FISHER Grandma and Grandpa Bear Details (Fireplace Series)

coaly · Aug 3, 2013

Yes, triple wall is the required Class A chimney. (Dura Vent) There are other brands that use a dense insulation packed between only two walls. They are a smaller outside diameter, but heavy. As long as it's rated Class A all fuel.
Pipe before that is considered connector pipe. Older triple wall used an air space between the three pipes. Now the inner stainless liner is wraped with insulation keeping the inner flue hotter. The older style cooled so well to keep the outside cold, that they were difficult to keep the inside hot enough. As long as you have 18" to a combustible, you're OK with single wall pipe. Double wall pipe allows you to leave less heat up the flue, radiating more from the stove with less fuel burned. The object is to keep the entire chimney above the condensing point using the least amount of fuel. (250* f )That is easier accomplished with double wall.
The use of a magnetic thermometer just before the chimney will give you an idea what you're putting into it.
You should have a manual damper as close to the stove as possible.

EddieOne · Aug 3, 2013

Gotcha. Thats my plan for the chimney. I'm a little unclear about the design of the baffle plate on the firebrick, would you mind posting a pic or sketch of it for the top exit?

She's coming along nicely. I was going to finish it with satin black, but kind of like the rust free patina...

coaly · Aug 3, 2013

Later stoves had 1 1/2" angle iron welded on an angle for a shelf to set the plate on. I've found it easy to set the plate on top of the rear brick retainer and prop it up with a brick (on top of the side brick retainers) on each side. Angle the front edge of baffle upwards, towards the bend in the top plate. Sliding the 2 bricks at the sides fore and aft adjusts the plate on a steeper angle. As long as you're careful loading and don't knock the bricks out, it seems to stay in place fine. If you want to make it more solid, weld or bolt angle iron pieces onto the plate to act as vertical side plates to keep the upright bricks standing on edge firmly.

Factory smoke shelf baffle in top vent with baffle on angle iron brackets.

Angle iron I added to homemade baffle to keep side prop bricks standing against stove sides. They could be bolted to plate if you don't have welder.

Keep the angle iron towards the front of plate, it will only set on the corners of bricks. Yours won't have the welded on "shelf" in the back that this one sits on;
If you want the back of plate higher than sitting on the brick retainers, (as shown in first pic above, to allow higher wood load under baffle) you can add a piece of angle iron across the back like the sides. Place a brick on edge, or cut one lengthwise in half, centered across the back to set it on. The angle iron will keep the rear brick tight against the stove back just like the sides. Firebricks snap clean and easy with a scored line using a masonry blade in a circular saw. They are quite soft compared to red brick or stone.

Hint; I've learned to wedge a piece of wood between the upright standing bricks to hold them tight. Then angle the baffle plate through the door and set the baffle plate (flat - horizontal) on top of them. By sliding the plate to the rear, it drops down on the rear shelf and is in place. Have done a few with a stove full of embers wearing welding gloves.

coaly · Aug 3, 2013

Your stove painted black, as original.

After painting, you can simply polish draft cap edges with scotch brite for this classy look.

Most just play with high temp paint

Or send the doors out for nickel plating. This one being the ultimate courtesy of Finest Fishers.

EddieOne · Aug 3, 2013

Thanks again Coaly, very helpful info. I'm really liking the older patina on this stove, so will probably keep it as is. But I already purchased the paint, so maybe I'll paint it next year, we'll see. I will be welding the baffle in with angle iron myself, so thanks a ton for the images and explanation. My right door says 5 and the left has a 4, any specific foundary specific to these numbers? No other distinguishing codes on this stove for more specific maker.

coaly · Aug 4, 2013

Not sure about markings on '76 doors. Mine have no markings inside from Michigan and PA. Not sure how many foundries were being used in 76. I would think they all came from Oregon, or close to home at that time. Mine are also the first style trees;

EddieOne · Aug 5, 2013

Any specific grease recommended for lubing up the draft cap bolts? I was just going to simply use automotive grease unless there was a better recommended type.

coaly · Aug 5, 2013

Any high temp grease. The stuff that shows on the inside door pics above is silver anti sieze. That's even higher temp than wheel bearing or most moly grease. The brush in can reaches through the intake opening on the back and coats the threads hot or cold. Keep it on the hinge pins too. Many times they don't budge. Rotating with PB Blaster gets them moving. After you drive rusted dry ones out, you can wire wheel the pin and clean the hole. You should be able to remove the pins with your hand once they are free and greased a while.

SimonS · Aug 20, 2013

Coaly -> Question about my "new" GrampaBear stove. Bought this stove knowing I was going to have to do a bit of work to it. Biggest issue is the right door seems to sag a bit. The stove has welded rod around the stove entry door, swinging doors have receiving groove. It sags to where they make contact and does not seal well. Can take picture if needed. It's not terribly off, but definitely not closing properly.

