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

[Jack Fate]

well lets see, last year I decided to try to load n/s a tight rack . Well I'll NEVER do that again . We got HOT like 900 + stove top temp . I figure if this old Fisher was gonna warp it would have done it then . ALSO the baffle is floating in place (not welded wall to wall) so how? .( this over fire was done before baffle instillation ) The baffle does reduce draft/draw so you MAY need to crack door/or open dampers first Before opening doors on stove .Or you may get a bit of smoke in the house(wives as a general rule don't like this )
got two quotes come to mind here
"An expert knows is someone who knows no more than you, but is from out of town"
Mark Twain
the other I can't repeat

Cheers

 

[rowerwet]

did they offer a "great deal" on a new stove to replace your fisher? I've never seen or heard of a fisher being warped during an over fire, or even one heard of one reaching the glowing red stage.
I've been heating for a few weeks with a baffle now, I don't know how the stove could be damaged by it.
Smoke is no more of an issue than before the baffle, if you don't open the damper it will smoke, open the damper to throw in wood, no smoke.

 

[Dave K]

okay, thanks guys!

 

[coaly]

Dave, Here is where the hottest part is around the outlet with no baffle.



I've got pictures of a few with cracks around the outlet pipe that needed a baffle ! That is where they fail (fatigue cracks) and the baffle directs this heat to the stove top which is thicker (5/16) instead of the thinner 1/4" stove body.



Goldilocks, Honey Bear, Grandma and Grandpa III had a factory smoke shelf baffle and I've never seen one with any heat associated damage from the baffle.

Warp the whole stove huh? Only the nuclear powered baffles can do that.

 

[BigZ_87]

How well would one these baffles work inside a Fisher Fireplace Insert?

If so, do you have any ideas on the dimensions for the baffle?

 

[coaly]

This thread should help; check out the drawing in post #9;

https://www.hearth.com/talk/threads/cant-seem-to-figure-out.119184/#post-1598093

 

[Hubcap]

Dave, Here is where the hottest part is around the outlet with no baffle.

View attachment 118404

I've got pictures of a few with cracks around the outlet pipe that needed a baffle ! That is where they fail (fatigue cracks) and the baffle directs this heat to the stove top which is thicker (5/16) instead of the thinner 1/4" stove body.

View attachment 118414 View attachment 118415

Goldilocks, Honey Bear, Grandma and Grandpa III had a factory smoke shelf baffle and I've never seen one with any heat associated damage from the baffle.

Warp the whole stove huh? Only the nuclear powered baffles can do that.

This is similar to my stove. But I see no cracks just warping around the bottom of outlet pipe. Can I straighten it or just live with it?

 

[coaly]

Wouldn't worry about it. It may even go back flatter with even heating.

 

[Hubcap]

Wouldn't worry about it. It may even go back flatter with even heating.

Ok. Sorry about torch question. I just seen that you told me not to worry. I was crushed when I seen it though, because the rest of the stove is excellent. Paid $350 Number in door said 599?

 

[yrneh]

This thread just what I need to fix my baby bear clone (woodland stove). The bottom of the L shaped flue is burned out so a plate steel baffle set on a couple of side standing fire bricks will really do the trick.

 

[yrneh]

Well the Woodland stove its not as small as a baby bear but it isn't as big as a mama bear, but the simple baffle works just as good. You can see through the top of the six inch flue that the elbow is really burned out. The 5/16 baffle rests very good on two half bricks and leaves me 2 1/4 inches of gap across the 15 inch width of the stove so I have about 5 1/4 square inches more space than in the six inch flue. I believe this baffle will make the stove better than it was when it was when it was brand new.

 

[Fisher Fired]

Hi all, new to this forum and figured I'd share my experience after reading lots of good info. Any way, I just currently got my hands on a real nice fisher grandma bear stove. Been running it for about a month now and recently just installed a baffle and door gaskets. I know these stoves don't require any gaskets but I was getting a lot of leakage around the doors. Now that these upgrades were installed I have noticed a much longer burn time and a lot less smoke. Now I have to leave the intakes just a tad open cause if there all the way shut the fire will just about go out. I used the flat tape style gasket in the channel on the stove. My baffle is 5/16" x 22 1/2 " x 10 " have a 2 1/2 " gap just a bit more surface area than the 8 " exhaust. We'll see how it goes. So far so good. Thanks for all the great info.

