Simple Baffle Solution for your old FISHER ! More Heat Less Smoke under $25

[jjs777_fzr]

Hello all, new member here, just joined today. What a fantastic Forum! I have had my Fisher stove for 31 years and recently decided that I would like to decrease the amount of wood cutting/splitting that I do so wanted to increase my stoves efficiency. I thought about the new baffled stoves and sketched up a baffle for my stove, decided to Google it and low and behold I find this Forum and the wonderful posts herein, with tons of info on baffles! Looks like brilliant minds think alike (cough, cough)

I am overwhelmed by the amount of information on this forum. I found that the dimensions of my stove don't match stoves listed (or I am not looking correctly) so I am wondering which model I have. I have always called it a Momma Bear but I see that it is likely a Grandma Bear (?) Mine is a two square door model, that I bought used in 1981. It measures 25 1/2" across the top plate, 26 1/2" deep including the ash tray and 33 1/2" tall at the back, 27 1/2" in the front. It has angle iron legs (with the feet and I have the screen for the front doors when open) top 8" vent. I have a damper installed in the stove pipe about 20" above the stove. I have some 3/8" steel plate so I will use that for a baffle, maybe do that tomorrow. I like the round baffle suspended below the pipe opening as well but I imagine that the plate baffle would be more efficient, just a guess.

Thanks to all who have contributed to this forum, I am happy to belong.

Tom L.
Hingham, MA

Welcome to the forum - and yes this is the place to be!
Yep - the baby, mamma and papa bear stoves had single doors so easy to tell apart from the double door models. Good luck with the baffle install and be sure to post pics if possible before/after.
So I'm confused does your stove already have the round baffle just below the exit flu or no ? I understand certain stoves had that as original to the stove and others did not. I can't recall if anyone with top exit is running both the round baffle just below the exit together with a smoke shelf 'baffle' horizontal from side to side. If it were me I'd probably try both!

 

[coaly]

Welcome to the Forum Tom;

Yes, you have a Grandma there. Measurements for the box are correct, your height is 3 inches higher than normal. Possibly longer legs?

3/8" shouldn't warp like this 5/16 factory baffle in an XL;


This is far wider than your Grandma. Goldilocks is the same width, and the 5/16 factory baffle stayed straight.

Notice the factory smoke shelf has 2" X 3" notches in the front corners. Not sure of the purpose, but it would allow more heat to the top at the sides, as far as possible from the vent. This was designed during smoke reduction testing, so it must be beneficial. The Goldilocks plate is the same design.
By putting a bend in the plate at the rear and front edge, (so the front and back edge is horizontal) about 1 1/2 inch from the edge, may keep it straight. Probably have to take it to a fabricator with a large enough brake.

The round baffle plate was only in the Honey Bear. That model is about half the size of a Grandma, so a smoke shelf baffle would have taken too much room in the firebox. It's more of a diverter than a baffle.

Here's my latest baffle for a Mama Bear that the owner was rough loading and kept knocking the support bricks out from under it. This 5/16 plate has been in use a season and a half with no warpage.
1 1/2" angle iron welded to the sides will prevent the upright bricks from falling into the fire. I never knocked mine down, but some people aren't careful loading; (Baffle is shown upside down on flat stove top, angle iron is at baffle front edge)




If only the stoves had welds that look like that..........

 

[WeldrDave]

Welcome Tom,
I'm fairly new also to the forum, you'll get some "GREAT" information here. I am currently working on a baby bear doing the excact same thing, Coaly has been extremely helpful and full of Fisher wisdom. Just yesterday I removed my old fire brick, while your stove is down or the brick is in bad shape it's cheap enough to put fresh brick in "and worth it". "Be for warned", have a jackhammer, hand grenade, and large box of bandaids when and if you start the process. my bricks seemed to have welded themselves together and to the sides of the stove. I had to break most of them out with a pry bar and hammer. My baby bear will require a little different application for the baffle that Coaly has been helping me out with, smaller inside. When I'm done I'll get some pictures out, I'm not super computer savvy so I'll get the wife to help out.
Welcome again Tom, this is a great place to learn.

