our first evaporator - an oil tank arch

[twin6]

This is our first evaporator, which began as a dream to cut costs and corners and make use of as much material on hand as we could. With youngsters involved, building from the ground up was important. We cut off an old heating oil tank, and welded in angle iron for the pan to sit in. The firebox grates are elements cut from an old cast iron radiator and the firebox door is a draft door off an old coal furnace. The flat bottomed pan is new s/s with 4 channels, with about 11 sq ft of surface. We used 1" durablanket which was not in use when I last bricked an arch over 20 years ago for a friend, and all I can say is it is worth every cent. Half bricks were dry laid in the firebox because it has been too cold for cement. Yesterday was the shakedown boil and all worked out fine. We started off with a light touch on the fire until we were satisfied we had no leaks, hot spots or other potential problems. I think this is going to work out fine, and the kids loved seeing the project, which began on paper and slowly came together just in the past 8 weeks, spring to life.

[twin6]

Just completed the third boil, and am getting a feel for the rig. We are at the expected 10 - 11 gph boil rate, with a nice even boil in 3 of the 4 channels. No doubt about it, cold sap has a quenching effect and the temps there run from 160F where the sap enters to 195F at the other end. We'll preheat next year, but our goal was to get this creation up and running this season, and improve upon it later. The insulation boosts efficiency and noticeably cuts down the appetite for wood. We've run a nice mix of soft (slab) and hard but fired less frequently than larger rigs that are uninsulated. You can put your hand 1" away from the arch and comfortably leave it there. Likewise, the stack is not blistering hot. The heat transfer to the pan instead of the great outdoors makes running this a delight.

[roastbeef]

Thats a great looking rig. I am going to try and make something very similar this off season. Who made your pan, or where'd you get it? And was it expensive? I've been running on a very small woodstove with a stainless serving tray this year. I only have 9 taps, but next year I'd really like to expand. Any information would be helpful. Thanks

[twin6]

A friend of a friend made the pan. There are very good sheet metal craftsmen out there who can make what you want, custom. I'm not sure I'd recommend going the route I did, because an oil tank is a mongrel size, not compatible with commercially made pans you'd be apt to find for sale new or used. We opted not to have a syrup pan, and instead focus on evaporating the best we could with a flat bottomed pan. We have a discarded gas stove that should do just fine for finishing, using a s/s stock pot. More control, and less risk to the pan. Poke around on this site, and you'll see some pretty clever DIY approaches to the common problems we all face.

[dustinanderson]

Very nice!!! Any idea where I could find that fire blanket stuff? I can't find firebrick for anything less than an arm or a leg around here either.

[twin6]

Google fiberfrax durablanket and see if there is a vendor near you. If not, get it shipped. It is not cheap, but it is an investment that will pay for itself over and over. Look at other threads on this site, and I think you'll find many are using 1/2 thickness firebrick, and minimizing the quantity so the brick's chief function is to protect the blanket in the firebox area. We just paid $1.98 per half brick at the local masonry supply.

[twin6]

Here's the post-season report. We had a very brief season - only about a week, but managed to boil 5 times and maintained a 10 gph boil rate without a preheater. The rig proved quite efficient, and did not eat wood like some smaller rigs I have fired. I give credit to the insulation, and smaller space for flames and gases to escape - both important for heat transfer and efficiency. Next year we'll preheat but we were running out of time to get the rig up and running just as the season started.

[dadtkm]

Hey Chopper, I to plan to build have tank, pan and a door plus a few other things. My question is would you share a few deminsions with me. Looks like the firebox is larger at the top than the bottom. Did you build a ramp from the firebox to the chimney end that sort of stuff.
Thanks, Tim

[twin6]

Firebox dimensions and setup - check the first post on this thread for a photo of the inside - the front and sides are plumb/vertical and the ramp is at a fairly aggressive angle to force heat to the pan. When you build a one-off, to a big extent the dimensions you end up with are determined by the components you have on hand. The radiator elements we used are about 7" by 24" and a standard oil tank has an inside width of 27" so we built in some angle iron rails parallel to the side walls. Firebox width after bricking was about 22", and from grates to pan about 17". The firebox in many commercial arches has sides wider at the top than the bottom. Never been sure whether this was in part to allow dry laying the firebrick and not worry about any toppling into the fire. I dry laid our brick because it was too cold for cement, and they stayed put just fine. If you can, avoid having the stack above the tank itself so you get more heat transfer in the space you have - build an outboard stack base. We went with an 8" stack which worked out fantastic. Get the ceramic blanket insulation and run it right out into the stack base (inside surfaces).