I was reading your other posts and you mentioned replacing the hinge pins can help with alignment issues. Do you think this is the remedy I need for my problem? It also seems like there is a little opening between the doors at the top where I can look right into the stove. Concerned this will be an issue trying to dampen the stove down. Hoping its the door alignment issue...

Thanks for any help. Really appreciate it.
Went from a Grandma Bear to a Heritage Soap Stone and now back to a Fisher.

SimonS · Aug 20, 2013

Picture of doors fitting improperly... Worn hinge pin issue?

Picture of said gap. Can look right into the firebox. Confused?

coaly · Aug 20, 2013

Open one door, then lift up on the door that's shut to see if there is movement at the hinges. It will probably rock back and forth showing how much play is in the hinge hole and pin. Removing the hinge pins will show if they are still round, or worn egg shaped that makes the pin smaller and allows the door to drop. (if it's the type with pin that removes from the top ; some early doors do not have door ears drilled completly through with a visible rivet head on top, they are the "lift off" doors) If you have 3/8 bolts without threads under the head that gives you a 3/8 shaft about 1 1/2 inches long, try that in place of the hinge pin that should be 3/8" diameter. That will show you how the door would fit with new hinge pins. The pin usually wears more than the hole, so replacing the pin takes up most of the slop.

If the hinge pins are tight and you need to raise door, (wear of bearing surface) lifting the door and trying a thin washer under each door hinge ear (top and bottom) may raise the door for a better fit. Many times one hinge plate will be welded a touch higher that takes more door weight than the other hinge plate. (both door hinge ears should rest on the hinge plates to share door weight) A feeler gauge can be used to measure clearance if all the weight is on one hinge or the other. Different thickness washers can shim the space between door ear and hinge plate to obtain contact on each hinge bearing surface. A brass washer or shim stock is the perfect material softer than the cast door hinge and steel hinge plate. The main thing is to keep them well greased or lubed with anti-seize to prevent wear once you get them adjusted just right. If it squeaks, it needs grease !

KristenGood · Sep 18, 2013

Hi Coaly, I posted this somewhere else on the forum, but I was wondering if you or anyone can answer. I am looking for the dimensions of the baffle for our Grandpa Bear - its three hours from here and I can't measure it! I noticed some people do two sheets and weld together? Can I just do one sheet? Sorry, I am a rookie! I want to get it ordered so we can take it up and get it installed (getting chilly in the mountains!) Thanks in advance for all of your help! Kristen

Dave K · Sep 26, 2013

Hi guys! I just purchased a home and it has a fisher stove in the basement! I think its the Grandma Bear or the Grandma Bear III. How can I tell?

coaly · Sep 28, 2013

Here's a picture of Dave's stove in question;

I'll copy my answer here in case others have the same question;

Hi,
The picture doesn't show the corners, but the legs look like the angle iron type that go up the sides. (Any stove with bent corners is a III except for the transition period in 1979) The series III with the redesigned one piece box for 1980 no longer had angle iron down the corners. However, there are some series III with the old style box with welded corners and cathedral doors like yours with GM / GP III tags. So if it has angle iron welded corners, and no tag, I'd guess it to be a II around 1979 when they first offered the arched top doors along with the flat top. Could be a III before they had tags too. (If there was ever a III without tags, not sure about that)
I have a tag marked Jan 28, 1980 with a III, so they started tagging them early in 1980.

That's the only one I've seen with the old style welded corner box and a III on the tag. Otherwise I'd say all the III series were one piece box with bent corners.
This one is a transition stove from II to III, one of the first tagged for 1980.
They also started putting baffle plates in the III. It surely needs one if never equipped!
I don't see a damper in the pipe either. That's a must too. They burn wild without being able to close it off when kindling a fire with small pieces.
The Fisher's sent revised prints to the fabricators, and it was up to the individual license holders as to which models they would make and sell. So some were slow to change things to the newer prints. Some made only a few models, but all were sent the prints. This is why production of different models varies. What state, assuming it's in the US ?
Paul

NH Hunter · Oct 7, 2013

What a wealth of knowledge this site is - I'm glad I found it. Quick question for those of you in the know. I've been running a Fisher Mama Bear since I was about 10, first at my parents then I put one in my house. I recently found a Grandma Bear and bought it. I'm giving my oldest son my Mama Bear. Well I'm trying to get the Grandma set up and 8" pipe is not fitting, in or out. I called a local shop and asked and they said that older Fisher's were sometimes metric pipe. I've left a message for a local sheet metal hvac outfit to see if they will make a custom pipe for me, and also found an outfit in Maine that says they carry metric and will make custom pipe.