Dave

 

[Mo Par]

Welcome Tom

You can't go wrong with a Fisher. A baffle will put more heat in the room. Since adding a baffle to mine it really throws the heat. As a matter of fact I just checked it, the stack is 290 degrees the lower step on the top's 620 . Nice and toasty.

 

[mark cline]

Hello all, new member here, just joined today. What a fantastic Forum! I have had my Fisher stove for 31 years and recently decided that I would like to decrease the amount of wood cutting/splitting that I do so wanted to increase my stoves efficiency. I thought about the new baffled stoves and sketched up a baffle for my stove, decided to Google it and low and behold I find this Forum and the wonderful posts herein, with tons of info on baffles! Looks like brilliant minds think alike (cough, cough)

I am overwhelmed by the amount of information on this forum. I found that the dimensions of my stove don't match stoves listed (or I am not looking correctly) so I am wondering which model I have. I have always called it a Momma Bear but I see that it is likely a Grandma Bear (?) Mine is a two square door model, that I bought used in 1981. It measures 25 1/2" across the top plate, 26 1/2" deep including the ash tray and 33 1/2" tall at the back, 27 1/2" in the front. It has angle iron legs (with the feet and I have the screen for the front doors when open) top 8" vent. I have a damper installed in the stove pipe about 20" above the stove. I have some 3/8" steel plate so I will use that for a baffle, maybe do that tomorrow. I like the round baffle suspended below the pipe opening as well but I imagine that the plate baffle would be more efficient, just a guess.

Thanks to all who have contributed to this forum, I am happy to belong.

Tom L.
Hingham, MA

I have, I think a Grandma Bear stove like yours but my width of the top plate is 27 1/2". All other measurements are the same minus the ball feet. I bought my stove new in 1982, it was a left over for a few years and I only paid $350 for it . I won't give it up for nothing. It will be going with me ,into to my 2100 sq ft loghome when its closed in this summer.

 

[mark cline]

So this year i finally took some time and built a baffle. Unfortunately I neglected to take pictures as i built the baffle only of the installed unit.
2 pieces of .25" plate 26.5"x8". Overlapped them by about an inch and welded some angle to the one so i could slip fit them together once they were in the fire box. Final plate worked out to be around 26.5"x15". I installed a 2nd row of firebrick in the back of the box to act as a shelf as seen in some other people's setups. Then I took my diamond wheel and cut 2 more bricks on an angle to allow the baffle to prop up inside the box. This leaves the ~2" spacing for proper exhaust venting for the 8" flue.

View attachment 81240View attachment 81241View attachment 81242

Seems to really do the trick!!

View attachment 81243View attachment 81244

Lots of heat pouring from the stove and LESS going up the flue!
So glad I took the time to build one this season!

I like your pictures of the baffle and want to put this 2 piece design in my stove , but I won't weld the 2 pieces together so that I can slide the opening larger or smaller to be able to experiment with the opening. Just curious what the top plate width is on your stove. Mine is a Grandma Bear I believe , with the top plate width of 27 1/2 ". I bought my stove at a stove shop in Buffalo ,NY, so I think they were most likely made in the same shop. I bought it new but did not get any info with it . I have never found a serial # or identifying marks on it.

 

[Jack Fate]

Hi out there looking for some fabrication ideas on a grandpa with rear exit flue. I'm seeing everything but ,then again I can be blind at times ( just ask my wife) we are talking baffle here .

 

[coaly]

If you draw with chalk on the side of the stove, start with a line from the rear just below the outlet pipe. (or from the top of firebrick if there is only one course to set it on. I measure it inside, and transpose the line to the outside so you can get a good idea of plate size. Width is about 1/2" narrower than stove to be able to get it in and out. This can vary with stoves) Angle the line upwards towards the top bend. Smoke space square inch area at top edge of plate varies with draft. Just don't make it smaller than the cross sectional area of the outlet. (50 sq in.) 2 to 3" below the top is fine. The factory original on later stoves was about half that size, since they didn't know how well of a drafting chimney some customers would have.

