Register/closure plate materials: Steel or masonry board?

[CharlieTuna]

I checked the folks chimney and there is no register/closure plate above the stove. So, there is only a cap on the top. I still need to get the stove out to get a better picture of things. I assume that most use a steel plate in there. I suspect that some kind of masonry board would be better because it expands less with the heat, doesn't rust, etc. Has anyone tried this? I found this guy from the U.K. has a few videos about making a plate out of steel and installing it in a stone masonry chimney:

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He has metal access doors in his for cleaning. With a chimney liner, is that really necessary? I think I would rather try to seal it up as much as possible to keep the heat in the room and not leak up the chimney. With all of the expansion and contraction, I don't know how well that can be controlled.

 

[begreen]

Simple galvanized sheet metal works fine. There shouldn't be a moisture issue in this location.

 

[CharlieTuna]

Simple galvanized sheet metal works fine. There shouldn't be a moisture issue in this location.

I would think that aluminum would have better thermal qualites than steel to try to keep heat from radiating up the chimney. Aluminum relects radiant heat well rather than radiating much of it. I am also thinking of pouring some perlite down around the chimney liner as insulation if possible. The only reason I can think of not to do that is that it would make a mess if there is a need to service the liner.

 

[kennyp2339]

The problem with masonry board is that overtime it starts to crumble.

 

[bholler]

I would think that aluminum would have better thermal qualites than steel to try to keep heat from radiating up the chimney. Aluminum relects radiant heat well rather than radiating much of it. I am also thinking of pouring some perlite down around the chimney liner as insulation if possible. The only reason I can think of not to do that is that it would make a mess if there is a need to service the liner.

Don't pour perlite in it will leak without question. You simply cannot seal all of the dissimilar materials together well enough. Just get some rockwool stuff a bunch up there and install your metal plate over that. Galvanized or aluminum is fine.

 

[CharlieTuna]

Don't pour perlite in it will leak without question. You simply cannot seal all of the dissimilar materials together well enough. Just get some rockwool stuff a bunch up there and install your metal plate over that. Galvanized or aluminum is fine.

Thanks for the replies.