Bricking an arch

[Fred Henderson]

After leaving the fire box area how close should the brick be to the flues? The guy I bought from told me to have a min of an 1-1/2" clearance come under the rear of the flues where the flue drain is. There is that wedge shaped taper as you leave the fire box. I just put 1" ceramic blanket in first then 1" insulating brick. I still have the wedge shape with 1-3/4" of clearance near the back. Should I do more bricking near the front of the flue pan to raise the fire?

[Pete33Vt]

With my rig its fire bricked all along the sides of the rig, then we have the tapper going out of the fire box. This taper continues all the way up to the top of our arch. (the angle frame rails) Then it contiunes along the rail flush with the top. Till it gets about a foot /foot an a half from the stack. then tapers down sharply, so the heat can roll before going up the stack.That way all the heat from the fire box is directed up into our flue pan. But its a raised flue so it going to be different with drop flue.
Hope that helps.
Pete

[Fred Henderson]

Thanks Pete. I guess that I should have mentioned that I have a drop flue. I might have to see a pic of one. Anyone care to take a picture so I can see what I need to do.

[WESTVIRGINIAMAPLER]

Fred,

You can check out my pics on my website link below. :D

[Fred Henderson]

Thanks Brandon, Mine does not look like that so I guess its back to the drawing board or arch I should say.

[mountainvan]

Fred, If you put the ceramic blanket over the brick your rig will be more efficient. The ceramic does'nt draw heat like the brick, and it reflects the heat back up into the flue pan. New intensofires have just ceramic under the flue pan.

[Breezy Lane Sugarworks]

just keep in mind though, that the actual wood and coals can't touck the ceramic blanket. that still has to be brick. But I would definatly do what mountainvan said, and put the blanket everywhere else.

[Fred Henderson]

Well fellows here is what I did, I covered all the SS with 1" cermaic blanket top,sides, bottom back. Then I started with 1" fire brick in the ash area once I got on top of the grates I went with a full brick until the last 8 inches sides and back. The bottom I used 1" insulated fire brick. But my brick does not come very close to the flues like in Brandons pictures. When it was delivered, me and the builder were standing near the rear and he told me to have a min of 1 1/2" clearance under the flue pan. I had thought he was talking about the rear. I called a friend to see when I can go to look at his 3x10. It will not be to diffcult to add more brick. I have a lot of the light weigh insulating ones left.

[brookledge]

Whe I had a drop flue I had about 1/2"to 3/4' under my flues. just enough room for my drain pipe to clear.
You want to make sure that the fire and heat has to travel through the flues, otherwise you are losing btu's up the stack that are not coming in contact with the flue
Keith

[WESTVIRGINIAMAPLER]

The weight of the firebrick compress the blanket. Might want to try full size brick. :?

[Pete33Vt]

With a drop flue, or any flue pan for that matter the closer you get your brick, blanket or what ever, to the bottom of your flues the better off you will be. The whole idea is to get as much heat as possible to travel around and through the flues. So if you have a friend that could help set your pan on the rig and see what you got now. If you need to add you can. If you need to take away you can. Its better to do it now then when you have a tank ful of sap.
Pete

[Fred Henderson]

I agree with you Pete and that rebuild it going to start today. Rained all night and its going to rain all day. So its inside work for most of this week.

[mountainvan]

Fred, Leave enough room between the flue and the blanket for cleaning the flues with a brush. If the blankets too close it can get ripped up when cleaning the flues. Got that from experience.

[Fred Henderson]

VAn, Thanks for the heads up on the blanket.

[Jim Brown]

FRED: We had a dropped flue the first year we boiled. Our dealer told us to keep the brick just as close to the flues as we could. We used sand under the brick to make them 'give' just a little and we had the bricks touching or 'just about touching' all the way to the stack
worked for us. We now have raised flue and we have the bricks up to the angle side rails and the pan sitting on the bricks or'almost'.
Just a thought
Jim

[Fred Henderson]

Thanks to everyone. I worked on it this afternoon and I now have a 2" space from the flues to the brick. I know that the guy who built it said to have a min of 1-1/2" space and more would be ok. I feel now that I can adjust it with some sand as it needs it. I will put the flue pan back on tomorrow and see how it looks if its ok I will get everything looking pretty again.

[mapleguy]

Don't have much experience with drop flues, but with raised flues we always recommend 1/4 to 1/2 inch clearence between bricks and flues. The idea is to put as much heat through the flues as possible. Put some water in the machine and fire it up to see how it boils before the season starts. you should get a good boil in most of the flue pan, except where the cold water is coming in. It doesn't hurt to play around with the point where the bricks touch the flue pan. For adjustments use the ceramic blanket until you get it where it works best, then bricks for a permanent fix if you want.

[Fred Henderson]

I guess that I should also have mentioned that on this flue pan that the flues are not open at the stack end. The end of the flue pan extends down to an 1 1/2" below the flues and incoperates the flue drain. Therefore I can not have the bricks almost touching the flues, there would be no way for the stack to draw. By building it this way it must be to keep the flames from being pulled thru too fast and to give maxiumn use of the heat being generated.

