# Added a baffle to Grandma Bear Fisher Stove (updated with 2ndary burn idea)



## pen

Look in my avatar to see my 1981 Grandma Bear fisher wood stove.  Been in service every year since install and is a general workhorse (I mean, what is there to fail).

In an attempt to save the environment and perhaps get some more heat out of less wood, I designed a baffle that a friend in a metal shop made up for me.  Last night I was able to cut firebrick to fit, and install.

Here is what it looks like now.  Before there was nothing stopping the flames from going directly up the chimney!

The entire thing is made out of 3/16 thick angle iron (doubled down the center).  Hopefully it will withstand the heat over time.  







The opening now that allows the gasses to enter into the top chamber of the stove is just slightly larger in area than the area of the 8in flue pipe exit.

It is pretty early in testing, but the first day seems to be good.  

So far I am noticing that my stove surface temps are staying as high as normal for longer and on less wood.

I am also seeing my chimney pipe temperatures running lower than normal.

It will be an adjustment period as I learn whether or not it is better to leave the damper on the stove pipe wide open now, or close it some and increase my primary air intakes to maintain a sufficient flue temperature.  Guess I'll be making the neighbors wonder what I am up to again by making 50+ trips out on the deck to see if smoke is coming out of the chimney.  

I am going to clean the chimney today once the stove burns out later this morning so I can start on a clean chimney and see if this will change (for the better or worse) my chimney cleanliness.

This definitely is not as efficient as a secondary system, but hopefully will prove to keep the smoke down in the heat a bit longer and perhaps result in a bit more heat and cleaner burns.

My only concern is that perhaps the extra heat that is kept down on the wood because of this baffle may cause the wood to pyrolize and there may not be enough air present to sufficiently burn it.  If this is the case, I am hoping that by reducing the stack damper I can increase primary air to aid with this.  However, utilizing the stack damper also slows the speed of the effluent, giving it a better chance to reduce as creosote.  If this is a problem, I could even remove a firebrick from the front of this, back, both, who knows.

Sooo, it may be of help, or not.  But the way it is designed it can be easily removed.

Let the experimentation continue!


pen


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## Pagey

Nice!  I certainly hope this works well for you, and I look forward to hearing your results.


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## peakbagger

Too bad that you didnt have primary air ports on the back side of the stove instead of the front door. Then install some secondary ports on the upper chamber and you would probably pick up more efficiency.


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## Yamaha_gurl

So, a baffle is only a plate that prevents all the flames from going up the chimney? Sorry, newbie alert :red: If so, I'm lucky...my fisher already has one :D


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## pen

Yamaha_gurl said:
			
		

> So, a baffle is only a plate that prevents all the flames from going up the chimney? Sorry, newbie alert :red: If so, I'm lucky...my fisher already has one :D



Funny you mention that.  My buddy who has a grandma bear "like" stove built by kodiak had a smoke shelf as well.  This one simply did not.  

Any chance you could take a picture of yours?  I am curious to see what it looks like.

pen


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## Todd

peakbagger said:
			
		

> Too bad that you didnt have primary air ports on the back side of the stove instead of the front door. Then install some secondary ports on the upper chamber and you would probably pick up more efficiency.



Or put a bypass plate on the rear of the baffle and a cat in the front.


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## WES999

The baffle looks good, I would expect you will see higher stove top temps now. Looks like you could add secondary burn tubes like I did on my stove without too much trouble.


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## BJ64

Neat and simple.  I like it a lot!

If nothing else you added more thermal mass to the stove.  I'm just a dim-wit on these things but that should do some good.

I'm excited to see how this works as well!


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## meathead

Thing of beauty


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## pen

Thanks for the kind words.

The chimney didn't get cleaned today because the snow started a bit earlier than I anticipated.  I'll wait until tomorrow when things are a little calmer to climb up on the roof.

Just went from 11:15 to 3:15 on 3 medium pieces of wood.  Wasn't much of a coal bed to start with either.  Stove temps stayed right up in the normal range for my stove until the last 1/2 hour.  That is a much longer and hotter burn than I have ever gotten without that.  A typical small load for that stove is 5 pieces of wood.  3 usually won't burn for beans as it didn't maintain enough heat near the wood for a decent burn.  It took 5-6 to create enough of its own critical mass to make a good clean fire.

Initial results are good. 

pen


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## Redox

I like it!  I always thought there should have been something up there to stop the flames from going right up the stack.

