Papa Bear Baffle Install

Sighlence

New Member
Sep 8, 2020
6
Upstate NY
I just finished doing this to my Papa bear. Measured out to 17" x 8" using 1/4" steel plate. I just hope it doesn't affect the draft. Being that i have three elbows by the time it reaches the chimney, my draft isn't the greatest. I'm most worried about getting blow back due to cooler flue temps. Can anyone tell me what the best temp to keep the flue pipe at? I can always take it back out if things don't go as planned.

baffle (2).jpg fisher.jpg
 

Sighlence

New Member
Sep 8, 2020
6
Upstate NY
any pictures of the flue with the 3 elbows
Well, it's basically 2 from stove to wall, then straight pipe thru the wall to the chimney. I guess i was counting wall pipe to chimney as the third(angle), although they isn't an elbow in place. I can hear a pretty good draft before i start it up, but there are times when i'll get blowback(puffs) thoughout the burn season. I'm thinking that might be from not keeping the flue pipe warm enough. When i close it down for the night it usually stays at about 200/210 degrees. I have the thermometer halfway up the pipe. During the day i rarely keep it above 300 degrees. I'm kinda worried it'll be harder to keep flue temps up with the baffle in place. However, the idea of more burn (less smoke) and less creosote buildup is the main appeal.
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,179
NE PA
The object is keeping flue gas temp above 250* to the top. This is the critical temperature where water vapor condenses and wets walls allowing smoke particles to stick. This forms creosote.

A surface mount thermometer reads about 1/2 the actual inside exhaust temp. By the time it cools as it rises, you’re back to about what the thermometer reads, hence the color zones for an approximate correct temperature. For a more accurate temp, figure the temperature drop to the top. Factors being masonry, insulated, inside or outside chimney. Another factor is chimney diameter. A 6 inch pipe increased to 8 inch chimney drops the exhaust temperature by 1/2.
If you used to use a pipe damper to slow chimney, the baffle adds a small amount of resistance, so less damper is needed. As long as the opening the exhaust travels is the same square inch area as chimney, you should be fine.

Since you are familiar with your stove and set up, let us know what you think about being more controllable and a higher heat output from the front of the stove. You should notice far less smoke before it even comes up to temp. That is an indication you will have less particles to form creosote.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
23,986
central pa
I would like to say thank you for the baffle specs. I found a mama bear on market place cheap. So i had a weilder cut the top and weild two brackets to support the baffle plate. Good thing, i can take the plate out if i desire. I used your exact measurements. I took out my epa stove because of cost of fire brick and combustion box. Now i have a life time stove. A shorter burn time, but cheaper to maintain!!!!!
Just out of curiosity what was the modern stove you replaced?
 

Sighlence

New Member
Sep 8, 2020
6
Upstate NY
The object is keeping flue gas temp above 250* to the top. This is the critical temperature where water vapor condenses and wets walls allowing smoke particles to stick. This forms creosote.

A surface mount thermometer reads about 1/2 the actual inside exhaust temp. By the time it cools as it rises, you’re back to about what the thermometer reads, hence the color zones for an approximate correct temperature. For a more accurate temp, figure the temperature drop to the top. Factors being masonry, insulated, inside or outside chimney. Another factor is chimney diameter. A 6 inch pipe increased to 8 inch chimney drops the exhaust temperature by 1/2.
If you used to use a pipe damper to slow chimney, the baffle adds a small amount of resistance, so less damper is needed. As long as the opening the exhaust travels is the same square inch area as chimney, you should be fine.

Since you are familiar with your stove and set up, let us know what you think about being more controllable and a higher heat output from the front of the stove. You should notice far less smoke before it even comes up to temp. That is an indication you will have less particles to form creosote.
Thanks for the reply, coaly. I have never used a pipe damper with this setup, which i have been using for a good 15+ years. Most of my creosote buildup is between the stove elbow and the exit of the wall pipe into the chimney. I have always been hesitant to open it up too much because the pipe thermometer goes into the red from the flame going straight into, and up the pipe. I am hopeful this baffle will allow me to open it up a lot more, thus creating a cleaner burn with less creosote buildup. I use 6" pipe all the way, and the gap between the baffle and top of the stove is about 3" all the way across.
 
