Fire Brick vs Concrete Brick

[obsessed]

Last year I just used some old concrete bricks I had laying around for the inside of my barrel stove. I noticed the stove was significantly cooler on the outside where I had bricked. Why should I use fire brick instead of just concrete pavers? Are they really worth the cost?

I am also figure out how to build a wall to even the heat out. It was discussed that I bring a wall to within one inch of my back pan (I have 2 steam pans on a barrel stove). I assume that the area running parallel to the ground under the second pan would stay at that height until it reaches the exhaust. Meaning there is no area where it opens back up.


Like this
Pan Pan :EXH:
:______::_______L :
:_______________:
_______: :

[ecolbeck]

Concrete pavers will disintegrate rather quickly. Unsure of why they seem to insulate better.

I don't understand your diagram but what you wrote seems correct. Keep the ramp up close to the rear pan all the way back to the flue exit.

[Cjadamec]

Concrete insulates better because it has air bubbles trapped in it. Fire brick has no air in it.

The trapped air is part of what makes concrete fail in a fire.

[obsessed]

Yes. I meant where I had bricked was much cooler on the outside than where I had not.

All the concrete bricks survived last year, so I guess I will just continue to use them this year.

[TapTapTap]

Since the bricks are still ok then I assume that your rig doesn't have a blower. My bricks are cherry red when I'm fired up which i think would destroy regular cement-based bricks.

[maple flats]

If regular concrete bricks held up, you need to fire it hotter. When fired properly the concrete bricks will fail. I bricked my current arch for the 2008 season using fire bricks, they are still good, with concrete I'd need to re-brick every year or 2.

[Swingpure]

Not sure what thread I should ask this question on.

This past season, I fire bricked my fire box and it certainly protected the concrete blocks, on my cinder block evaporator. This past season, I had a block above the twomcinder blocks that stuck out for the pans to sit on. Coincidently the block that stuck out was just the right height for the fire bricks to be wedged under them. So the firebricks were simply stacked.

This picture in one sense is a bad one, as I had not pushed the bricks back before taking the picture, but does show how they were loosely stacked. I did have them tight together and they never fell out during a boil.

https://share.icloud.com/photos/08d5k0f_02kBGRhCx3cl1_kmw

My problem this coming season, is I will not be having the block that sticks out, as my pan will sit on top, so nothing to wedge against.

I was thinking of having a piece of angle iron up top that the pan would sit on, with the angle pointing down, and only out the thickness of the fire brick. This would allow the top firebrick to be wedged in and held.

Is this a good plan?

[Pdiamond]

Using the angle iron is a very good idea. Make a square of it that the pan can sit on. You'll use some rail gasket and the pan will be sealed and no smoke will get out and no air leaks. You can get the rail gasket from your local maple supply dealer. You don't have to buy a whole roll just how many feet you need for your pan. It is okay to overlap the corners as long as it is the same on both ends.

[Swingpure]

The manufacturer of my divided pan tells me that 3/4” of the four edges of the pan should sit on, in my case, the concrete blocks surrounding the firebox. With having 1 1/4” thick firebrick along the two long outside walls, and assuming you do not want the firebrick to be used for pan support, then that means that 2” of the 4’ long edges of the pan will not be directly exposed to the heat.

Is that okay?

Thanks

[Bgreisch]

you could always keep your fire brick lower than the croncrete block, that way the heat can get to the edge better. I have a Dauntless evaporator from Smokey Lake and the fire brick does not go all the way to the top but there is also insulation between the brick and the evaporator wall.

https://www.smokylakemaple.com/product/dauntless-evaporator-with-divided-pan/

Bryan

[Swingpure]

you could always keep your fire brick lower than the croncrete block, that way the heat can get to the edge better. I have a Dauntless evaporator from Smokey Lake and the fire brick does not go all the way to the top but there is also insulation between the brick and the evaporator wall.

https://www.smokylakemaple.com/product/dauntless-evaporator-with-divided-pan/

Bryan

Thanks

I had planned on having an angle iron frame on the top concrete block, to hold the fire brick in place, so that would mean the fire brick would have to go right to the top.

The other choice I guess is to use masonry cement on the concrete blocks so they do not move, then use high temp refractory cement to attach the fire brick to the concrete blocks and stop short of the top. The down side of that is that the evaporator would become permanent, and I had planned on removing it during the summer period to use that space, as well it would make it difficult to replace a specific concrete block if it gets heat damage.

[Swingpure]

Thinking about it, the angle iron, if attached to the concrete block away from the edge, would likely have the strength itself to support the pan, thereby not putting any structural stress on the fire bricks.

[mdm1]

I posted a question about using road brick for firebrick. My one thought just like yours was if the pan is supported by the cinder block I would not have the area of the brick under the pan getting heat. Hope that makes sense. I would be making my firebox smaller. But if I made the metal frame study enough the pan could be supported on the ends only by the block. The metal would support the long sides of the pan. Maybe more thought than needed for my micro hobby.

[Swingpure]

Checking with my local steel supplier, I can get 4”x2”x 1/4” angle iron. The 2” is more than I would want, but does not hurt. I would space my cinder block walls, so that I had a 22” gap between the two pieces of angle iron. The pan would sit 1” on the sides. I would then screw down the 4” part of the angle iron into a solid concrete block, so that it was very solid. I would put gasket material on top of the angle iron for the pan to sit on. I would just have 1/4” thick pieces of flat steel at the two ends.