I hear some secondary air tubes calling your name!  Know any adventurous welders?

Chris


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## fossil

3 or 4 perforated tubes running E-W, or a simple perforated baffle plate mounted beneath that new shelf, provided with a source of secondary combustion air, perhaps.  Don't stop experimenting.  Rick


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## begreen

Great job on improving the old gal. I agree with Rick. If nothing else put in a perforated pipe going across the front of the baffle with it's own air supply. Put some sort of valve on it to regulate the secondary air and I think you'll be pleased by the result.


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## pen

Thanks for the words of encouragement.

I would love to have secondary air that is adjustable since I do use the spark arrestor screen from time to time so that the fire can burn and I can watch it with the door removed.   (which seems to radiate much more heat, slows down the burn, and surprisingly does not put smoke into the room at all since the addition of the baffle).  

I think I am going to have to wait and see for a while how successful these results are.  This device is removable as soon as the stove slows down.  Even though this is an old stove and worthless to many individuals, it really did burn very well with good wood on its own.  The only problem is that it consumed about 30-40% more wood!

I am a bit nervous about modifying the stove itself!  I know I could always block off the hole that I would create for secondary burn tubes if it didn't work as I designed them, but that's a leap that is going to take a little bit of working up to on my part   In time I suppose.  Just hard putting a drill to a stove that I love even if I intellectually know the results.

pen


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## fossil

Think about the penetrations that already exist and whether or not you could use one of them to your advantage.  For example, there's no reason secondary combustion air couldn't be fed down through the flue collar somehow...it'll go that way if the stove has a good draft, and that would tend to preheat the secondary air, which is a good thing.  That way, you'd be modifying the stovepipe rather than the stove.  The secondary air supply duct itself probably doesn't need to be any bigger than maybe 3/4" i.d., if that.  Just a thought.  Rick


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## pen

That is a good idea about running it down through the stove pipe.  Worst case scenario I would be out a 2 foot length of pipe.

How's this for a simple idea.  

Drill a hole in the stove pipe below the damper.  

With a 90, Attach black iron pipe below damper (3/4in) and secure.

Create a way to make the amount of secondary air adjustable here.  

Run the black pipe down through the stove pipe, into the stove and through the center firebrick in my baffle by drilling a hole.  

Tee off to the left and right.  Drill 3/16in holes every 1 1/2 inches along pipe

Do you think black iron pipe would hold up?  I don't have easy access to stainless.  Any thoughts as always are welcome.

pen


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## Hogwildz

That might be a tough sell.
The secondary pipe in the exhaust stack is going to be fighting the draft upwards, and may end up sucking air & gases into the secondary tube, rather than blowing super heated air out out create secondary burn.


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## Adios Pantalones

I'd be tempted to run the air from the bottom.  Hot air rises.  You'll be fighting gravity if the intake or some run of the pipe goes too far above the secondary tube.  The secondary tub might then become a secondary exhaust tube.


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## Peter B.

pen:

I respectfully disagree with the last two posters.

A number of years ago, I installed a rudimentary secondary air system in a Jotul 118 - through the stovepipe and down into the stove.  It drew fine.

Some folks seem to think that smoke 'pushes' it's way up the chimney, and will use any available seam to leak out.  The truth is otherwise.  Basically, if you have adequate draft, you can visualize your chimney as a huge vacuum cleaner... and you can introduce air at any virtually any point on the stove (or pipe) and air will be drawn into the system.

Only when the draft is *NOT* adequate will there be a problem with smoke exiting from the 'wrong' hole.

--

Black pipe is likely to last a few seasons, but may oxidize internally and clog the secondary drillings/passages.  I've used copper for my 'experiments' in past, which has the same problem, but is a little easier to work with... and can be swapped out for stainless once you've arrived at a final design.

Looks like a fun project, by the way.

Peter B.

-----


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## Hogwildz

Yes and with that vacuum cleaner like suction of draft going up, how is the secondary tube going to be pushing hot air for secondary combustion out those jet holes? It won't, it will also be sucking air into the holes rather than blasting out. The only secondary that may or may not happen is going to be in the stack, not in the firebox where you want it to burn the gases from the wood & make the heat inside the stove.


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## jacksnipe

I'm thinking about installing one of these items in 1/2" NPT & drilling a hole into the firebox to accept it. if it doesn't work out a recessed plug could be installed to block it off.
 I hope the picture comes through so you get an idea what I'm thinking about.