Here's a pic inside an XL rear vent that shows the plate angle; This was the shape of factory baffle sitting on angle iron. If you bolt or weld short pieces of angle iron on the plate sides, near front, you can stand bricks upright to set the plate on without fear of the larger plate and bricks falling in. I don't have a pic of one inside a Grandpa.

 

[Jack Fate]

If you draw with chalk on the side of the stove, start with a line from the rear just below the outlet pipe. (or from the top of firebrick if there is only one course to set it on. I measure it inside, and transpose the line to the outside so you can get a good idea of plate size. Width is about 1/2" narrower than stove to be able to get it in and out. This can vary with stoves) Angle the line upwards towards the top bend. Smoke space square inch area at top edge of plate varies with draft. Just don't make it smaller than the cross sectional area of the outlet. (50 sq in.) 2 to 3" below the top is fine. The factory original on later stoves was about half that size, since they didn't know how well of a drafting chimney some customers would have.

Here's a pic inside an XL rear vent that shows the plate angle; This was the shape of factory baffle sitting on angle iron. If you bolt or weld short pieces of angle iron on the plate sides, near front, you can stand bricks upright to set the plate on without fear of the larger plate and bricks falling in. I don't have a pic of one inside a Grandpa.

View attachment 89804

View attachment 89805 View attachment 89806

Ok so I did some measurements got 27" interior width so 26 1/2" and measures 16" to the bend at the top from the top of brick supports so 26 1/2' x 12" would give me a 4" gap to the bend maybe a bit less than that that sound reasonable ? 5/16 or 3/8" ?
I see top photo ok but the lower pic I don't get ,are they shown upside down ? don"t understand how it is held at the proper angle. I suppose I can just ad-lib here .but I'd sort of like to understand how that plate with the welded tabs can set at the 45 degre angle that is shown in the XL pic at top. Seems to me thats for a top flue shelf plate baffle 2 fire bricks high ? I understand the baffle at the bottom is not for a granpa stove .
I'm thinking a support from brick tab to baffle

PUZZLED

 

[coaly]

Yes, the flat plates are upside down to show the angle iron welded to the plate. It's 1 1/2" angle iron on 5/16 plate. 3/8 is better for your larger size, but factory used 5/16. (And warped in wider stoves as shown in XL photo) Plate size is fine, factory was only 8". But again they had to err on the small side in case of a poorly drafting chimney to avoid smoke roll in problems with doors open.

If you have one course of bricks around bottom of stove, stand a brick on each side on top of the first row to raise the front edge of plate. I wedge a piece of wood across the two bricks to hold them tight to the stove sides while I set the baffle on top. Angle baffle through door, and set plate level on top of bricks. Then slide it towards the back letting the back drop onto the rear brick ledge. Remove wood wedge holding bricks tight, and you can slide the bricks fore and aft to change the plate angle.
It should sit on the bricks as shown; (no angle iron on plate in photo)


The baffle plate shown rests on a welded tab under the outlet in this Mama Bear. If you don't have anything in your stove to set it on, use the top of the bricks. If you feel this is too low and takes away from loading area, set one brick sideways across the back in center to raise the plate just under the outlet. They cut clean and easy when scored with masonry blade in circular saw.

 

[Jack Fate]

Yes, the flat plates are upside down to show the angle iron welded to the plate. It's 1 1/2" angle iron on 5/16 plate. 3/8 is better for your larger size, but factory used 5/16. (And warped in wider stoves as shown in XL photo) Plate size is fine, factory was only 8". But again they had to err on the small side in case of a poorly drafting chimney to avoid smoke roll in problems with doors open.

If you have one course of bricks around bottom of stove, stand a brick on each side on top of the first row to raise the front edge of plate. I wedge a piece of wood across the two bricks to hold them tight to the stove sides while I set the baffle on top. Angle baffle through door, and set plate level on top of bricks. Then slide it towards the back letting the back drop onto the rear brick ledge. Remove wood wedge holding bricks tight, and you can slide the bricks fore and aft to change the plate angle.
It should sit on the bricks as shown; (no angle iron on plate in photo)
View attachment 89862

The baffle plate shown rests on a welded tab under the outlet in this Mama Bear. If you don't have anything in your stove to set it on, use the top of the bricks. If you feel this is too low and takes away from loading area, set one brick sideways across the back in center to raise the plate just under the outlet. They cut clean and easy when scored with masonry blade in circular saw.