Long way of asking if any of you have run into a top side flue which is not compatible with standard 8" pipe and if so, what did you do to get up and running.

Thanks in advance.

Mike

coaly · Oct 7, 2013

Welcome to the Forum; They are not metric.
The flue pipe material on Grandma and Grandpa is 3 1/2" long X 8 inch O.D. pipe with .125 (1/4") wall. (that makes the inside of the pipe 7 1/2") The tolerance given to fabricators when buying material was 7.990" + - .020 meaning no smaller than 7.970 and no larger than 8.010 O.D. The hole cut in the steel sheet for the flue was to be 8.040. You can educate your local stove shop with that trivia.......

That's from the original drawings in a perfect world, but the guy with the torch had the final say.
Pipe manufacturers vary, but that's the size specified.

There are many posts on the forum about connecting connector pipe to the smaller I.D. on older stoves. (newer stoves have flue outlet pipe made for stove pipe to fit into that is 6 and 8 inch I.D. not O.D.)
https://www.hearth.com/talk/threads/connecting-a-grampa-bear-wood-stove.73953/#post-934774
The easiest way is to over-crimp your pipe going into the stove. The deeper you put the pipe end into the crimpers, the smaller it will make the pipe. It should be installed crimped end (male) down. If you ever cut pipe, you'll need the tool to crimp the male end smaller to fit into the next piece. With hand crimpers, simply squeeze the pliers until the end crimps down small enough to fit into the stove's flue pipe. A "full" crimp, or taking a bigger bite on the pipe is about twice as much as a factory crimp that is just enough to slip the pipes together.

NH Hunter · Oct 7, 2013

Thanks I'll see what I can do tomorrow. I appreciate your assistance.

Mike.

tarscraper · Oct 31, 2013

coaly said:
Later stoves had 1 1/2" angle iron welded on an angle for a shelf to set the plate on. I've found it easy to set the plate on top of the rear brick retainer and prop it up with a brick (on top of the side brick retainers) on each side. Angle the front edge of baffle upwards, towards the bend in the top plate. Sliding the 2 bricks at the sides fore and aft adjusts the plate on a steeper angle. As long as you're careful loading and don't knock the bricks out, it seems to stay in place fine. If you want to make it more solid, weld or bolt angle iron pieces onto the plate to act as vertical side plates to keep the upright bricks standing on edge firmly.

View attachment 107653 Factory smoke shelf baffle in top vent with baffle on angle iron brackets.

View attachment 107656 Angle iron I added to homemade baffle to keep side prop bricks standing against stove sides. They could be bolted to plate if you don't have welder.

View attachment 107658 Keep the angle iron towards the front of plate, it will only set on the corners of bricks. Yours won't have the welded on "shelf" in the back that this one sits on;
If you want the back of plate higher than sitting on the brick retainers, (as shown in first pic above, to allow higher wood load under baffle) you can add a piece of angle iron across the back like the sides. Place a brick on edge, or cut one lengthwise in half, centered across the back to set it on. The angle iron will keep the rear brick tight against the stove back just like the sides. Firebricks snap clean and easy with a scored line using a masonry blade in a circular saw. They are quite soft compared to red brick or stone.

Hint; I've learned to wedge a piece of wood between the upright standing bricks to hold them tight. Then angle the baffle plate through the door and set the baffle plate (flat - horizontal) on top of them. By sliding the plate to the rear, it drops down on the rear shelf and is in place. Have done a few with a stove full of embers wearing welding gloves.

Hi Coaly and all,

I have been reading all I can about the Grandpa Bear stove. I just bought one and I am going to pick it up in a week or so. Its in good shape overall. Has some surface rust on it. Doors align nicely and bricks are good. It does not have a baffle. Anything more I need to know other than whats on this post to make one? Also sanding and painting the stove. Any recommendations? I am all ears. I have never done this before. This stove will live in my barn/shop. My other 2 stoves int eh house were brand new Jotuls. Thanks!

NZ_Sam · Feb 7, 2014

Can anyone tell me what type of fisher I have? It has two doors, 6" flue, opening is aroximately 43cm so that's about 17" or 18".
Tag on the back says it was manufactured in Wellington new Zealand.
I suspect it is a grandma bear, but only has 6" flue.
Our house was built 1970, and I suspect the stove was installed at that time.

coaly · Feb 7, 2014

Hi Sam and welcome to the forum.
Only single door stoves existed from 1973 to 1976. The idea for viewing the fire with a wider double door stove started in 1976. The production in New Zealand started later than that by a couple years. Probably a Grandma, and doors may have a G/M L inside for Grandma Left and G/M R for right. Most there had tags and Grandmas were popular. Door opening would be 44.45 cm wide. (17 1/2 inches) The 6 inch doesn't make sense for a Grandma, but there are some examples of special built stoves with 8 inch vents on single door stoves that normally would have 6. That is also the door width of some other models that would have a 6 inch outlet.
A picture would help tremendously. If you have a problem posting, you can email them to [email protected] and I can post them for you.

