What to Use for Block-Off Plate

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El Finko

Member
Aug 22, 2012
161
Mason Dixon Line
Haven't made mine yet. I picked up some duct-grade sheet aluminum(?) with the thought in mind, but I just wondered to myself if this stuff will take the heat?
I bought it because it's cheap.
What has everybody else used?
 
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How thick is it? It needs to be rigid enough to hold its shape. I used 22 gauge aluminum sheet, worked great. It has a melting point of 660 celcius. If it melts, you have bigger problems!
 
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it's whatever they sell at the box store in the ducting aisle
I think it's galvanized aluminum
not sure what gauge
 
The flat stock duct material at HD or Lowes is fine, and what most use.
 
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Hogwildz you the man!! just a shout out
 
http://www.homedepot.com/p/UltraTou...1-16482/202709974?N=5yc1vZbvev#specifications

Is this appropriate for the blockoff plate insulation? (I dont see Roxul at HD) Thanks!

Now I found this:

http://www.homedepot.com/p/Roxul-Sa...ulation-12-Pieces-Package-RXSS31525/202531875

OR, we will have flexpipe liner insulation left over, know if we can use that?

Thanks!

Um, the first item does not appear to be fire-resistant...it's ground up blue jean material. :)

The second is what you want. You can also source 2" Roxul hard board. I bought both and ended up just filling the cavity above the plate with the compressible stuff.
 
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Left over liner insulation is fine.
No on ultra touch, yes on Roxul.
The sheet metal can be bent with any kind of metal brake. I used hand brakes, although if you have a larger one, it would make it easier.
You can use silicone to seal around the perimeter of the block of plate, and stuff stove door rope gasket in between he block off plate & the liner to close any gap there.
Enjoy your weekend.
 
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it's whatever they sell at the box store in the ducting aisle
I think it's galvanized aluminum
not sure what gauge
I actually just picked up some of the same stuff today with the same intention. Everyone here says it should work just fine. Hope your install goes well. I'll be getting to mine this week.
 
I made mine from flat sheet metal about the thickness of of us quarter. Bent it with a 2x4 on top and bottom with 2 screw C, clamps holdimg on the line to be bent around.Just grab and twist clamps and rool with board Worked like a mtal brake . I wouldent use galvinized metal it could start to out gass around 700 deg. under constant heat I was told by a metalergest. Alluumin will warp and sag before it melts.
 
I picked up the thinner sheet metal that could be bent by hand (over a 2x4). The heavier stuff is unnecessary -- more expensive and more difficult to cut/work/bend.

Speaking of cutting -- wear leather gloves and use tin snips. Snips will sail right through the lighter stuff. Take your time and have a supply of bandages on hand.

I packed the Roxul batts in above my blocking plate. Plenty of insulation up there, no need to use gasket material to seal the blocking plate to the wall.

For style points, though, you do need to spray the plate with high temp black paint. :)
 
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Lol, I cut myself each time I made one and I wore gloves, don't ask me how
 
Pulled the stove out today and started to make the template for the blockoff plate. In doing so I could feel a really big cold draft coming in. I placed pieces of Roxul to block up the opening of the but still can feel some drafts. So I would like to know how much Roxul do I put up there? Above the damper area is a huge space and then tapers smaller as you go up.
One more question the insulation wrappped around the flue was wet is this common or a problem?
Thanks
 
The insulation is not an air seal, so it will not stop the draft. That is what the block of plate is for.
The wetness is not normal, and means you have a leak somewhere. Most likely up top. If it has a storm collar, it may not be sealed good. If it doesn't have a storm collar, you may need one. Depends on what is up top.
 
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