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Fat wood

New Member
Sep 12, 2020
14
Va.
Just out of curiosity what was the modern stove you replaced?
For 9 yrs I heated with a Harman Oakwood. Nice stove, long burn time. The hardware store where I bought it said," if you burn everyday this isn't the stove for you." Are you kidding me, after I paid $2000.That was in 2009. So its in the basement needing a new fire box again for over $400. Now I have a lifetime stove with my Fisher.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,986
central pa
For 9 yrs I heated with a Harman Oakwood. Nice stove, long burn time. The hardware store where I bought it said," if you burn everyday this isn't the stove for you." Are you kidding me, after I paid $2000.That was in 2009. So its in the basement needing a new fire box again for over $400. Now I have a lifetime stove with my Fisher.
Yeah harman's like that were about the least durable stoves on the market. Rivaled only by Vermont castings. There are many other new stoves on the market that will perform better than the harman. And far better than the fisher while taking little to no maintenance. Not saying there is anything wrong with using a fisher. Just that the pos stove you had is not a good representation of other modern stoves.
 
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Sighlence

New Member
Sep 8, 2020
6
Upstate NY
Yeah harman's like that were about the least durable stoves on the market. Rivaled only by Vermont castings. There are many other new stoves on the market that will perform better than the harman. And far better than the fisher while taking little to no maintenance. Not saying there is anything wrong with using a fisher. Just that the pos stove you had is not a good representation of other modern stoves.
I don't know how one could get more maintenance free than a Fisher. I have been using mine since 1989 and it has shown zero wear
I would like to say thank you for the baffle specs. I found a mama bear on market place cheap. So i had a weilder cut the top and weild two brackets to support the baffle plate. Good thing, i can take the plate out if i desire. I used your exact measurements. I took out my epa stove because of cost of fire brick and combustion box. Now i have a life time stove. A shorter burn time, but cheaper to maintain!!!!!
I had a hard enough time getting my baffle in place, can't imagine having enough room to actually weld something in there!
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,986
central pa
I don't know how one could get more maintenance free than a Fisher. I have been using mine since 1989 and it has shown zero wear


I had a hard enough time getting my baffle in place, can't imagine having enough room to actually weld something in there!
I never said modern stoves were more maintenance free than a fisher. Just that good modern ones out perform stuff like fishers in just about every way. And good ones don't take much maintenance at all. What they do take is easily offset by less wood use and less chimney maintenance
 

Fat wood

New Member
Sep 12, 2020
14
Va.
I don't know how one could get more maintenance free than a Fisher. I have been using mine since 1989 and it has shown zero wear


I had a hard enough time getting my baffle in place, can't imagine having enough room to actually weld something in there!
I had a good wielder do it!! I tried to talk him into making a stove, He said cost and time its not worth it. Heck you barely see the wield on the outside.
 
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Sighlence

New Member
Sep 8, 2020
6
Upstate NY
I had a good wielder do it!! I tried to talk him into making a stove, He said cost and time its not worth it. Heck you barely see the wield on the outside.
Good welder indeed (and lots of patience!). I had to have my wife hold the plate in place with a broom stick while i slid the fire brick underneath it.
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,179
NE PA
I set the firebrick on edge at front of baffle plate. Cut a piece of wood longer than the firebox width. Wedge it between the bricks across the firebox to hold them in place. Then set the baffle on top. Push the baffle to the rear until it tilts down at the rear and falls into place. Have installed with a stove with glowing coals and welder gloves.

The angle tilting upward toward lower bend is important. The flatter, the more flame impingement that reduces flame tip temperature. The higher the angle, the faster the flow and less resistance. I set the height at front so the opening the exhaust travels through is the same square inch size as chimney flue square inch. That is the minimum opening, More resistance from elbows, horizontal runs and excessive connector pipe configurations requires a larger opening above baffle to let more heat escape. Pushing bricks fire and aft raises and lowers plate to adjust for each venting system.

If supports are welded in place, shim the front of baffle higher as necessary to adjust. You may have to cut firebrick in wedge shape to raise it.
 
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Sighlence

New Member
Sep 8, 2020
6
Upstate NY
I set the firebrick on edge at front of baffle plate. Cut a piece of wood longer than the firebox width. Wedge it between the bricks across the firebox to hold them in place. Then set the baffle on top. Push the baffle to the rear until it tilts down at the rear and falls into place. Have installed with a stove with glowing coals and welder gloves.

The angle tilting upward toward lower bend is important. The flatter, the more flame impingement that reduces flame tip temperature. The higher the angle, the faster the flow and less resistance. I set the height at front so the opening the exhaust travels through is the same square inch size as chimney flue square inch. That is the minimum opening, More resistance from elbows, horizontal runs and excessive connector pipe configurations requires a larger opening above baffle to let more heat escape. Pushing bricks fire and aft raises and lowers plate to adjust for each venting system.

If supports are welded in place, shim the front of baffle higher as necessary to adjust. You may have to cut firebrick in wedge shape to raise it.
This is why i am starting with a 3" opening. The nighttime temps here haven't been too bad (40 degrees) so i have held off doing a test burn. I figure i can adjust if need be, but i'm thinking that should be the sweet spot for my set-up.
 