 

[coaly]

Thanks for sharing that info and plate size. The first time I lit mine with the baffle I was surprised by how much it reduced smoke too. I was only trying to drive the heat forward instead of cooking the elbow on the back........... I went outside before the stove was up to temperature and it already had a cleaner stack. It used to smoke until all the way up to temp. That was in a Mama Bear, and I realized the reason for the "Smoke Shelf Baffle" in the later double door stoves was due to the smoke regulations getting stricter in stages. Made sense that it would reduce smoke too....... I've been experimenting with secondary combustion and wonder if the notches cut out on the sides at front edge were to raise baffle surface temperature?? Metal can't cool itself on the edges, so that gives it more edge area to possibly ignite more smoke particles that come in contact with it. I toyed with the idea of a saw tooth edged baffle to gain edge length, but it takes an opacity meter and particle measurement to verify how much improvement. I'm sure research and development tried everything they knew to reduce smoke, and now with the advent of secondary air at the top, obviously that was the solution.

All the double door baffles were shaped like this. That is my own and as flat as the day it was made in 1984. (5/16) I didn't clean it for the picture - just the way it burned. Top vent Goldilocks which is Grandma width. Maybe they just wanted to get flames to the stove top in the raised rear section, or flame to ignite smoke when conditions were right. I'm sure it was engineered for a purpose. Any baffle is far better than none as you found out........

If they don't almost go out when the draft caps are closed the way yours does now, you pretty much can only gasket it the way you did if the doors and iron seal is clean. It doesn't take much of a bow or bend in the channel iron, or high spot on the door to keep it from closing flat. Short of a milling machine, it's far easier to gasket the channel. The door drawings allow for removal up to 0.050" and state "If door seals are surfaced align hinge hole after surfacing". So they were aware of getting a better seal machining the cast door and iron channel. I've never seen one machined and don't know if any fabricators did.

Is your stove a rear or top vented model?

 

[Fisher Fired]

Hi Coaly thanks for the reply. I have the top vented model.

 

[coaly]

Dave;
It should look just like the one pictured above. That is factory with angle iron welded to the sides. The bricks you set it on will vary depending on if there is a second brick course in the stove. Early in the thread I pictured angle iron welded to a plate to prevent side support bricks from falling inward if you don't have the second course and need to place bricks on the retainers to support it.

And people with single door stoves would love to watch their fire...... That's the efficiency trade off having your fireplace stove. A deep stove with 6 inch pipe and flue is the answer to longer burns. (once you're sure there are no air leaks at door seals and chimney is sized / insulated correctly) BTW I don't see a damper in your avatar, I assume you have one in the vent pipe? I always ended up with too many coals and charcoal in the back after a few days burning 24/7. I would have to open it up and get the pile flaming to get rid if it for room to load during real cold weather. I always remove a little ash from the front where it burns out in the morning and rake some of the pile ahead. Close damper and air almost fully for the day, and by 3 PM remove any ash from the front and rake ahead to reload. Open air and damper and it takes right off. Every few days there is enough coals and charcoal to do that. Since that is our only heat source, I try to burn the coal pile down on warmer or at least sunny days since it won't heat like a load of wood when full of coals. I remove a little ash each day to prevent letting it go out to clean ash.

 

[Mule skinner]

I'm in the process of installing a 21' 6" dia. Ventis for my ~78 Grandma straight up thru the roof near the peak. 4'DW stovepipe no bends. Putting in a baffle and have a few questions...1) can I go with 28sq" or stay with 50sq"? 2) Is the goal to direct the heat to the lower or upper top? 3) Are the notches in the front corners 2"×3"w or 3"×2"wide? 4) When referring to bending front and back edges, should they bend up or down? Thanks for all the wealth of knowledge from all!

 

[coaly]

Welcome to the Forum Mule !

Start with the 28, depending on draft you can always drop the front slightly to increase if needed.

Aim for the lower bend in the top. You should be measuring the distance for square inch vent space between front of plate and bend.

If you notch it, the factory cut was 3 inches from stove side towards stove center.
2 inches in from front edge.



I've never bent one, but it would be bent upwards at the back to contact the stove back on a 90* angle and bent down on the front to have a horizontal lip facing forward.

