Do I need archboard?

[bison1973]

I'm bricking a new Maple Pro 3x10. I'm going to be using full size firebrick. My question is do I need to use the archboard first? I asked my dealer and he said not to if I'm using the full size brick. He said I'd be wasting my money. I questioned him and he still said not to use it. What do you guys think?

[mountainvan]

Even with full brick the sides of that evaporator will get hot after a couple hours of boiling. Using the arch board not only helps keep the heat in the evaporator, but makes it more comfortable to stand next to the evaporator. I say use the archboard in the firebox and ceramic blanket under the flue pan. A well insulated arch makes making maple syrup more enjoyable and saves on fuel and time.

[RileySugarbush]

So what exactly is archboard?

I'm about to get some insulting materials from a local refractory supplier, and they don't know of the term. I assume it is specific to maple evaporators. They have several board like products including mineral wool board and ceramic panels. I got a comment from them that the mineral wool boards have some organics that smell as they bake out.

I was thinking of using half bricks and board in the firebox and blanket/vermiculite in the flue. How does that sound?

[HanginAround]

I would use the board too. Regular firebrick is actually a pretty poor insulator.

Arch board is a mineral fibre insulating board, doesn't look all that different from drywall, a bit fuzzier. It cuts easily with a utility knife.

Edit: I posted this last spring, you can see the board across the back where I haven't bricked yet. Big pic, give it a minute to load:

http://www.thepixplace.com/img82543.html

[hard maple]

Bison use the board!
anyone who didn't use it probably wishes they did.

[tapper]

I had full brick and a thin layer of regular building insulation in the 2x6 I used to have. It would get terribly hot beside that evaporator ,you could not stand there. I burned the knees out of a good pair of rain pants one day and didnt know it till it was too late. I put 1" ceramic blanket and full brick in the new evaporator and after 1 1/2 hour you could still touch the outside of the arch with bare hands.

[bison1973]

Yes, I'm going to use archboard. Will the half size bricks be sufficient if archboard is used?

[tapper]

Use full brick all except for the top course directly under the pans. Use the half brick or splits on the last course to allow more heat toward edges of the pans. See my pictures I believe there are a few that show this?

[HanginAround]

It seems the half thick brick is almost the same price as the full, so not much reason to use it.

[bison1973]

I'm getting the evaporator tomorrow. My dealer says if I use archboard not to use full size brick because it will take up too much space in the firebox. I know the archboard is a good insulator. So my question is... is there any real difference between using full and half brick if you use the archboard? If not I'd like to use the half brick because it would be easier to cut and work with.

Your comments please.

[HanginAround]

I think you'd be alright, but don't really know from experience. An inch of archboard should be a much better insulator than an inch of brick, and I think the archbrd is rated at 1900 F (?), so should be fine behind an inch of brick. One thing, the half thick brick won't stand up to being thumped by sticks near as well, and the whole wall will be more likely to flex and move and break out the cement especially when backed with something with a little give like archbrd. I still think it should be fine though, small evap, you can be careful, and easy to see and get at if a problem arrises.