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## pen

Hogwildz said:
			
		

> Yes and with that vacuum cleaner like suction of draft going up, how is the secondary tube going to be pushing hot air for secondary combustion out those jet holes? It won't, it will also be sucking air into the holes rather than blasting out. The only secondary that may or may not happen is going to be in the stack, not in the firebox where you want it to burn the gases from the wood & make the heat inside the stove.



The pipe would not be open at all in the stove pipe.  Rather my hole for getting fresh air would simply be in the stove pipe and the sealed pipe would then run down into firebox through the baffle.

My thought was that cooler air moves towards warmer air.  As such, with the opening being outside, and the pipe warming its whole way into the burn chamber that it would have the natural draw regardless of being up or down.  But that was my reasoning and it has proven to be less than sound at points!

Keep hashing out ideas, the more the better.

Thanks guys

pen


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## Peter B.

Hogwildz said:
			
		

> Yes and with that vacuum cleaner like suction of draft going up, how is the secondary tube going to be pushing hot air for secondary combustion out those jet holes? It won't, it will also be sucking air into the holes rather than blasting out. The only secondary that may or may not happen is going to be in the stack, not in the firebox where you want it to burn the gases from the wood & make the heat inside the stove.



Again - respectfully - you're wrong.

I run a simple secondary tube in my current stove through a drilling near the flue outlet, and *down* into the stove.

I would see smoke from the tube orifice if the tube was 'sucking backwards'.  I don't... and the burning match/cigarette/incense stick proves air is going *in*.

Peter B.

-----


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## Peter B.

jacksnipe said:
			
		

> I'm thinking about installing one of these items in 1/2" NPT & drilling a hole into the firebox to accept it. if it doesn't work out a recessed plug could be installed to block it off.



Unless 'strategically located', the fitting alone won't do much (if any) good... and if the air isn't preheated at all you're just introducing an extraneous hole in the stove.

You'd want to attach a tube to the fitting (at least), extending into the stove (and the smoke path)... and figure out some means of heating the air before it leaves the tube.

Peter B.

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## Todd

I wouldn't fart around with secondary air tubes if that was my stove. Instead I would make a slide in cat in front of the baffle similar to what Peter did with his pot belly.
https://www.hearth.com/econtent/index.php/forums/viewthread/28554/#300761


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## Peter B.

I seem to have made a bad habit of 'borrowing' other people's threads, for which I apologise...

--

Todd:

I first modified my stove when catalysts were 'the rage'.  I'm now inclined to think an effective secondary air system is both more 'elegant' and better suited to the average (read: casual) wood burner.

Introducing another control (bypass or catalyst slide) to normal operation is clunky if you can achieve nearly the same effect without.

But I don't plan to give up my own catalyst any time soon.

Peter B.

-----


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## pen

Peter B. said:
			
		

> I seem to have made a bad habit of 'borrowing' other people's threads, for which I apologise...
> 
> --
> 
> Todd:
> 
> I first modified my stove when catalysts were 'the rage'.  I'm now inclined to think an effective secondary air system is both more 'elegant' and better suited to the average (read: casual) wood burner.
> 
> Introducing another control (bypass or catalyst slide) to normal operation is clunky if you can achieve nearly the same effect without.
> 
> But I don't plan to give up my own catalyst any time soon.
> 
> Peter B.
> 
> -----




All ideas are welcome.  I do appreciate the suggestions and see no reason to stop here!

pen


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## bokehman

Pen, going out the flue exit is fine if you don't want to drill the stove. If the pressure outside the stove is greater than inside the stove (which of course it is once there is a fire burning) air will enter the stove through those pipes. If you wanted to be fanatical you could terminate the secondary air entry at a lower point than the fire (just to satisfy the doubters). You don't need to regulate the secondary air. It's not regulated on EPA stoves except by the hole size. For the pipe I would go with mild steel, not iron. It's easier to work with; you can weld it with mig, tig, or arc; and it bends really easily. On my insert there are 2 rows of tubes, one at the back of the baffle (like your diagram) with ten 1/16" holes, and another along the leading edge of the baffle with ten 1/16" and ten 3/16" holes.


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## glfporsche

Hi, I'm new to this forum. 

