Early Model Fisher Papa Bear Baffle Question

[Crmaverick]

I have an early model papa bear that came with my house (single story ranch). I had a new chimney built last year and have an 8” flue running directly to it with no liner and it pulls a nice draft.


I’m looking at doing one of those baffles but it appears I don’t have the rear metal table below the exhaust exit as pictured in the sticky thread that the rear baffle sits on. Has anyone done one of these without that tab or have an idea of what would work? Stack bricks all the way to the rear wall?

Thanks

 

[Jeremy B.]

I have the same old model like that . with the chrome ball handle and the pipe caps for draft knobs. I have also tried to look at adding a baffle plate to mine. If anyone does have that answer it could be helping atleast a couple of us. I love the heat from the fisher and would love to hold even more of it.
Jeremy

 

[Crmaverick]

I found this thread:

Modifying the baffle in my Old Fisher Stove (wood burning stoves forum at permies)

This is essentially what i used to have for a baffle . My next project is making a rocket oven!.

permies.com

Maybe we just need to add a full second top course of brick and put the plate on that?

 

[coaly]

Set the baffle on the rear brick retainers. Bricks on their sides along sides support the front of plate to desired height buy sliding bricks fore and aft to raise and lower front of plate to correct height.

The original poster with 8 inch chimney needs to set baffle plate for the same square inch opening as the chimney. If this is a nominal 8 inch masonry flue, they normally measure 7 1/2 square which would require minimum 56.25 square inch venting space where exhaust travels through. An insulated chimney is preferred for the minimum smoke space. Uninsulated will require more heat left up, requiring larger smoke space. Adjust baffle for the chimney, not the stove.

Make a cardboard template. Set on brick retainers at rear, pointing front of baffle towards lower bend in top, or just ahead of it. Adjust height for proper opening for chimney square inch opening. If pipe configuration, or chimney height does not produce sufficient draft, lower plate until no smoke roll in is observed when opening door slowly.

 

[Crmaverick]

Set the baffle on the rear brick retainers. Bricks on their sides along sides support the front of plate to desired height buy sliding bricks fore and aft to raise and lower front of plate to correct height.

The original poster with 8 inch chimney needs to set baffle plate for the same square inch opening as the chimney. If this is a nominal 8 inch masonry flue, they normally measure 7 1/2 square which would require minimum 56.25 square inch venting space where exhaust travels through. An insulated chimney is preferred for the minimum smoke space. Uninsulated will require more heat left up, requiring larger smoke space. Adjust baffle for the chimney, not the stove.

Make a cardboard template. Set on brick retainers at rear, pointing front of baffle towards lower bend in top, or just ahead of it. Adjust height for proper opening for chimney square inch opening. If pipe configuration, or chimney height does not produce sufficient draft, lower plate until no smoke roll in is observed when opening door slowly.

Thanks should this plate be sitting flat or tilted at an angle?

Also how far forward should the plate come? I’m wondering if it stays in the stepped up portion of the rear firebox or comes from the back into the forward shallower section closer to the door.

I’m running directly into a new 8” chimney flu.

 

[coaly]

Closer to the door under the lower top section. Angled upward at front to adjust opening for correct square inch opening.
Set cardboard template on rear brick retainers. cut it large enough to go past lower bend in top. Angle up ward for correct opening and set side brick supports. Make cardboard templates until you have it just the right size. Make the same thing using 5/16 steel plate. Set in place. If you want to insure bricks do not fall in, bolt or weld angle iron to baffle to hold bricks in place against side walls. Photos and much more information in baffle thread in sticky section at top of the Fisher Forum home page;
https://www.hearth.com/talk/threads...d-fisher-more-heat-less-smoke-under-25.74710/

If the 8 inch chimney is round, 50.24 minimum square inch opening for exhaust travel.