[mapleguy]

Perhaps you could but the ridge of built up bricks 1.5 to 2.0 feet from the rearof the pan, then leavespace at the rear for the fire roll down to enter the stack. By not putting anything permanent at first you can play with the position of this ridge to see where you get the best boil and draft from your rig.

[Fred Henderson]

I plan on boiling some water on Sunday. I got it all put back together today. I am thinking that maybe the flues starting at the fire box should be real close to the blanket. This would force the fire into the flues and hold it in there until it gets near the back, then it could roll down and up the stack. Should be interesting. I will either make it work or junk it.

[mapleman3]

my blanket is only 1/4 to 1/2 " away and yes it does have an area at the rear so the flame will come back down to go up the flue, also I only give it about 2"depth for the flue, so the back of the pan to the vermiculite I have there is only a 2"space

[WESTVIRGINIAMAPLER]

Fred,

I think you have a drop flue don't you?? If so, it is totally different than some of these suggestions. It would need to be the same level under the flues all the way to back wall. :)

[Fred Henderson]

Brandon, You are correct and that is the way it will be, The builder said 1-1/2" or more. I will do a test boil tomorrow and see how it goes, then adjust from there.

[HanginAround]

I think I understand after re-reading some of it... it's a drop flue but not open across the back like a normal one, more like a raised flue in that respect where the gases have to come back down under the end of the pan?

[Fred Henderson]

HanginAround, Very good, you win a cookie and a maple one at that. That is exactly what it is and very well explained by you.

[Fred Henderson]

Well the test boil results are in. I sure hope that the guy that made the flue pan has a patent on it because it is totally awesum. I can see that a hood over both pans will ne needed. On this very damp day I was having trouble getting the steam out until I opened the back door. I boiled for about 1-1/2 hours and only succeeded in getting the stack up to 350 to 400 drg. I will tweek it a little more by adding some vermuilite to the bottom. I had the water jumping right out of the flue pan because it was boiling so hard. If the sap will do that I had better have some defoamer on hand. I was running it deep being careful the first time, maybe 2". How deep does everyone else run theirs? I guess its how brave you are!!!!!!!!!

[HanginAround]

Wow, sounds awesome. Glad it went well!

[Banjo]

Hey Fred,
great to hear that your evaporator seems to have been worth the wait (and associated frustrations) :D . I can't wait to see it when we get a chance to get that (now long overdue) road trip in.

cheers, Andrew

[Fred Henderson]

Hi Andy, Good to see that you are still hangin around this site. We will be waiting on that road trip.

[royalmaple]

Fred-


I envy your test boil. Still got probably another week or two before the sugar house is close to operational. Then I can go pick up my new 2.5x8 and set that up. It will be fun to get the steam rolling and see what she will do.

[mapleman3]

Fred a drop or two evry 5-7 minutes will keep it foam free.. do it everytime you add wood and you will keep a much more steady boil and sugar gradient. I keep a bit of defoamer(liquid) in a glass with a wooden stick about 8" and just hold the stick over the pan and drip off the stick, I used to use the bottle but found this to be easier ... oh and I use 100% canola oil worked awesome
just my 2 cents :wink:

[mountainvan]

I always have my back door open when boiling for the steam to go out the cupola. You may find that water boils harder in your evaporator than sap, it does in mine for some strange reason. I have my evaporator about 1/2" higher in the back than front, that way I notice the back of the flue pan is almost dry there is still syrup in the front pan and I don't have a disaster. I try to keep 3/4" in the back and 1 1/4" in the front. The level will vary some when firing or boiling really hot, 1200 degrees at the base stack. I normally have a stack temp of 800. Glad to hear it worked well.

[Fred Henderson]

Thanks for all the good advise guys. But I do not plan on running an 800 drg stack temp ever. I have heard about having the flue pan higher but have never tryed it.

[archangel_cpj]

Hey fred I am not a fan of covering the pan so you cant see so what I did on my smaller evap and what a friend did on his 3 x 12 was to build the usual cuppola and hood over the evap about 3 or so feet above the pan. then we went to home depot and bought two for mine and three for hes if those 19.00 dollar bathroom fans might be cheaper than that hooked them up in the hood blowing up and never looked back in fact we put a dimmer switch on them because we had a bit too much draft. easy hook up and of course use GFI

[WESTVIRGINIAMAPLER]

Fred,

If it is a drop flue, I would assume you would have to run both pans the same level unless yours is a new design. :? I run mine about 1" all the time. :)

[ibby458]

Great news about the boil. T'was well worth the wait!

[Fred Henderson]

Ibby, only time will tell.

[brookledge]

Fred
Start at 2" and boil for a few days to get the feel of drawing off then as you become familiar with it lower it down a little. Basicly you need to get a feel for it and learn how quickly your float responds to changes in levels. I think 1.5" would be a good level to work towards that way you move the sap along pretty good and still keep the level up to avoid burning.
Keith