New Homemade Arch

[Treetapper]

Starting my new arch tomorrow, but thought I should get some input from all the gifted minds on this great site. Its basically an angle iron framed arch that will be lined with 2 inch brick and skinned with galvanized sheet metal. Front will be 1/4 inch plate (because I have it) as well as both doors. Pans are just about complete (304 stainless), but will finish them once the arch is complete. I have my doubts I will use it for this year but I need to get this project out of the way. Too many more to come!

(The dotted retangles represent the fire brick placement inside the arch.) Some drawing lines don't show on converted drawing file.

Any thoughts are appreciated. See attached drawing.

Cheers

[vtsnowedin]

As I read your print your pans are both flat. If that is correct then you don't need ten inches under you back pan. four and one half inches woud give you one brick on its side down the sides and a layer flat plus an inch of sand would give you the right gap. Of course the ten inches is traditional and allows for a drop flue pan in the future with a rebricking but it means you build a space for the look of it just to fill it in to make it function properly.

[Treetapper]

The 10 inches under the pan was for a future drop flue pan, but I guess until I actually have one I should go with your recommendation with the 1 1/2 inch space under the sap pan. (Kinda forgot about that little detail). I can always lower the floor of the arch if and when necessary. Thanks for the good advice.

[Treetapper]

Made some changes to the drawing. Think this will do the trick? Any particular type of sand I should use? Should the gap be a little bigger at the fire box end compared to the stack end?:)

[morningstarfarm]

If I am reading the drawing correctly, and if it were mine, I would knock down that bottom space by about 10 inches..40 inches high before the pans..that's gonna put boiling sap right at face level..I dont want mine more than 24-28" tall to the rails. Pans can be up to 8-16" deep, and I want to see it all without getting that close. I would also leave the gap under the pan and fill with vermiculite and a piece of ceramic blanket insulation. Easier to build for expansion now than to redo it later. I'd also make sure there is something at the back of the firebox to protect a flu pan in the future..an errant piece of firewood can do a real number on a flu..just my .02 but in all it looks great

[vtsnowedin]

Made some changes to the drawing. Think this will do the trick? Any particular type of sand I should use? Should the gap be a little bigger at the fire box end compared to the stack end?:)

They use every thing from concrete sand to playground sand or ashes .or vermiculite. The good thing about it is you can add more or take out some until you find the right gap. Drop flues used to have a recommended gap below the bottom of the flues of just one half inch but others on here that have run flat pan rigs can advise you better on a starting point. As to the height of the main rails there is a choice to be made about how much bending you want to do when fireing vs. how easy it is to look down into the pans. It might come down to how tall you are. Some of the big rigs have the fire end of the sugar house stepped down a step or two to make the fireing easier but for a small rig that's not practical.

[Treetapper]

vtsnowedin and Morningstarfarm, Thanks for the advice.The top of my pans will be 50" off the floor. That puts them below my chest. I'm 6' 1" tall. I am trying to get the firing door up higher to save on my back and also to make easier to see where the wood is going. Hopefully to prevent hitting the pans! I figured if the pans end up being too high I can build a platform to stand on beside the evap. Ive seen commercial operations that have the entire set up off the floor and a sunk floor at the firing end. I know its probably a little on the high side for most, but I can easily cut it down a bit next year if necessary. I like the idea of filling in the deck with vermiculite to make way for a future drop flue pan. Will a ceramic blanket over vermiculite be all that is necessary or will it still need brick or sand over the deck as well?

[kinalfarm]

my pans are about 50'' to the top of them and i like it. not to much bending over to fire and i can see the pans just fine. make it to your saticfaction. only thing i was wondering when i looked at the plans is do you have a little bit of a ramp going from the fire box to the ramp? it didnt look like it and i would recomend it it helps the flu gasses and the flames head back instead of up and then back.

[vtsnowedin]

:rolleyes: Oh don't be getting started on that now. There are threads and threads about that and everybody has an opinion and nobody agrees about anything.
I looked around for arch board and couldn't find any locally and ceramic blanket cost more then my first born so I put mine back the way I found it with just bricks with sand on top and between the baffles. I'll try it that way and adjust from there. Even re brick if I decide that arch board or blanket under the bricks is worth it but I'm thinking that it worked pretty good for the first owner for thirty years so I may be all set.

[KenWP]

If you take your stack are and calculate it. Space under the pan dosn't have to be much more then that. Having a 8 inch stack with a area of 50 square inches. The area of the space under the flue pan shouldn't amount to much more then that. Basically works out to 1.6 inches for a 2.5 pan width. You can't go less then that as it will choke back your draft.

[kinalfarm]

well leader must be doing something wrong by putting a ramp in the firebox then. I figured they payed people to test that and thats why they do it. i guess i dont know much. forgett i said anything about the ramp.

