Poor man's block off plate installed

[edge-of-the-woods]

Finally got around to doing this once I had some vacation time.

Prep Work
1. Got the materials, all from Home Depot:
One package of Roxul Safe n' Sound, $42.00
One package containing three 5/8" wing nuts, $2.00
One 12" long piece of 5/8" threaded rod, $1.75.
One 36" long piece of 1/8" thick steel, 1" wide, $5.00
Two pieces sheet steel, 12" x 24", 16 gauge, $17.00
Two 5/8" nuts, already had those laying around.

2. Took off the front of the stove, then the surround. The front comes off easy, all I had to do was unscrew the ring on the end of the rod that moves the cat back and forth; then the whole face just pulls free. Next, two screws were removed that were keeping the surround attached to the stove body. Those came out, and the surround lifted right off. Then I took a picture of how the blower fan controls (built into the front) connected from the blower, disconnected them all, and removed the front and surround to another area.

3. Took a good look all around the stove, up inside the shelf and the chimney, got a feel for how the Roxul would go up, and where the support struts for the sheet steel would go. Took some pics. Cleaned out some masonry debris from the top of the shelf, which was there from when the masons demo'ed the top of the chimney last year and rebuilt it. Cleaned and vacuumed it all out.

4. Cut the threaded rod in half to make two pieces. Measure the damper opening and cut the steel bar to span it securely, making two 9.5" pieces. Drilled one 5/8" hole in the center of each support bar. Didn't have lock washers so I deformed the threads on one end of the rod pieces so the nuts wouldn't slip when I put them on the ends.

5. Spent a while measuring and cutting and shaping the sheet steel into two pieces which would snugly cover the opening. This took the most time and was the most effort. The liner goes from the stove up the chimney at a weird angle, so I had to shape a weird opening in one sheet, and have it overlap the other one. It's tight in the area where the stove is, and it was hard to get my arms up in there, and the pieces up in there as I was working on them.

6. Tightened the nuts onto one end of each rod, and slipped the rods into the holes in the struts. Then I found the best spots for the struts to span the damper opening, and marked those locations. I eased the sheet metal pieces up into place and checked where the rods would make contact, then drilled 5/8" holes in the sheets at those locations.

7. Opened up the Roxul to see what I was working with, see pictures. It comes in batts within that bale, it's not loose like cotton candy. More like layered cake. Folks on the web say you can cut it with a bread knife, but I just pulled hunks off by hand. it was slightly messy to work with, but not itchy. It tears apart easily, like huge slices of bread.

Installation

1. Stuffed around the liner as high as I could reach with Roxul, then packed it all the way down to the opening. This took a while, and I had to use chunks of varying size; big pieces for the beginning, smaller pieces at the end and behind the liner. The stuff is already compact and dense, so it doesn't wad up in the cavity the way that fiberglass or a cotton-candy-type material might. You really have to keep jamming it up in there, and it will keep falling down until it's packed tightly, and you have the plate in place.

2. Once one side was stuffed full, I put the support strut in place across the damper opening, then slid/pushed the sheet steel almost into place. I guided the dangling rod through the hole in the sheet steel, and got the wing nut on the end of the rod. Get the wing nut on fast, because holding everything in place was tricky. Then I pushed the sheet steel into final position, and fastened the wing nut all the way up against it, securing it in place.

3. Did the same thing for the next side. It went easier the second time, and the pieces fit very well over each other, and across the opening. The Roxul stayed in place pretty well on it's own, but the sheet steel was needed for sure, because I could see that the Roxul could shift and fall down over time. The sheet steel kept it up there quite securely once it was fastened to the struts with the wing nuts.

Pictures

Pictures show the stove with the front and the surround off; the left side of the opening; the right side of the opening; the Roxul bale, one of the sheet steel pieces, and one rod/strut assembly; what the Roxul looks like inside the package; the packing of the left side with Roxul; the left side packed full with the strut/rod in place; and the left side with the steel sheet screwed into place.



RESULTS

So far I was only able to have one fire to test things out, and it was 65 degrees outside on Christmas day, so I don't think it's really a true result. at least I hope not, because after all this, it didn't seem like the house got any warmer than usual! With the temp set at 62, the temp in the house got up to 71 with a small fan running a convection current, which is only 2 degrees warmer than usual. I'll have more data to report when we're back in town in a couple days, and it gets back down to the 40's and 30's like it should be.

