bricking 18x48 cdl wood fired evaporator

[emq]

I'm bricking a new CDL drop flue evaporator with 5 inch flues
my question is do i just need to brick the fire box and use arch board for the rest of the evaporator?
I laid out the arch board and brick on the part under the flues and set my pan down and
there is not enough depth with the brick. should i use vermiculite on top of the arch board or is the arch board sufficient
thanks

[ecolbeck]

I have my evaporator set up with firebrick in the firebox only. There's more room for insulation under the flues if you omit bricks in that area. Another benefit is that there's less mass so the evaporator comes up to temp quicker on startup and cools off quicker on shutdown. I used perlite to level out underneath the flues before adding a layer of foam board above it. I tried perlite above the foam board one year and the flue gasses caused it to move around.

[NhShaun]

Are you using 1" thick bricks?

[emq]

Are you using 1" thick bricks?

Yes using 1 inch bricks with 1inch arch insulation board