[whatever]

Hi chopper, what type of s.s. did you make the pan out of? I'm buildings pans this summer and was wondering the best thickness to use? thanks.

[twin6]

20 gauge. I'm told this is a nice midpoint, as thicker material does not transfer heat as well, and thinner becomes trickier to weld. I think the pans made by the manufacturers are 20 ga.

[whatever]

lol, a guy from work said 18 or 20 gauge as well, i had it in my mind that i needed 16 at least. i would have thought it wouldn't be stiff enough and that it would warp or twist easily when you handle the pan? I'll be making a flat pan without the baffles in it. are the baffles welded in so that it helps with support?

[twin6]

I'd recommend you take time to study what others on this site have made, and the reasons they went the way they did, before you commit to a particular design. It is a lot easier to correct design mistakes on paper. Our pan is welded and I think the baffles you refer to are the section or channel dividers that serve a greater purpose than simply to stiffen the pan. Look at post 7 and you'll see the gradient - raw sap starts at the front left corner, and after going down and back in the sections ends up at the front right corner at a higher temperature and with a higher sugar content. Think of the sections as alleys, with small ports at opposite ends - in our 5' pan, the sap travels 20' before coming off. The design is old, tried and true. The sections are wide enough to allow using a commercially made scoop and skimmer. A pan without dividers will limit you to making a single batch and you'll have to remove the pan and empty the whole batch. That's a challenge if you have a pan any bigger than a 2' by 2'. A good friend has that type of setup on his barrel arch. He likes the simplicity, but his options are limited. Others familiar with small rigs may chime in (and are most welcome to do so). The only time we lift our pan off after firing is to dump the last batch for the season. Those with larger rigs don't have that option and either chase the remains with water to push it through, or discard what's left. As you'd expect, there are advantages and disadvantages with small rigs and flat pans. And making your own rig brings not only challenges, but rewards. If you can visit some sugarhouses near you to see first hand what others have done, that should help you. If not, this site sure has some great threads that will help. Good luck with whatever you build!

[diesel79james]

I was looking for some pics of a 275 gallon oil tank arch's. I found some on this site that a father and son built and i think they were new yorkers if that helps ring anyones bell. I think the pics were in photobucket.

[rayi]

Where did you you get the door

[twin6]

The door came off a coal furnace (see first post in thread), and was probably a draft door. Salvaged many years ago by a friend in the plumbing and heating business who never found a use for it. He told me to bring him a quart of syrup and we'd be even, so trust me, I did. It is just "deep" enough that I could line it with the ceramic blanket (it stays in place without any fasteners) so the door never gets really hot.

[Twindadx2]

Looks good twin6. I am new to the site and have been digging around for similar ideas to improve from last year being our first. I like the oil tank idea and have young kids that loved to help last year. Cost is a factor, and would be living on my own in the woods if I thought on spending thousands on a setup. Keep us updated on this thread with pictures and design ideas for the oil tank arch!

[twin6]

5982

Getting fancy - hi heat paint is on now. Preheater coming soon.

[garyp]

looks great, just woundering how you hooked up your base stack any pics Very nice plans, thank you for sharing

[twin6]

59915992These aren't great photos, but they'll give you and idea of what we fabricated for an outboard smokebox or stack base. Making it big enough to insulate was the right choice - it really helps keep the exterior much cooler.

[garyp]

Thanks for the reply ,i see now that you went out the back ,you could make it deeper and go with a 6' pan if you wanted to ,
I have to get my pan first then i'll start building my arch around it, I'am going up to Bascom soon and take a look around,they seem to have some used ones that might work. Thanks again