My blockoff plate design...

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spidiracer

New Member
Sep 2, 2008
10
Utah
Okay so I saw a method on here to building a blockoff plate and here is the result of that:

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That's the single piece of metal with the edges bent down where you "wedge" the piece into place. There are several reasons that this way did not work well for me... Here are a few...

My hands were all cut up (like I got into a fight with a badger), the plate never fit very well... plus had I bonded it in it would have been extremely difficult to service the stove in the future... So I came up with my own idea...

I'm sure you guys have come up with this already but I am happy to report this idea brewed totally in my brain without any influence from the board. I'm posting this just to share (cause I'm proud of it) and to maybe save some people some hassle in doing it the other way.

Okay so this is really easy to do... What you need:

Tin snips
Metal Drip rail (I dunno exactly what its called)
sheet of flat metal
the fireplace bonding stuff
SS rivets
Rivet Gun
Drill and bits
Metal screws

Yeah I dont really know the exact name of all that stuff, lol.

Okay I should have taken pics of progress as I went... but its really pretty self explanatory. I did one corner of the chimney at a time and then simply riveted the four pieces together when I was all done. I riveted them together one at a time after putting where I wanted them to go in the chimney. This is the end result.

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Pretty simple huh?

Okay so you can see where I am going with this... So now take that and find a nice little place for it in your chimney and glue that bad boy in place!

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Now the cool part of this whole thing... You just cut the flat sheet of metal the the right size and make a hole in the appropriate location. If you screw up the hole location... no big just take another sheet and try again. With the other method if you screw it up your basically have to start all over and its a huge PITA!

Okay now I just placed it where I wanted it to go, and reached my hand up through the hole to put pressure on the sheet of metal so I could drill through the metal frame and the metal on top.

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I then took some fiberglass and peeled the paper backing off of it and cut that to fit on top of the plate. I placed that in there and then screwed it all in. The metal screws pull the metal sheet nice and tight with the metal framing and make a very nice seal :) I didn't even use and glue stuff here and its air tight.

Slide the chimney liner down and poof... your done. Now if in the future you get a different stove or want to change fiberglass all you gotta do is cut a new flat piece of metal and put it in place of the one you just took out. Super sweet! I'm probably forgetting something so any questions just ask. Like I said I am sure this has been done before or maybe is common practice lol... But i didn't see any instructions that were like this.
 
That's definitely an easier way to do it. Make a loose hole with plenty of wiggle room and then slide a tight fitting patch over the sloppy hole and liner. Thanks for posting the step by step. Did you note that at the bottom of the block-off plate wiki there are two links to forum member's installs? Their method is the same, but with kaowool, not fiberglass which will melt at higher flue temps.

https://www.hearth.com/econtent/index.php/forums/viewthread/11697/
https://www.hearth.com/econtent/index.php/forums/viewthread/9630/P15/
 
I did read about the koawool and I went looking for it but could not find it anywhere. I even went to my stove place... The guy told me there that I would probably have to order it online. I was in a hurry as its getting pretty cold here and he said regular insulation would work okay as it withstands 2000F. I do plan to order some now though and put it in as with this design its a pretty easy deal to swap it :)

And actually I never found the blockoff plate wiki I just was searching forum members posts... Oh well, lol. I'll take a look right now thanks for posting :)

Oh... and just a side note... My furnace controller is all the way across the room and on the other side of a wall and it has gone up 8 degrees in only three hours of the stove running with the blower :)
 
Make a loose hole with plenty of wiggle room and then slide a tight fitting patch over the sloppy hole and liner.

Oh wow that's a really good idea! I didn't follow you at first but when I saw the pics it all made perfect sense! Well I guess I can't think of everything, haha.

I have a laser temp gauge that I use for racing.. I am gonna use it to measure the temp of my block off plate to see if the temperature is going to be an issue with the fiberglass.
 
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