 

[jatoxico]

Good job EOW. Filling that smoke shelf with Roxul and air sealing will improve liner performance for sure. After doing mine temps measured on the outside of my exterior chimney dropped dramatically. Retaining that heat will keep the flue gases hotter which means you can cut the air more and still run clean. The amount of soot I get now compared to before is much less and it's the brown ashy type not the black crunchy so much better.

I found my insert runs a little warmer for a given load of wood but stays hotter much longer. If you want, slide the insert forward an inch or so and you can let some of the heat out from behind the surround. Being a flush mount that can help some. If that's an exterior chimney you may also want to insulate the firebox walls with the Roxul you have left over. If it's interior it's probably less important.

 

[edge-of-the-woods]

Thanks man, and thanks for the advice! I will definitely try pulling it forward some, trapping all that heat back there has been a concern of mine. I'd rather have it out in the room. I had a thread about heat lsot/trapped back there and had mentioned cutting some holes in the surround, but peoples' opinions on that were mixed. The surround is DEFINITELY a LOT hotter now than it was. The edges used to be cool to the touch, now you can't keep a hand on them for more than a second or two.

My one concern with pulling the stove out a bit is the same I had with replacing the solid surround with one made out of perforate steel sheet: what about dust and dog hair that gets back there? Is that a possible fire risk?

I was thinking of getting a surround made out of this stuff:
http://www.metalsdepot.com/products/hrsteel2.phtml?page=perforated steel sheet&

 

[jatoxico]

Check out some of the threads on insulating the firebox for ideas. Looks like yo have a decent amount of room to work with (unlike me). Inch it forward as a test to let some heat out and see what you get. If there's that much heat back there maybe you want to take it a step further or insulate the exposed liner. Personally I'm all about keeping the flue gases hot and heating w/ the stove not the pipe but I have a pretty long exterior install.

 

[Dmitry]

You are lucky to have all this place to work with. I can barely squeeze my hand around my insert. Thank you for the idea of making suspended block off plate instead of fixing it in place by drilling masonry . Now I'm thinking in new direction.

 

[edge-of-the-woods]

You are lucky to have all this place to work with. I can barely squeeze my hand around my insert. Thank you for the idea of making suspended block off plate instead of fixing it in place by drilling masonry . Now I'm thinking in new direction.

Just patterned this after another thread in here, that guy gets credit Thanks though!

 

[edge-of-the-woods]

So after a few overnight burns in cold weather, I will say that once the insert gets burning, it's noticeably warmer in the house. We'll get up to 72 degrees in the whole living area, when before we were getting 70 degrees with the guest room and office closed off. I'm also getting a nice coal bed to start over from in the morning.

On the con side, it is a LOT harder to restart the stove if it burns down. Getting started from a warm/cool stove is as difficult with the block off plate installed, as it was when I was using wood that was too wet. It takes a lot longer to get a good draft going. Before I could rake the coals forward, add a dry split, and woosh! Fire going. Nor I have to start with small kindling, get that going, and add a split.

 

[jscs.moore]

So after a few overnight burns in cold weather, I will say that once the insert gets burning, it's noticeably warmer in the house. We'll get up to 72 degrees in the whole living area, when before we were getting 70 degrees with the guest room and office closed off. I'm also getting a nice coal bed to start over from in the morning.

On the con side, it is a LOT harder to restart the stove if it burns down. Getting started from a warm/cool stove is as difficult with the block off plate installed, as it was when I was using wood that was too wet. It takes a lot longer to get a good draft going. Before I could rake the coals forward, add a dry split, and woosh! Fire going. Nor I have to start with small kindling, get that going, and add a split.

 

[jscs.moore]

It's interesting that you would have more trouble re-starting the fire with the block off plate? I don't have one (yet), but my insert does draft really well and all I have to do to restart after burning down to coals is add new splits an whoosh...it's cranking again! I'm a newbie and still learning my insert (Hampton HI300), if I proceed with a block off plate it will probably be next year...but I would have thought restarting a fire from coals with a block off plate would make things easier...not more difficult? Why do you think that is?

 

[edge-of-the-woods]

My guess is either A) it takes longer to heat up the liner with it only being heated from hot air going up through it, instead of all around it and through it, or B) something completely not related to the blockoff plate, that I haven't thought of...but someone wiser will surely explain to me

 

[jscs.moore]

My guess is either A) it takes longer to heat up the liner with it only being heated from hot air going up through it, instead of all around it and through it, or B) something completely not related to the blockoff plate, that I haven't thought of...but someone wiser will surely explain to me

Yes...we need some "pearls of wisdom" from one of the moderators to explain this one