Here's a picture of Grandma doors. You can tell if you have Grandma doors by the close space between trees at the center door seam.

Since mixing coal with wood is a common practice there, the 6 inch outlet would be beneficial for coal use. Notice your tags state "for solid fuel" and not "wood use only". The larger 8 inch was used on double door stoves for open door burning to avoid smoke roll in with doors open and screen in place. They do work fine reduced to a 6 inch all the way up, and Grandma's firebox is smaller than the single door Papa that has 6 inch. So it's only a open door burning issue that seems to work fine even with doors open when reduced to 6.

Here's a NZ tag from a "Wood Lord" boiler. They didn't have a model designation on the tags.

Fisher Stoves Traditional is the company still making the stove models there now, and back then it was Fisher Stoves Classic. The new company has no records or manuals from the previous, when yours was made.

tommyg · Mar 21, 2014

tarscraper said:
Hi Coaly and all,

I have been reading all I can about the Grandpa Bear stove. I just bought one and I am going to pick it up in a week or so. Its in good shape overall. Has some surface rust on it. Doors align nicely and bricks are good. It does not have a baffle. Anything more I need to know other than whats on this post to make one? Also sanding and painting the stove. Any recommendations? I am all ears. I have never done this before. This stove will live in my barn/shop. My other 2 stoves int eh house were brand new Jotuls. Thanks!

View attachment 116324

Tarcsraper,
My stove does not have the baffle either but still will really put out the heat.

You can try to use an inexpensive sandblaster from harbor freight. That will clean it up nicely. As far as pain any high temp paint will work from the pain on to the spray cans. That way you can change any color you want.
by the way nice looking stove. Hope it works well for you.

tamman · Apr 27, 2014

Hi Coaly and all.
Just found a pretty nice Grandma bear, that I have decided to help out of hibernation.
After reading and learning a lot from all your information here, some critical info. that
I don't find is in regards to its two vents. One on top and one on the side, making it
look like you could install the chimney top or out the backside. But there is a box
baffle mostly closing off the rear vent.
I read that for heat retention the rear vent is the best way to go. Do I have this option
or is this set up for only top chimney and rear vent barometric dampener. If so how
would one get a baffle in? Any help would be appreciated, thanks so much.

Tamman

coaly · Apr 27, 2014

Welcome to the forum;
You're describing a barometric stove.
Here's a thread picturing the box that is actually the intake on the rear, and they vent out the top. Try the search feature at the top of the page and search the word "barometric" by my posts in this forum for many more results and description of the barometric damper operation. It is advised to cap the rear intake into chimney, and install a manual damper in the first section of vertical pipe going out the top. Once you understand the operation of a barometric damper, you will realize In the event of a chimney fire, the damper would OPEN the flap which is CLOSING the damper to reduce draft during normal operation. This allows oxygen into the chimney to fuel the chimney fire. They are commonly used on most coal stoves to control the draft with more precision than you can manually. There is no creosote danger with coal, so the chimney fire is not a concern with that fuel.
https://www.hearth.com/talk/threads/project-grandma-bear.82459/#post-1057088

tamman · Apr 28, 2014

coaly said:
Welcome to the forum;
You're describing a barometric stove.
Here's a thread picturing the box that is actually the intake on the rear, and they vent out the top. Try the search feature at the top of the page and search the word "barometric" by my posts in this forum for many more results and description of the barometric damper operation. It is advised to cap the rear intake into chimney, and install a manual damper in the first section of vertical pipe going out the top. Once you understand the operation of a barometric damper, you will realize In the event of a chimney fire, the damper would OPEN the flap which is CLOSING the damper to reduce draft during normal operation. This allows oxygen into the chimney to fuel the chimney fire. They are commonly used on most coal stoves to control the draft with more precision than you can manually. There is no creosote danger with coal, so the chimney fire is not a concern with that fuel.
https://www.hearth.com/talk/threads/project-grandma-bear.82459/#post-1057088

Thanks for that. Assuming I cap the rear intake, how would I then baffle the stove? Does the box from the rear vent have to be removed?
I take it that there is no way to convert this to rear chimney and cap off the top vent? Is the advice still to reduce the 8 inch flue down to
6 inch with a manual dampener just above the collar?

coaly · Apr 28, 2014

I have not put a baffle in a stove with the inner air box. Not sure if it's in the way or not.
To make it a rear vent, you would need to remove the air box and cap the top vent with minimum 1/4 inch steel plate or 5/16 thick plate to match the rest of the stove top. Reducing to 6 works fine, not technically legal to reduce by code, but many are in operation reduced with no draft issues.

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