pan ready to solder together. I have strips to divide the pan into 2x2 and 2x4 sections and also a couple more to make a 3 channel syrup pan. Since its only 6" deep I think I will extend the sides with aluminum - 3003 food grade is what I'm looking at - just to give it more height for a splash guard and boil over.

[tylerj]

The next one was 20ga copper that weights 1# a square foot and 7.60 a pound.

1# a square foot is actually about 24 gauge (0.216")

20oz copper is about 21 gauge (0.270")

[TapME]

" I don't think any test etc. have been done to check copper levels"

sure makes me feel real good if this is the information coming from the top level.. I guess I will have to stop drinking beer since the best is made in copper vats. lol

tylerj, just repeating what was described to me, the person runs a sheet metal shop I work with wood have to take there word for the price.

[tylerj]

No problem... I'd just hate for you to order something and it be not what you expected. There is a chart on this link showing the oz per foot/gauge/thickness.

http://www.copper.org/applications/architecture/arch_dhb/fundamentals/dimensions.html

[Dill]

I don't usually post craigslist links, but I have to say this in one of the nicest looking copper evaps I've seen.
http://burlington.craigslist.org/grd/2189034920.html

[poundcake]

I have a 2x6 all original drop flue Leader copper evaporator with internal float system. This was built in the early 1980's by Fred at the Leader factory. He told me cost was the reason they made such a low number of these. They were expensive to produce and harder to sell with the higher retail price. I have had this for five years, It has never turned green, and is very easy to clean. I love it. I have never burned a pan, I don't think it would be a good thing. Thanks

[Mjspear]

Where did you order copper from? I'm also going ahead with this. I'm planning 2x6 rig with wood gasification, combustion air , paper thin aluminum steam sap preheater. Thinking about raised and drop flues for rear pan. I priced some on line. It would be close to $1500

Mike

[Edson jones]

Copper works great ! We made a 2x9 rig with a 36 in evap pan and a used the stainless finishing pan . Our biggest boost was a 2x3 preheater with 8 24in drop flues we took a small 8 x 24 in section of the preheating pan to cross flow the cold sap and 1 divider down the center of the drop flues and got 40 degree sap up to 170.we made the 2 pans out of 16 oz copper because were oil fired and not putting wood in so no fear of hitting the flues.We also elevated the preheater pan about 10 inches above evaporator pan it seams to do well , last season our average evap rate was 50 -51 gallon an hour.Our pans might not look fresh from leader evaporator but they work really well and we really enjoyed making them. One more thing I learned when you put time and effort to make your own rig you will never taste any better maple syrup anywhere. Good luck my first pan looked like a 7th grade shop project but the second one looked like a strong 9th grade project.