raised flue gap between flue pan and insulation

[dhbiker1]

I finally got around to bricking the arch and used vermiculite in the back section. Since the vermiculite is a small grain size, I am either going to put 1/2 brick or ceramic board over it. My question is how close to the frame should it get in the vertical direction for the center, sides, and where the gap is between brick/board and smoke stack frame.

[chipa]

I used ceramic blanket over vermiculite on the deck of the arch. The blanket touches the flues past the "baffle" (the metal slanted piece on the deck).This keeps the flames up in the flues. At the end of the arch , just shape the blanket so the flue gases can travel up the pipe. Make sure you put blanket at the end of the arch to protect it (under the base stack collar)

[brookledge]

I used brick over the vemiculite so nothing would move around, that way when i brush my flues I don't have to worry. I probably have around 1/4" to 1/2' between my flues and the brick.
Keith

[maple flats]

I did the same as Brookledge, brick over vermiculite with about 1/4" space, forcing the flames into the flues. I also squared the rear of the firebox area, up to about 4" flom the bottom ov the pans and then ramped up in the next foot to the 1/4' for the rest til the last ft where it drops down to exit the stack. It worked great on my 3x8 this way.