insulation?

I did not use a metal block off plate. I stuffed un-faced fibeglass insulation in the damper are to seal between the ss liner and clay liner. This was recommended by someone on this forum who is a chimney sweep. It has been working fine.

Faced means paper which means burn.

Unfaced means fiberglass which means SO2, which means oxidized already, which means no burn.

I haven't poured it in yet, but I got a big (4 cu ft) bag of perlite on Ebay that I'll pour in around the liner from the top. It should fall on top of the block off plate and be like blown-in hi temp insulation.

You can get mineral wool insulation in 2" thick batts from mcmaster-carr (the source of all good things).

Most wood install manuals specifically state NOT to use fiberglass around your wood liner. If I remeber correctly from other discussions, its melting point is lower than the maximum rated temp for the liners (2100 F).

I put un-faced fiberglass in my damper area a month ago. This is a temporary fix until I get my liner insulated and block off plate installed in the spring. I run 24x7 and haven't had any smell or melting issues thus far. I'm not sure what the liner temp is when it's at it hottest where the insulation is, but if it's near 2000 degrees, I think I'd see me stove glowing, eh?

The 2100F rating is designed to withstand an out of control chimney fire. You should not get temps close to that unless you have a chimney fire. But if you are going to have a 2100 deg liner system you dont want to add in components that cannot withstand that.