My neighbor's setup is very basic. It is pretty much an unrestricted fire that you want to put out as much heat as possible to boil off the water as fast a possible. With the flat bottom boiling pan, the amount of heat transferred to the sap is rather low and a lot of heat goes up the chimney. The old setup using a homemade arch (two 55 gallon barrels) used a 8" stovepipe and the stovepipe got extremely hot. There was typically a 1.5' tall flame coming out of the top of the 16' chimney. There are a lot of fire proofing measures taken to keep from catching the building on fire. 
He doesn't have a way to monitor flue temps. However, he did have a stove top thermometer stuck on the stovepipe that would peg out past 900 degrees. We figured the temperatures were well over 1000 degrees.
The current (newer) setup with a real commercially produced hobby arch uses a 10" stovepipe. And the arch design pushes more heat into the pan due to the tapering of the back of the firebox to the stovepipe is a much better design than the homemade barrel setup. This reduces the stovepipe temperature some and the flame coming out of the stack is not nearly as common as it was with the old setup. There are still a lot of sparks as seen in my original picture above. This is all pretty standard for real backyard hobby operations. The fancy stainless contraptions like GeneralStarks are very expensive and the amount of taps it takes to feed them is more work than a hobbyist typically wants to put in. Whatever "efficiency" lost by burning a bunch of garbage softwood/crap hardwood in one of these hobby setups is acceptable to produce enough syrup for family and a few friends.
For next year my neighbor is getting a fancier hobby rig similar to this
.
The flue pan in this new rig, greatly increases the surface area of the pan exposed to the fire allowing a lot more heat to be transferred into the sap rather than letting it go up the pipe.
To follow up on the replacing of stovepipe above, the original 8" pipe was used for 3 years before going to the 10" pipe. It was still in pretty good shape. Keep in mind that this setup was only used for maybe 50-60 hours per year.
Last edited by From_the_NEK; 10-08-2014 at 09:44 PM.
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Aim for the chopping block. If you aim for the wood, you will have nothing. Aim past the wood, aim through the wood.</p>
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