Secondary air tubes are totally doable. Here's the installation I did on my old Lopi. 

http://www.glfporsche.smugmug.com/gallery/6450885_NdHjA

You'll notice the air inlet is the highest point in the system. Smoke will come out of the inlets, but ONLY when the doors are OPEN. To comment on the previous debate; once the stove is closed up the air pressure inside the stove is LOWER than the surrounding air. ANY opening will allow the higher pressure surrounding air to push its way in, no matter where the opening is located. Notice I did not say it "draws air in". You can not pull on air any more than you can push on a rope. In my case the inlet air tubes let air in once the doors are shut, but will let smoke out when the doors are open. 

As a side note: the inlet tubes shown in the pictures (top tube that bends 90 degrees into the box beam) are very undersized. I have since cut very large holes into each side of the stove leading into the box beam, and welded a vertical 1x2 on each side to feed the holes with air. The air now comes in at the bottom of the stove, so there is no smoking problem when the doors are opened. The resultant secondary combustion is impressive. I'll have to post some flame picts. You can see by the chimney shots, it burns quite clean.

BTW, does anyone know what kind of Lopi this is? I got it used. It was built in 1983, but that's all I know.

Kris

Modified Lopi
Quadrafire 3100i


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## jacksnipe

Peter B. said:
			
		

> jacksnipe said:
> 
> 
> 
> 
> I'm thinking about installing one of these items in 1/2" NPT & drilling a hole into the firebox to accept it. if it doesn't work out a recessed plug could be installed to block it off.
> 
> 
> 
> 
> Unless 'strategically located', the fitting alone won't do much (if any) good... and if the air isn't preheated at all you're just introducing an extraneous hole in the stove.
> 
> You'd want to attach a tube to the fitting (at least), extending into the stove (and the smoke path)... and figure out some means of heating the air before it leaves the tube.
> 
> Peter B.
> 
> -----
Click to expand...

 Actually 2 of these fittings would need to be installed, one on each side of the firebox. The fittings would be connected to  manifolds that sit on top of the firebrick retainers.  Running between these 2 manifolds would be 3 - 4  1" diameter perforated tubes. The manifolds would be closed on the both ends, I was thinking about a manifolds that  are  1 1/2" x  3"  x  18" long..
 I didn't  know that the secondary air had to be injected from beneath the fire. If the air doesn't need to be regulated then other options could be considered.


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## bokehman

jacksnipe said:
			
		

> I didn't  know that the secondary air had to be injected from beneath the fire.


Not beneath the fire. It's above the fire, just below the baffle, in the smoke path.


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## glfporsche

Just a bit of advice after having gone through this.  Give the secondary manafold more air than you think you need.  You can always damp it down later.  I would shoot for equaling the primiary air supply.  1/2 inch NPT might not be enough.  

Kris


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## Peter B.

glfporsche wrote:

>Secondary air tubes are totally doable. Here’s the installation I did on my old Lopi.

--

As I once heard it said: "Too good."

Do post some burn pics when you can.  I'll bet pen (and others as well) will be convinced... if they weren't already.

Peter B.

-----


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## jacksnipe

glfporsche said:
			
		

> Hi, I'm new to this forum.
> 
> Secondary air tubes are totally doable. Here's the installation I did on my old Lopi.
> 
> http://www.glfporsche.smugmug.com/gallery/6450885_NdHjA
> 
> You'll notice the air inlet is the highest point in the system. Smoke will come out of the inlets, but ONLY when the doors are OPEN. To comment on the previous debate; once the stove is closed up the air pressure inside the stove is LOWER than the surrounding air. ANY opening will allow the higher pressure surrounding air to push its way in, no matter where the opening is located. Notice I did not say it "draws air in". You can not pull on air any more than you can push on a rope. In my case the inlet air tubes let air in once the doors are shut, but will let smoke out when the doors are open.
> 
> As a side note: the inlet tubes shown in the pictures (top tube that bends 90 degrees into the box beam) are very undersized. I have since cut very large holes into each side of the stove leading into the box beam, and welded a vertical 1x2 on each side to feed the holes with air. The air now comes in at the bottom of the stove, so there is no smoking problem when the doors are opened. The resultant secondary combustion is impressive. I'll have to post some flame picts. You can see by the chimney shots, it burns quite clean.
> 
> BTW, does anyone know what kind of Lopi this is? I got it used. It was built in 1983, but that's all I know.
> 
> Kris
> 
> Modified Lopi
> Quadrafire 3100i


 Very intresting, this is very similar to what I have in mind, although the design that I'm thinking about uses a different approach. You may be right about the 1/2" npt being to small, In looking at your manifold assy, it looks as if it's welded at a slight angle up,  to reduce smoke spillage into the room upon opening the door ?
 I was thinking of using cotter pins etc. on each side of the tubes to prevent them from falling out. One question here is, what is the distance from the flue opening in the stove to the top of the baffle material..


