Looking for Firebox help

[nhdog]

Several years ago, I took part of my woodshed and turned it into a 10'x15' sugarhouse. I used 2 modified wood stoves and finished the syrup on a propane burner.

I now have a 220 gal tank (60"x24") and have finished welding it up to hold 3 full size steam pans.

My plan for the firebox is 20" deep, 17" wide, 16" from the grates to the bottom of the first two pans. The flue will be about 2.5" deep under the 3rd pan and runs to the 6"x12' stack, which is about a foot beyond the 3rd pan. I'm thinking this will work for the firebox.

Any comments or suggestions before I weld up the frame and do the brickwork?
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[hookhill]

How about sloping the back of the firebox so that the flames can shoot up to that last pan.

[barnbc76]

Do you have covers to put in place where the pans go fir when you start consolidating near the end? I would parobably make the fire box as large as you can, I think mine is like 24" deep. Also if you can get a fan it makes a lot of difference in evaporation rate. If possible consider building it in a way so you can expand, maybe a 2x3 pan. Others would probably suggest a ceramic blanket insulation or fireproof foam board. Where did you find the glass for your door?

[johnallin]

Any comments or suggestions before I weld up the frame and do the brickwork?
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It looks pretty darn close to the wall in the back there...you will need some protection on that wall if you don't move the rig out further.

[buckeye gold]

I agree with the others suggestions. The two things I think you should address is how close that thing is to an OSB wall. I would line that firebox with ceramic blanket and then brick over it. I also wonder if the pans should not be farther back. I will wager that first pan won't boil very well, draft naturally wants to pull your heat backwards towards the flue. You have room to set them back.

[nhdog]

Thanks for all your inputs.
First of all, I have a metal heat shield running up behind the arch and stack. I took it down temporarily while putting the stack up.
Yup, I have 3 covers to cover the openings when i remove the pans.
I got the glass from an old wood stove. Then I made a door to fit it and the arch.
I plan to insulate the box and add AUF through the draft/ash cleanout door under the grates.
Yeah, I agree that front pan probably won't boil too well as it is now.
A couple more questions:
Is it more effective to extend the firebox partially under the third pan, or is it better to force the flue path up a few inches beneath the pan bottom?
Would putting a damper in the stack help keep some of the heat in? Or would the restriction reduce the firebox burn?
Thanks for all your help

[johnallin]

May also want to clean up the straw around the rig...big fire hazard with coals dropping out of firebox

[maple flats]

Most likely you only want 1.5" under the rear pan not 2.5". You want to push the heat up to the pan. One way to calculate it is measure the stack area, then divide that by the width of the arch, the answer is about how much space you want under the 3rd pan.

[Sunnyacres]

I'm confused my base stack is 6x22 and my arch is 24" wide that would mean I need 5.5 under my rear pan. That doesn't make sense to me could you please explain. I don't think I would want that much space under my pan.

[berkshires]

I'm confused my base stack is 6x22 and my arch is 24" wide that would mean I need 5.5 under my rear pan. That doesn't make sense to me could you please explain. I don't think I would want that much space under my pan.

The area of your 6" stack is pi x (radius squared).
R = 3"
R squared = 9"
9 x pi = 28"

So if your arch is 24" wide and you want to calculate how many inches you want between brick an pan to equal 28 inches, you divide 28 by 24, to get about 1.2"

That make sense to you?

GO