Think I'm going to bolt baffle to the angle iron firebrick supports with some flat stock & slot flat stock for adjustability . Don't need to weld then but do have to drill fire brick supports & baffle plate. Welding is a hassle but not impossiable for me
Thanks Coaly

 

[KristenGood]

Hi Everyone, I have a '76 Grandpa Bear and was looking for help on dimensions for the interior baffle size. Unfortunately its 3 hours away, and I can not measure! I am interested on doing the steel plate and resting it on fire brick. I have a top vent. Any and all help would be appreciated! Thanks!

 

[coaly]

I would measure it. I could tell you what it's supposed to be, or give you the dimensions of mine, and yours could be different than both. Even the flue collar could protrude farther down inside than normal changing the angle. Every fabricator came up with ways they liked to do things, and many vary from the prints slightly, so there's no one size fits all.
You want 5/16 thick steel plate, one piece. About 1/2 inch shorter than across the inside measurement. When done, you should not be able to look straight down the outlet and see the stove bottom. The flames should be directed in front of the flue collar that should stick down inside the stove causing flames to hit the stove top instead of the damper plate in the pipe.

 

[KristenGood]

Hi Coaly, thanks for the information! I was hoping you had the magic number. I guess I will drive up and measure to make sure it is right. I did notice on some of the pictures, that some people have the steel plate with the center jutting out a bit. I am assuming that is where the flue collar comes into the stove, is that needed or can I just go with a straight piece? Sorry for all the questions, just want to do it right. This forum has been amazing, a wealth of information. I did buy the stove bright paint and we are planning on painting it next time we head up to our cabin. Just curious, where in NE PA are you? Our cabin is in Tioga. That is where our stove is! Thanks!

 

[coaly]

One piece plate just under the outlet collar clears everything.
The Poconos; Monroe County.

 

[Captain Hornet]

Well okay, I finely got around to installing my baffle. It looks exactly like the one you show. Installed into my Mama insert. I made it from 3/8 plate and support it with bricks. I have wanted to do this for several years but had problems with the whole concept. First, the insert is lined to the roof with a 6 in stainless liner but the flue is only 12 feet long, so my draft is not the best. I was concerned about smoking in the house when I open the door. Also, my stove makes a good bit of creosote and I have to scrub it all out or it plugs up. every 45 days or so. To be fair the most creosote is in the last top 6 inches of the pipe and I have installed a large free flow cap without screen to help the draft. My baffle sticks out 13 inches from the sloped back of the stove and it is a good tight installation. Last years I have used way more wood than I should so this well help but I'm worried about making more creosote with a weaker draft. I really hope you guys know what you're talking about, Time well tell. David

 

[pen]

Well okay, I finely got around to installing my baffle. It looks exactly like the one you show. Installed into my Mama insert. I made it from 3/8 plate and support it with bricks. I have wanted to do this for several years but had problems with the whole concept. First, the insert is lined to the roof with a 6 in stainless liner but the flue is only 12 feet long, so my draft is not the best. I was concerned about smoking in the house when I open the door. Also, my stove makes a good bit of creosote and I have to scrub it all out or it plugs up. every 45 days or so. To be fair the most creosote is in the last top 6 inches of the pipe and I have installed a large free flow cap without screen to help the draft. My baffle sticks out 13 inches from the sloped back of the stove and it is a good tight installation. Last years I have used way more wood than I should so this well help but I'm worried about making more creosote with a weaker draft. I really hope you guys know what you're talking about, Time well tell. David

Did you insulate that liner? Is the chimney on the exterior or interior of the home?

If it's uninsulated, and an exterior chimney, those are two things against you. However, w/ a stove of this style and truly seasoned wood, so long as you aren't snuffing the stove down too low for 'night' or 'while at work' or 'to make it last a long time when it's not too cold' type burns, there's no reason you should be getting much build up.

