Slab Insulation Panel

I was reading Page 65, step A10 - 45" x 27" Refractory Slab Insulation Panel. Step A9 states to mark and cut 7 sections, and step A10 says I should select the 5 best pieces of foam to glue together. Not 7, but 5.

It also says to place glue on each of the (3) pieces (not 5) and connect them together. Based on the picture on step A10, I think I am connecting 3 together and two together.

Can someone verify this?


Hello Mariela and welcome to the BrickWood forums! Congratulations on building a BrickWood Box. That’s going to be one amazing cooker when you are finished.

As you’ve seen, there are phases to this, and the foam inserts you are building in Phase A get used somewhat later in the process. As I read the instruction, here’s what I get, step by step, along with my own interpretation:

  • (from step A9) Cut 7 pieces of foam. (Foam doesn’t always cut neatly, so you’ll come up with a couple of raggedy pieces.)
  • Choose the 5 best-looking pieces from the previous step.
  • On 3 of those pieces, apply Gorilla Glue to the adjoining faces, spray with water, and carefully align them. Stack them, and place a concrete block on top to weight down the 3 pieces. (You need the water because that’s what Gorilla Glue reacts with to form a strong bond. Foam does not have any moisture in it.)
  • (Extrapolating from the graphic) Take the two remaining pieces of foam, glue them together in the same way, stack them, and place a concrete block on top of them to weigh it down while the glue cures.

Now, what happens to the foam you cut?

  • The smaller stack (2 pieces) gets used pretty quickly, in step A20.
  • The larger stack (3 pieces) has to wait a long time, until step E16 (p. 94). Keep it in a safe place until you need it!
  • And the two pieces you didn’t select (pieces 6 and 7)? They are just trim, so that your smoker exhaust panel ends up with the correct dimensions. You must cut all 7 carefully so that the big panel stays squared at the corners, but you can discard pieces 6 and 7.

I hope this clears things up, Mariela, and I hope you will post often letting us know your progress and any further questions that come up. I’ve moved this thread into the BrickWood Box section, where there’s a number of folks who can share what they’ve learned.

Best of luck to you!

I know that @BrickWood’s instructions are exhaustive. But, unlike a “kit” that is really a knocked-down assembly, you will end up with a beautiful oven and smoker that you built from the ground up. And you always have us here to answer anything that is unclear.

I really mean it when I invite you to post your questions. In all the time I’ve been here, I haven’t run across a dumb question yet! :slight_smile:

Good luck, and please do keep us posted.

1 Like

Well, I have advanced a little bit. I waited a long time on the bolts and screws. Once we got them, we were able to build the Slab Insulation panel.

We have not placed it yet, but we also have part of the base (first line of blocks) and will finish it today. We will wait for the lower oven kit to finish as we need the wall liners.

I have a couple of concerns:
I used 2" foam because I could not find 1.5". That means the opening in the middle (insulation mix) will be a bit thicker and will have more insulation, but at the same time, the slab under it will be a bit thiner.

I know the slab gains strength with the metal fibers and those two bars in the sides, but there are firebricks to place and perhaps a large pig to roast.

The entire slab is 3.5", minus the 2" foam in the middle. That only leaves 1.5" thickness straight in the middle of the slab. Do I need to worry,

Also, I ended up with a couple of fiber bags left because I used less mix.

Any comments/ideas?

Sorry about the delay in getting back to you on this. I just caught it…

For the first BWB we made, we used a 2" foam sheet to make the insulation later (which left a 1.5" refractory slab). That was over 5 years ago and there is no cracking to date.

GRANTED - I wouldn’t want one of my kids standing in there… but we’ve had no problems w/ a 90lb suckling.

1 Like