Block off plate - opinions please

[therealdbeau]

Hi all - just finished fitting my block off plate. Anything I should consider before caulking this thing in place? Also, is the high temp silicon going to hold up on the liner there? Not sure how hot that metal gets.

Thanks

Product used: https://www.grainger.com/product/ROXUL-2-x-48-x-24-Mineral-Wool-Foil-19NE83

 

[Ctwoodtick]

If I’m not mistaken, stove gasket material can be used around the liner. That should hold up to the heat. I can’t imagine silicone will.
I’m hoping your setup gets the seal of approval from the pros here, bc I like the looks of this material better than trying to contort sheet metal to my very uneven fireplace/ damper area ( installer removed some of the back firebricks to make insert fit ). I’ll wait to see.

 

[therealdbeau]

trying to contort sheet metal to my very uneven fireplace/ damper area ( installer removed some of the back firebricks to make insert fit ). I’ll wait to see.

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Thanks for chiming in. I too was left, by installer, was left with a choppy damper area so this was my best idea. I hope it works out.

 

[tadmaz]

Is there any sheet metal involved? Most say that the blockoff plate is to literally stop airflow up, not just slow the airflow. Not sure if the foil backing will stop airflow.

 

[begreen]

The foil should effectively block airflow. Is the product Roxul Curtainrock?

 

[therealdbeau]

The foil should effectively block airflow. Is the product Roxul Curtainrock?

Yes, Curtainrock 40.

Any ideas on the to seal around the liner? It's a really tight fit but I figured I put a bead of silicon around it but it probably gets too hot for the RTV. Furnace cement? for cram gasket material in there or just leave it be?

 

[Ctwoodtick]

I wound think gasket material. I suppose it could be easily removed if need be.

 

[begreen]

It looks pretty snug. I would probably not bother, but you could stuff in some thin stove door gasket material around the pipe there.

 

[BlackBetty06]

If you get high temperature silicon (the red stuff) it will hold up also. We use it on 10-12” boiler exhausts that regularly see high temperatures without problems. Of course if you forget to close the air intake you would likely see temps above what an oil fired steam boiler generates so your mileage may vary

 

[begreen]

Of course if you forget to close the air intake you would likely see temps above what an oil fired steam boiler generates so your mileage may vary

A wood stove flue can get over 1200º if the air is not closed down soon enough. Red RTV is only rated to about 600º. It gets pretty stinky when over baked at high temp.

 

[Easy Livin’ 3000]

Hi all - just finished fitting my block off plate. Anything I should consider before caulking this thing in place? Also, is the high temp silicon going to hold up on the liner there? Not sure how hot that metal gets.

Thanks

Product used: https://www.grainger.com/product/ROXUL-2-x-48-x-24-Mineral-Wool-Foil-19NE83

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Oh yeah, that's a great idea. I would totally steal your great idea, but my plate is going to be visible. Still might, just would need to hit the foil with some grill paint. Is the rock wool ridged or floppy?

I've made two failed attempts with sheet metal. It's really hard!

 

[Dmitry]

Cool idea, how did you make it stay in place?

 

[HomeinPA]

I like it but like Dmitry asks...what's holding it in place? Pretty much looks like you made it slightly oversize and wedged it in there which likely would work but it theoretically could slide down when someone runs a brush up and down the liner. I'd not worry about the seal around the liner as much as making sure it can't drop down on top of the stove.

 

[therealdbeau]

Is the rock wool ridged or floppy?

It is pretty rigid, I'm struggling to think of something to equate it too. Maybe like styrofoam - if you want you could break it in half but otherwise it is solid. Not sure if that makes sense.

Cool idea, how did you make it stay in place?

It is very much wedged in there. Also there is a small shelf in the back of the firebox from where bricks were removed that it sits on top. Combined with a slight forward slope to the flex liner it is stuck up there pretty goods. I figured I'd run a generous bead of silicon around the perimeter which I think will help further to keep it in place.

 

[begreen]

You could attach some 1" angle iron to hold it in place if uncertain.