Keep us posted!

pen

 

[Captain Hornet]

Yes, the chimney is a huge brick outside one on the end of the house, The origional flue was a 5 by 7 taracotta pipe and I had to ovel the 6 inch stainless liner. It was a absolute monster to get down the taracotta but I finely really forced it. I packed the old funnel and smoke shelf with fibreglass but there is no insulation on the pipe for the last 8 feet. There isn't room anyway. The lower blockoff plate is rivited in. The top plate is stainless and has a real good perminate leak proof seal. It would destroy it to attempt to remove it just to pore a little cat litter down between the old taracotta and the new liner. Actually I don't think I would gain much if I tried that because there is nothing to keep it from leaking down into the old smoke shelf. So I guess it's as good as it gets. We'll see how much improvement I get if any but if I cut down on my wood comsumption it would be a improvement. David

 

[rowerwet]

After a couple more fire I would confirm everything I said above, and add that the stove-pipe temperature has become more stable. It is now far less critical to stand-by ready to choke the input air as the stove-pipe temperature gets too high. The lower stove-pipe temperature does not try to "run away" like it did from flames blasting up the flue. The stove just runs better with the baffle installed! Here's where the temperature gauge is on the stove-pipe:
View attachment 77441

thanks for the pictures, I was about to ask about a firebrick baffle when I noticed your posts, my grandpa bear will get the same.
How much of a gap from the front/top of the stove is there from the front of the baffle?

 

[Captain Hornet]

OKAY, I admit it, Coaly was right. I have had fires for the last three days with my new baffle. I changed the design a little bit and made it come out 16inches from the back of the stove. There is no smoking into the house with the door open so I am pleased. In the past when the stove would start to smoke it was telling me that it was time to brush out the flue. I do not think that there is more heat than before but it's more even without the hot and cold cycles. I notice that the stove top does not get as hot as before. I'm just going to live with this and see how it does after a while, Creosote and heating report to follow later. Thanks Coaly, David

 

[rowerwet]

first fire with the new fire brick baffle, amazed at how fast the lower top of the stove heated up

 

[Jack Fate]

Currently running Fisher Grandpa with baffle (as instructed) & some additional fire brick& large slab of soap stone. So far all is well .Performance seems improved ,more of a steady, stable, heat with improved efficiency .

Only used this stove 10-20 days a year before, may use it more often now .

Thanks all ,very much recommend the baffle mod

Cheers

 

[rowerwet]

been running the stove a few weeks now with a fire brick baffle. I just bolted four sticks of angle iron at the corners, no welding.
the first thing we noticed, it takes much less time to get heat out of the lower top of the stove (this becomes the hotest part) we get more heat out of the stove with a low fire than we did before the baffle with a roaring pile of wood.
Even down into the 20's we have to keep the draft closed down much more than before, many times only leaving one open, as the house becomes too hot (over 70).
Even the heat from the coals left after letting the fire go out this morning seems to last much longer.
thank you! Coaly!

 

[rowerwet]

the advantage of the firebrick baffle is simple, the stoves (at least mine) has been sized around fitting firebricks without cutting any. My stove is 6 bricks wide across the back, my baffle frame supports six bricks across it holding them horizontally.
unlike getting plate steel, and getting steel plate bent or welded, any hardware store sells angle iron, hacksaws, and drill bits. Fire brick is cheap, mine was $3.50 each at tractor supply.
Anybody can run a hacksaw and a drill. measure the stove, cut the angle iron to length, drill a hole at each corner big enough for a bolt, assemble the angle iron frame in place in the stove, install the bricks.
the front stick of angle iron is suppported on each end by the fire bricks lining the sides of the fire box, with the lip facing up.
the two sticks on the sides have the lip facing down and are as long as the fire bricks.
The rear stick is supported on the lip below the stove pipe, with the lip facing up.
I also added another level of fire brick to the back of the stove to fill the gap at the back of the baffle.

 

[Dave K]

I just spoke to a wood stove place in my area and they told me that I shouldn't install a baffle plate in an old Fisher because I would probably end up warping the stove. I said "you mean I may warp the baffle plate?" and he said "no, the whole stove may warp". Anybody have any thoughts on this?