Having a hard time with block off plate

[tumm21]

So I made my template with cardboard and have yet to make the hole in the cardboard for the liner. What's the best way to figure the hole for where the liner comes down. I bent the edges of the sheet metal just need to figure the hole. I am attempting on doing the template with the insert in place. I have plenty of cardboard to work with

 

[fossil]

Cut it the best you can, trying to err on the tight side. If the fit's not good enough, trim it a bit. Make notes on the cardboard with a sharpie or something as you go. Start fresh if you wander way off the mark. Sooner or later, you'll have a really good fit. It doesn't have to be perfect. You'll git 'er done. Rick

 

[begreen]

Another way is to make the plate in two or three pieces that overlap and get pop riveted together. That allows you to see the liner and mark it.

Check out the examples at the bottom of this wiki article.
https://www.hearth.com/talk/wiki/why-damper-seal-is-needed/

 

[mwatt65]

I've been trying to this myself! tried to find someone to do it for $$$ going to tell the installer that according to the manufacturer its not installed right without one!
If I was smart last year I would of told the town to fail it for not having a block off plate!

 

[Hogwildz]

It is okay to error a little large on the hole, you can fill the gap with door gasket material which works great.
Thanks to Brother Bart for this knowledge

 

[weatherguy]

Cut your cardboard template in half and make half the hole on each part of the cardboard.

 

[Hogwildz]

Don't forget the make your template at least 3" or more longer for each side of the two pc plate if that is your plan, so you have a good overlap secure the two haves together. The hole will be two long "U" shapes on each half of the plate at the overlap, so that when they are mounted overlapping and fasted together, both "U"s will form the round hole, and you can screw overlaps together once the two pcs are in place.
Silicone is great for the perimeter flanges on the outside of the block off plate, but don't bother siliconing around the liner, it will not hold up. The two choices I know are furnace or stove door gasket cement, which will harden and usually falls out in time, or rope gasket.

 

[tumm21]

I just traced the hole for the liner on the sheet metal. I am thinking of making the hole about a half inch larger around the whole hole. Is that ok?

 

[bholler]

i wouldn't go that much larger no

 

[bsruther]

I intentionally made the hole in my BOP slightly bigger than the stove pipe to make it easier to position the stove and used a stove pipe ring to cover the gap. Worked out well.

 

[BrotherBart]

Mine is considerably larger than the liner. I just stuffed the space with Roxul. The 30 degree elbow goes through it at an angle so a tight fit wasn't gonna happen.

 

[brenndatomu]

I intentionally made the hole in my BOP slightly bigger than the stove pipe to make it easier to position the stove and used a stove pipe ring to cover the gap. Worked out well.

Stove pipe trim ring...that's a good idea

 

[Hogwildz]

1/2" is fine, any gap can be filled with door rope gasket material. Usually, where you think the liner is going to go through , is not where is ends up at the end.