advice for next season mods, not getting the boil I had hoped for

[dgdm]

I built a 2x5 oil tank arch, insulated with roxul comfortboard, firebox lined with fire brick, about an inch between the flat pan and the back section of arch. good grate and a small blower pushing air under the fire. I am only getting a boil over the fire, just steam in the back of the arch. the boil I am getting is underwelming. best I think I have hit is about 6 gallons per hour, but usually less. I have been using small pieces of dry wood, and old plaster lathing which burns like mad. but mostly hardwoods. the pans were made by a friend, when I went to pick them up discovered that he made them out of 14 gauge stainless! twice as thick as 20 gauge, they will last forever, but wondering how much boil I am losing. one thing I have considered is to lower the top of the arch so that it will be easier to get the fire contacting the pans. I can lower everything 4 inches and have no space over my door fairly easily. My blower works OK, it is the blower from a woodstove, directed under the fire, seems to work best at the front of the grates, when I rake coals over the front get a good boil in front 1x2 pan. wondering if AOF would help, I need to do a better job of sealing the arch to push more air, as it leaks from under my 2x2 angle rim. considering a copper line preheater around the stack as well.

Any thoughts? I am in no mood to replace the 14 gauge pans, i havent even got a bill for them, hopefully they are reasonably priced.

thanks

David

[bill in il]

I built my pans from 11 gauge stainless (cheap seconds) and I still get a good 15 gallon per hour boil off my 2x6 with AUF. So with that in mind it's not the thickness of the pans cutting your boil. The rest of the arch looks ok as well. I think I would spend my time sealing it up better, possibly use a larger fan? If I remember correctly mine was 150 cfm.

Another note would be are you using well seasoned wood? Are your pieces small no bigger than 3 inches? It takes a roaring good fire to make a good boil.

[sweetwater sugar shack]

One thing I see on your arch I would use half bricks on your top row and it does not look like u have much of a gap where your flue is have u checked your stack temp? What size stack do u have

[mellondome]

Block off the front 6in of your grate. The air is going up the door and across the pans instead of up through the fire

[Sugarmaker]

What is your goal? You are at 6 gph, I think you have flat rear pan right? Maybe you could tweak the arch and AUF to get 10 gph. Would that be enough? If not look at a new flue pan. 22 or 22 gage would boil a little better too.
Just keep pouring the wood to it, and have fun!
Regards,
Chris

[chad]

dry poplar slab wood from a saw mill would be a better wood choice, hardwood makes coals that block the grates and burns slower softwoods like poplar and basswood burn fast and hot- you want flames not coals, you're boiling sap not heating your house

[BarrelBoiler]

hi
the things I would change

go with the thinner fire brick on the sides of your fire box. you are losing heating surface the way your
bricks are arranged could do just the top row that would uncover more of the pan bottom

lower the back shelf some you may be choking off the draft if you have some smoke coming out of little gaps
when the fire is going good the draft is not good I have a barrel stove that has several blowthrough welding holes they smoke at start up but once the fire gets going they are sucking air

and/or

lowering the last 2-3 inches at the back of the shelf for an easier exit for the smoke to the stack
the first barrel stove I had exited the back to six inch pipe I took the shelf as far back as I could but soon found out I needed to open up the back some to let the whole thing breathe better this resulted in the draft going as directly as possible to the stack I added a brick I front of the stack on the shelf to block the direct route and made the smoke/draft/heat go more to the sides

sorry for the long post hope this helps

steve