 

[Crmaverick]

Closer to the door under the lower top section. Angled upward at front to adjust opening for correct square inch opening.
Set cardboard template on rear brick retainers. cut it large enough to go past lower bend in top. Angle up ward for correct opening and set side brick supports. Make cardboard templates until you have it just the right size. Make the same thing using 5/16 steel plate. Set in place. If you want to insure bricks do not fall in, bolt or weld angle iron to baffle to hold bricks in place against side walls. Photos and much more information in baffle thread in sticky section at top of the Fisher Forum home page;
https://www.hearth.com/talk/threads...d-fisher-more-heat-less-smoke-under-25.74710/

If the 8 inch chimney is round, 50.24 minimum square inch opening for exhaust travel.

Thanks for the info. I have a square flu so I’ll shoot for that 56.25 number. About how far back from the door should that plate stop? Or should it end right about where the fire box steps up in height.

 

[coaly]

Thanks for the info. I have a square flu so I’ll shoot for that 56.25 number. About how far back from the door should that plate stop? Or should it end right about where the fire box steps up in height.

That changes with available draft. I would go just to, or a little past the lower bend toward the front. If you had a 6 inch insulated chimney, you could keep more heat in the stove. The plate could come closer to the door, and square inches would be the same as stove outlet. Your chimney requires lots of heat, so you can’t baffle it to the max.
The larger the plate toward the front, the more resistance you are adding to the firebox. Many factors are needed, so trial and error will show if you need to drop the plate at front to allow more heat up. You can only make the stove as efficient as the chimney, and you don’t have a efficient chimney to work with. You are going to be cleaning creosote a few times a burning season without letting tons of heat up. Check frequently until you know how much creosote you are forming.

Was this chimney built for this stove? (since it’s the wrong size) Is it built to current code? This would require an insulated liner, if not built with proper clearance.

 

[Jeremy B.]

Thanks Coaly,
I have read a ton of your posting on here. i have looked through most of the available information about adding a baffle. my fisher does not have the brick holder clip below the 6" outlet pipe on the back of my stove. it does have a pair of clips about a third of the way up from the back. Is that where you are talking about resting the plate? since we are well into the heating season here in Vermont and i don't let my fire go out, would it be equally effective for the rest of the season to buy an 18" length of stove pipe and put that inside the stove into the outlet pipe? or will that cause problems. I have a ton of draft, pipe comes out the back elbows up immediately and goes straight up through the roof. i have about 5 feet of exposed stovepipe going up out of the stove and then to metalbestos for the remainder of my run, maybe another 14' and comes out the peak of my roof. its an oldie with the crome ball handle and no bend on the handle arm. Thank you for all the help.

Jeremy

 

[coaly]

Yes, the brick retaining clips are at the same level all around the stove. The small flat plate under outlet was a very small baffle plate.

Never tried a piece of pipe inside. Try it, if you have an IR thermometer document some upper and lower stove top temps, rear, and pipe temps to compare after putting the pipe on.

You have a diagonal type firebox now. The air comes in lower bottom front exiting upper rear. Anything to keep the gases from combustion inside longer instead of the direct path is going to make a difference. Think of the pipe you’re adding is like a vacuum cleaner pulling the smoke and heat out. That’s exactly what the chimney does. Don’t know how long that piece of thinner pipe will last, but it has to be better than straight out the back. We’re calling this the Jeremy Baffle, no matter how it works.

 

[Jeremy B.]

Yes, the brick retaining clips are at the same level all around the stove. The small flat plate under outlet was a very small baffle plate.

Never tried a piece of pipe inside. Try it, if you have an IR thermometer document some upper and lower stove top temps, rear, and pipe temps to compare after putting the pipe on.

You have a diagonal type firebox now. The air comes in lower bottom front exiting upper rear. Anything to keep the gases from combustion inside longer instead of the direct path is going to make a difference. Think of the pipe you’re adding is like a vacuum cleaner pulling the smoke and heat out. That’s exactly what the chimney does. Don’t know how long that piece of thinner pipe will last, but it has to be better than straight out the back. We’re calling this the Jeremy Baffle, no matter how it works.

i love it...i will give it a shot soon.