How hot?

[mike z]

Ok, started the first fire today in the new home-made evaporator. I was a little dissapointed in how hot the stainless sides got. I put in 3/4 ceramic blanket, faced with full size fire brick. I suppose I squished the blanket more then I should have. But the dog-gone firebox was shrinking up fast. How hot are your side?

[C.Wilcox]

How hot? Plenty hot enough to burn me, that's for sure. I have archboard covered by 1/2 bricks and the sides got hot enough to warp and break a bunch of the brick.

[mike z]

I don't know if that makes me feel better. Anyone else?

[tapper]

I have 1" ceramic and full fire brick. Stays nice and cool for the 1st hour after that it gets pretty darned hot!! But the ceramic has prevented the stainless from turning blue.

[Dennis H.]

I will let you know how mine does soon, I put in 1" arch board then 1" firebrick(splits)

I think that the the sides will be hot with just 1" blanket and bricks. The bricks are not very good insulators. Once they get hot they hold the heat and they will transmit the heat really good. The blanket and archboard is what will insulate the arch and keep the heat in. If you read about the new super effecient evaps that are out there they use multi-layers of blanket and very little brick.

I think you would have been better to use more blanket/archboard and then use splits for the fire brick.

[red maples]

Yes the sides of the firebox will get hot!!!!

hot enough to steam off water(or sap) but sap will leave little black or brown spots! hot enough to melt pastic...don't let your pre-filters touch it they will melt:(

I have mine with arch board then full bricks and it stay cool enough to touch for about 1/2 to 3/4 of an hour but once everything gets hot!!! its hot!!!!most are that way its to be expected. you have some serious combustion going on in there it will be enough to make your arch front glow red!!! and it will!!! which is in excess of 1200 degrees which I think is the temp that cast iron will glow. When all of the fire is out look at the bricks at the base of the arch right at the egde of the grates they will be glowing red!!!!

If your bricks are warping and breaking I wonder if you have firebricks. those babies are designed to take the heat!!!

[C.Wilcox]

If your bricks are warping and breaking I wonder if you have firebricks. those babies are designed to take the heat!!!

Red- They're definitely firebricks, it's just that I mortared them in with a real tight fit so when the sides started to warp it was a case of something having to give. The brick was weaker than the steel so it lost.

Mike Z- You're basically creating a forge inside your arch when you fire it. I think that unless you got crazy with the ceramic blanket or archboard the sides will always be hot. The idea is to keep it as cool as reasonably possible. If you're feeling bad about it just go watch one where they didn't insulate it. The sides will glow red and you can hardly get near it without losing your eyebrows. If it's a really a concern you could stack concrete block/brick up in a free-standing wall along the side to keep people from accidentally brushing into it. My father in law did just that using pavers and he left spaces between them in the wall so the heat could get out, but the kids couldn't run into the stove. Worked well.

[Sugarmaker]

Mike Z,
I have stainless sides and no blanket between the firebrick and the sides. They get very hot hot enough to turn the sides blue. But I have not had any brick crack.
Chris

[mike z]

Thanks for the comments guys. I suppose a little heat will be a welcome thing. Just not too much.

[markct]

my arch has forced draft with air over fire and under, and 1 inch arch board with half bricks covering it on the sides of the firebox, and 1.5 inch ceramic blanket doubled up in the rear part. after an 8 hour boil i can touch the sides with a bare hand for a second and not get burned, but cant hold your hand on it.

[Pete S]

Anything you use to protect the combustion area of your evaproator will transfer heat. After time the outside is gonna get hot!

My opinion is that the fire brick does as much to protect the steel from "burning through" as it does to reflect "some" of the heat.

Without the brick/blanket/board the steel/metal would burn through in short order.

[Brent]

Mike
Lots of guys run their arches so hot that the grates under the fire warp, especially if they are not made from heat resistant alloys of iron and steel. It's really hot in there.

After 3 hours or so of boiling, our sides are so hot that and syrup that splashes, will scorch black in seconds. That's with 1" archboards and half thickness bricks. The sides are dangerous. Synthetics will melt on contact eg ski-jackets, snowmobile suits etc. Be real careful with kids !

[lew]

I realize you guys are using wood and need fire brick, but my oil fired rig has 1.5" doubled up in the fire box area and also all the way to the rear. I can hold my hand on the fire box after a 12 hour boil with no problem so long as it's not within a foot of the top rail. Even though the sides are well insulated, eventually the top rail gets hot and transfers heat down the outside. But the heat has to travel from the fire ball to the top rail then down the outside. Takes quite a bit of time to get her warm.