Dr_1400

New Member
Jan 25, 2021
6
Adirondacks
This is why i am starting with a 3" opening. The nighttime temps here haven't been too bad (40 degrees) so i have held off doing a test burn. I figure i can adjust if need be, but i'm thinking that should be the sweet spot for my set-up.
Sighlence, I'm curious how your Papa Bear baffle is working out for you. I'm planning one of my own and reading old threads. I'm measuring my setup this week and need to decide on the length (front to back) of my plate. At 8 inches you must have a fairly steep upward angle on that baffle plate?
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,179
NE PA
Sighlence, I'm curious how your Papa Bear baffle is working out for you. I'm planning one of my own and reading old threads. I'm measuring my setup this week and need to decide on the length (front to back) of my plate. At 8 inches you must have a fairly steep upward angle on that baffle plate?
8 inches won't get you near the top bend to be able to get your smoke space (the square inch area smoke travels through) down to what you want.

Measuring a very early Papa with side vent, (one of the first made with 3 piece top and flat door before trees) I get approximately 18 inches from rear to the top bend, and 24 inches to midway of the lower front top plate.

A newer Baby Bear measures 13 inches from back to the top bend, and 17 inches to midway of the lower top plate.

The factory baffle in a Honey Bear which is a Fireplace Series having much smaller tops and wider than it is deep, is 10 inches from back to front, 18 inches wide. The upper top measures 10 inches rear to bend radius. This gives about 2 inches from front baffle edge to the bend in top. This stove requires straight up pipe and insulated 6 inch chimney. They could have made the baffle larger, but err on the side of caution if someone installs with a less than optimal pipe and chimney configuration.

Since stoves were made with top, side and rear outlets, single brick course, or optional double course, varying width between a few fabricators, I never give exact measurements because you're always going to find variations. Then guesstimate your specific needs for the heat you need to leave up the chimney for pipe configuration, chimney size, type and height. It's easy to lower plate a bit at front to allow more heat out, (as long as you have enough angle of plate). Worst case scenario is cut the plate an inch shorter, or cut a saw tooth pattern across the front to increase square inch opening area. This may create wanted turbulence above the plate as well. I've wondered about a slight bend across the front plate, so the edge was horizontal to roll the smoke and exhaust gasses above baffle. A slight change could make a big improvement like the notches cut into the side edge at front on the factory baffle tested by Fisher.
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,179
NE PA
I never tried it, but I would think a piece of cement board used as a temporary baffle plate would give you an idea of how well the smoke evacuates and the size allowable to prevent smoke roll in. I don't know how may test fires it will withstand, but could ease your mind if it will cause smoke roll in issues.
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,179
NE PA
If your wife comes home wondering what happened to the toilet tank lid, tell her it was removed to humidify the air and she can have it back in the spring. ::-)
 

Dr_1400

New Member
Jan 25, 2021
6
Adirondacks
If your wife comes home wondering what happened to the toilet tank lid, tell her it was removed to humidify the air and she can have it back in the spring. ::-)
I won't be going there!

Cement board is a great idea for test plates, thank you. My only remaining confusion on a Coaly-approved baffle plate is which part of the angled top to aim the baffle at. Originally I thought the lower bend, now thinking top bend.

In the crude picture, am I aiming for 1 or 2?


54A75A55-D67A-469A-9CB4-C3E53BC8ED9C.jpeg
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,179
NE PA
Bottom bend. That's why I gave minimum to bend, or midway across lower top for the maximum you would want. Newer stoves are half as deep, load sideways and the baffle comes up within inches of the door. That would be a Fireplace Series type Fisher, wider than deep. A deep stove, the shape of firewood logs like a Box stove just makes sense.

I'd cut a test plate to come toward the front, midway of the lower top first. If it smokes when opening door slowly, cut it down to just forward of the lower bend. If still a problem, cut to just at the bend.
 

Dr_1400

New Member
Jan 25, 2021
6
Adirondacks
Bottom bend. That's why I gave minimum to bend, or midway across lower top for the maximum you would want. Newer stoves are half as deep, load sideways and the baffle comes up within inches of the door. That would be a Fireplace Series type Fisher, wider than deep. A deep stove, the shape of firewood logs like a Box stove just makes sense.

I'd cut a test plate to come toward the front, midway of the lower top first. If it smokes when opening door slowly, cut it down to just forward of the lower bend. If still a problem, cut to just at the bend.
That makes a lot of sense, thank you. I was thinking much shorter. I can see how those plates become heavy.