[vtsnowedin]

well leader must be doing something wrong by putting a ramp in the firebox then. I figured they payed people to test that and thats why they do it. i guess i dont know much. forgett i said anything about the ramp.
Sorry Kinalfarm. You and I were typing at the same time and I'm a hunt and peck typist so your post got between mine and the one I was referring to. I've got nothing against ramps and wonder if all the small homemade rigs that come straight up are missing some potential boil.

[morningstarfarm]

Just finished building an arch very similar to yours, and it's gonna roar!..I'm getting right around 32 gals per hour without a preheater. The thing you're gonna find is that you're gonna need at least a 350cfm blower and I'd like to have even more. I did my deck 10" deep and filled with vermiculite and a layer of ceramic cloth..works the nuts and doesn't get hot enough to burn your hand underneath...had to think of blue laying there so he doesn't get cooked. I did ramp the deck but after filling it it's pretty much a 90degree now..I do have a drop flu pan and the gap is about 1/4-1/2 inch to force everything through it...good luck

[Treetapper]

I am fortunate enough to have a beast of a blower that is way older than me but works well. If I remember correctly its about 450 cfm. Its an old cast housing built in Galt, Ontario. Got it at a yard sale few years ago for 6 bucks. I ran back to the truck with that one! I tried it on my current arch last year. I had to choke off the blower intake due to too much ash etc.
This new arch will be air tight. Will try to post a pic of the blower tomorrow.

[Treetapper]

Picture of blower. Had to choke off the intake about 80% on my old arch, but it wasn't air tight so it was more for ash control. I plan on using it on new arch.

[Treetapper]

This is what I have so far. Its a project I had to put on hold for more pressing tasks. It should be completed by the end of the year. (2010) lol
Any comments good or bad would be appreciatted.

Cheers:D

[WESTVIRGINIAMAPLER]

Looks good!

[brookledge]

In the third picture there is cross pieces in what looks like area between the flue pan and the syrup pan. My question is why did you put that in there. Normally an arch only has side rails along with the front and back. I think you will find out that the intense heat will destroy those cross pieces. May be I'm wrong but I thought others may chime in to get their opinion before you get any further. Otherwise it looks good
Keith

[Sugarmaker]

Tree...
I agree with Brookledge, try the bar/s across the arch but they may start to sag after a few firings. I tried a similar idea to close off the gap between the pans and it melted and sagged after several firings. Mine was lose piece of 1/8 inch angle.
Other than that I think you are well on your way to having a very nice rig! This is going to provide you with much enjoyment. Keep the pictures coming as you progress.
I also agree that I would build the back of the arch deep for your future drop flues, and fill it with materials now for the flat pans.
Regards,
Chris

[3rdgen.maple]

I third the cross peice. It will not hold up and sag in due time. I would suggest cutting it out and use a pan gasket slipped between the flue pan and syrup pan to seal up that area. I have 3 flat peices of 1/8 inch steel that is slipped inside of pan gasket material so it does not drop in the arch. Works like a charm. Also noticed you put one in below the top one in front of the ramp. I would be concerned that one will warp as well and possibly pull the sides in a little. If it is there to protect the flues on a drop then cut it out and notch the bricks and let it float in there so it can be replaced as it warps beyond use. Other than that it is looking pretty good.

[Treetapper]

The cross rail between syrup pan and flue pan is to divide the two pans. This is the third evaporator I have used this type of cross rail on with no noticeable problems. However not with a blower. I didn't consider that. If it does prove to be a problem I will cut it out and use only the gasket material. Good idea!

[Treetapper]

The cross rail below the top cross rail dividing the two pans is actually to run brick up to that rail, then the ramp stars after that I know it sounds like kinda a radical design but it seems to help create some extra turbulence. I will probably have to lower this "wall" but I was thinking of trying it there first. Am I wasting my time doing this? My last evap. had a pretty hard boil in both pans although it was almost 2 feet shorter. (designed much the same)

[3rdgen.maple]

You will have to tell us when you fire it up. I really dont know how it would effect the boil. All I know is all the rigs I have ever seen just have the ramp and no wall in front of that.

[oxdrover7]

Looks real good.

[danno]

I had an old 30x8 that had two cross rails like yours - brick stood vertical into those rails to force the fire up into the flues. I know it was bigger than 1/8 angle - it was probably 1/4". Rails held up fine.

Now, I tried running steel tube in the fire box when building an air system - that did not hold up at all.

[Treetapper]

My last evap also had a couple of heavy angle iron cross rails between the two pans, no issues. but like i said earlier I didn't consider the extra heat created from forced draft. I will have to wait till after this season to try forced draft. It will be naturally aspirated this year. I actually did a test fire a few days ago to check for any leaks on new pans and overall performance. Found two leaks at the take off fitting, (the tig fixed that up). I had a big smile on my face when I went in for the night. The back pan didn't get to a hard boil but I was using a small amount of soft scrap wood for the test. Front pan was at a pretty good boil in about ten minutes. Will post some more pictures shortly.