 

[Tamati]

Here's the 5/16" thick plate that is still in my double door Goldilocks. They were all top vented. Plate is flat and clean as new. Just sets on angle iron side brackets. I purchased this stove new in January 1985 and have used it every season until this year ! Didn't overheat it too many times, but it's well used. The plate in a Mama or Papa is half this size, so it should stay like new. I debated on using 1/4", but figured Fisher used 5/16 for a reason. I'm sure they would have used something cheaper than the thicker top plate material if they could.
This is the first year for the Mama Bear in the middle of the kitchen where the Goldilocks has been. Goldi has a double heat shield plate on the back for reduced clearance to walls, and I always had it face away from the fridge, so this cold side didn't affect the fridge temps. First thing this fall with the new stove was milk going sour in the door ! Things in the fridge seemed cold, but a fresh half gallon of milk went bad in 2 days. I realized the heat radiating towards the back at the elbow had to be the problem. The plate on a 45* angle directs this intense heat towards the stove top, and no more milk issue. This has to make a tremendous difference in loss up the stack as well. The first thing I noticed firing it with no baffle, was a lot more smoke than the baffled Goldilocks. I see where the term smoke dragon came from. It was bad. Now it's comparable in smoke to the Goldilocks. I never had much smoke, and cleaned the chimney mid season "need it or not". We'll see if creosote formation stays the same.

Hi
I just purchased a baby bear. It has a top vent. Needs some work. One thing i want to do is put in a baffle. I like the idea of the plate as in this thread compared to the one used on your honey bear mentioned just past this thread. Could you give advise?

 

[coaly]

That's what you want to do. Depends on if you have a single course of brick or double that goes higher in the back. The chimney plays an important part as well. You'll need a 6 inch insulated flue to be compatible with it baffled correctly. The larger the chimney, the more heat you need to leave up. Keep that in mind when setting the smoke space (exhaust outlet space above baffle edge) and angle.

 

[Tamati]

That's what you want to do. Depends on if you have a single course of brick or double that goes higher in the back. The chimney plays an important part as well. You'll need a 6 inch insulated flue to be compatible with it baffled correctly. The larger the chimney, the more heat you need to leave up. Keep that in mind when setting the smoke space (exhaust outlet space above baffle edge) and angle.

Greetings Coaly from the far south. Happened apon this site a week ago and have been reading bits and pieces with interest since. My vent size is 150mm which is 5.9 inches. (We use metric in NZ) Do you have dimensions that i can use? I want to weld in the baffle so need to get a template that will work first time.

 

[coaly]

Greetings Tamati ! You're reading a lot because it's always raining down there! I see a soggy spring on it's way.
Simply take a piece of cardboard and cut to trial size until you get exactly what you want. You will notice the angle changes the opening, so the lower the baffle, the longer it needs to be for the correct "smoke space" or opening for exhaust. If you weld angle iron onto the sides and set the baffle plate on it, you can adjust it with shims or adjustable bolts in front to raise it. Every chimney is different, and the baffle needs to be adjusted for your draft. An optimum insulated chimney with the exact same size flue all the way up as the outlet size would require the same square mm opening as inside outlet. Lesser drafting with a larger diameter or no insulated flue requires more opening above baffle. So start low with larger opening and raise with set bolts to no less than the same opening in square mm as outlet. You want to be able to fine tune it for your fuel and chimney.

The older stoves measured the vent pipe Outside Diameter. Ours would be 152.4 OD.

 

[Tamati]

Greetings Tamati ! You're reading a lot because it's always raining down there! I see a soggy spring on it's way.
Simply take a piece of cardboard and cut to trial size until you get exactly what you want. You will notice the angle changes the opening, so the lower the baffle, the longer it needs to be for the correct "smoke space" or opening for exhaust. If you weld angle iron onto the sides and set the baffle plate on it, you can adjust it with shims or adjustable bolts in front to raise it. Every chimney is different, and the baffle needs to be adjusted for your draft. An optimum insulated chimney with the exact same size flue all the way up as the outlet size would require the same square mm opening as inside outlet. Lesser drafting with a larger diameter or no insulated flue requires more opening above baffle. So start low with larger opening and raise with set bolts to no less than the same opening in square mm as outlet. You want to be able to fine tune it for your fuel and chimney.

The older stoves measured the vent pipe Outside Diameter. Ours would be 152.4 OD.

Ok thanks Coaly. That gives me a good starting point

 

[Turner87]

I built one for my momma bear, I have it set on the back shelf. Was wondering if yours is all the way against the back wall or is there a gap? Mine has a gap it don't slide all the way under the outlet

 

[coaly]

Mine has a gap at the back too. You can cut a notch for a better fit around the pipe if you don't think you want much leakage up the pipe. I have a lot of single wall to the peak with cathedral ceiling so I know I need more heat left up. If you have double wall pipe and insulated chimney you could retain more heat in the stove since it would not be needed up the stack.

 

[Victy]

Hello, I just got a Mama Bear and was looking at the Baffle Plates, My stove has the flue coming out of the left hand side instead of back or top. Any ideas on design?? Thanks!!