Welcome Swingpure! I've only been doing this a half a dozen years, and I never built a cinderblock arch. I did build my own arch (out of an old wood-burning stove), so I did learn one or two things the hard way. I'll answer your post point by point.
Originally Posted by
Swingpure
This is my first post. I am new to the maple syrup hobby/business and I am looking forward to this Spring when I can tap my first trees. I will start off tapping 16 trees on my property.
For your first year, depending on how much time you have to devote to it, that seems like a manageable number of taps. I'll get more into estimating boiling times later.
I plan to build a cinder block evaporator.. I will be poring a 6 concrete pad for it to sit on and will add sand on top of the pad. The pad is to help prevent any root fires as it will be built partially in a forest.
My side walls will be three and a half cinder blocks long and three cinder blocks high, plus a four inch solid block on top to ensure I have enough clearance from the bottom of my pans and the stove pipe.
That sounds reasonable to me so far, but maybe folks who do cinderblock arches can weigh in on how high the sides should be and what they should be made of.
I plan to have a 1/4 steel end wall that the stove pipe will come out of (the pipe hole centered about 15 off the ground). I will have cinder blocks behind it to help support it.
Seems to me you'd have more stability if you had the pipe coming off the top of a cinderblock, rather than out the back of an end-wall.
I also plan on having a removable 1/4 steel front wall, that has adjustable air intake holes near the bottom of the plate.
I wouldn't bother with adjustable air holes. You want a big opening that's open all the time. You need to have the same area of opening coming in as you have going out. So if you have a six inch stovepipe, that's 29 square inches. You need the same space for air in the front. If the arch is 20" wide, you will need at least 1 1/2 inches open along the whole width. Any less than that and you're starving the fire. Some folks add a blower to further increase the amount of air going to the fire, but you can get into that later if you decide to do that.
The goal is to also have steel to help protect the side walls. I forget the official name, but there are steel strapping that can attach to the side walls, that you can then attach your steel to, that will create an airspace between the steel and the blocks, hopefully helping to protect the cinder blocks. The steel would be 3 off the bottom and from the top to help create convection currents between the steel and the wall.
Your cinderblocks can tolerate the heat much better than steel. You do not want steel strapping in the fire, particularly if it's structural in any way. It will warp and fall apart. Anything in your arch made of metal (with the exception of the grate) needs to have the inside surface protected with insulation, and the outside surface exposed to air to help it cool. If it's in the middle of the arch, unprotected, with no air on the outside, it's going to get chewed up in no time. And the only reason why the grate can take it (sometimes - some people go through grates pretty quickly) is because it has cold outside air flowing up through it.
I will have 1 1/4 heavy duty steel grate sitting on some 3 bricks on the ground, to help with the air flow from the bottom.
Sounds good. Make sure your front "door" is set up so that all the air coming in is directed under the grate. Then have something that closes off the airflow on the far side of the grate, so the air can only take one path - up through your wood. Otherwise cold air will take the path of least resistance and go around the wood. That will cool down the inside of the arch and allow the fire to be starved for air. And as others said, the firebox - the part where the fire is (and the grate) should only be like 18 - 20 inches deep. So you only want wood from the front door, going back about 20 inches.
Up top I will have four stainless steel 20x13x6 pans, which should encompass the entire length of the evaporator.
Once you get this optimized, you should get on the order of one gallon per hour boiled off per square foot. So you've got about seven square feet. A good week mid-season may get you five or more gallons per tap. So that's eleven hours of boiling time. If you have that kind of time to put into boiling, you should be fine.
Am I looking for trouble using all of this steel, or is it a good thing? Any advice on any of this would be appreciated. I am still in the planning stages, but will be pouring my concrete pad likely next week. I have my pans, pails, lids, spigots already. The trees are already marked, as I have many other species of trees in my forest.
Thank you.
Yeah, all that steel is a mistake. Can you say more about what you're trying to accomplish with it? I'm sure we can help you figure out how to do what you're trying to do without the steel in the arch.
Also, figure out the inside of your firebox before you go any further. If you look around on here you can find examples other folks have given on how to make a "ramp" in your arch. If it were me I'd probably just add cinderblocks behind the grate, and fill in gaps with vermiculite or insulation or something. You're aiming for probably 1 1/2 inches between the bottom of the arch and the pans.
Have fun!
Gabe
2016: Homemade arch from old wood stove; 2 steam tray pans; 6 taps; 1.1 gal
2017: Same setup. 15 taps; 4.5 gal
2018: Same setup. Limited time. 12 taps and short season; 2.2 gal
2019: Very limited time. 7 taps and a short season; 1.8 gals
2020: New Mason 2x3 XL halfway through season; 9 taps 2 gals
2021: Same 2x3, 18 taps, 4.5 gals
2022: 23 taps, 5.9 gals
2023: 23 taps. Added AUF, 13.2 gals
2024: 17 taps, 5.3 gals
All on buckets