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## fossil

glfporsche said:
			
		

> ...BTW, does anyone know what kind of Lopi this is? I got it used. It was built in 1983, but that's all I know...



Pretty tough to tell from the pics, but it's from the era when Lopi was beginning to understand the direction stoves needed to go.  You've got primary air controls beneath the doors, and a secondary air control over the door.  In that respect, it's similar to my old M520.  The M520 had an 8" collar, and had a firebrick baffle supported by a steel plate high in the rear of the box.  The air through those secondary ports served as both airwash and secondary combustion air supply.  I'll attach a pic of it.  Don't have the stove anymore, but I still have the original owner's manual.  If you'd like to have it, I'll be happy to send it to you.  Rick


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## pen

glfporsche said:
			
		

> Hi, I'm new to this forum.
> 
> Secondary air tubes are totally doable. Here's the installation I did on my old Lopi.
> 
> http://www.glfporsche.smugmug.com/gallery/6450885_NdHjA
> 
> You'll notice the air inlet is the highest point in the system. Smoke will come out of the inlets, but ONLY when the doors are OPEN. To comment on the previous debate; once the stove is closed up the air pressure inside the stove is LOWER than the surrounding air. ANY opening will allow the higher pressure surrounding air to push its way in, no matter where the opening is located. Notice I did not say it "draws air in". You can not pull on air any more than you can push on a rope. In my case the inlet air tubes let air in once the doors are shut, but will let smoke out when the doors are open.
> 
> As a side note: the inlet tubes shown in the pictures (top tube that bends 90 degrees into the box beam) are very undersized. I have since cut very large holes into each side of the stove leading into the box beam, and welded a vertical 1x2 on each side to feed the holes with air. The air now comes in at the bottom of the stove, so there is no smoking problem when the doors are opened. The resultant secondary combustion is impressive. I'll have to post some flame picts. You can see by the chimney shots, it burns quite clean.
> 
> BTW, does anyone know what kind of Lopi this is? I got it used. It was built in 1983, but that's all I know.
> 
> Kris
> 
> Modified Lopi
> Quadrafire 3100i





That is some beautiful work.  You obviously are more than a hobbiest with metal?

The smoking when the doors open is an issue that I was worried about for 2 reasons.  1, I and my wife LOVE the wood stove but do not want to smell like smoke.  We each worth with people that live in homes who do not burn properly or have a draft issue causing back smoking and it is obvious and unpleasant.  Many people who come to our home comment on the lack of a wood burning smell and are surprised that we burn.

This is also of concern because I enjoy burning the stove with the doors open and spark screen in place. 

Thank you for showing me how it SHOULD be done!

pen


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## pen

Thanks to everyone for the responses and ideas.  Here is the impetus for my wanting to install secondary tubes.  

1.  The results of this baffle are unbelievable!  Where an average load of wood used to use 1/4 of the water in my stove stop steamer, I am not going through 1/2 to 3/4 per burn!  An overnight burn will leave just enough to cover the bottom!  To heck with debating stove top temperatures, those results speak volumes of the efficiency gained through this setup.  

2.  While I love the added heat gained from my wood, what I am not happy with is my flue gases.  I now have smoke  I never did before except for about 10 minutes after a reload.  From then on out, it would be nothing but heat waves.  Now, I am getting 30mins on an average load to 60-75 minutes on an overnight load of white smoke from the chimney.  All the while the stove is producing killer heat and the chimney is about 350 degrees (normal).  

While I love the added heat my number one goal is safety.  I cleaned the chimney upon adding this baffle so that I can check to see accumulation as a result of its addition.  

In  the past I get very little build-up in my chimney (a handful after a month of solid burning with this old pre-epa monster).  However, my chimney is exterior masonry and the creosote that I did collect would be the second stage variety from the top third of the chimney.

I have discussed the smoking issue with the metal shop buddy who built this for me, and he believes even with the added smoking that I am going to find less 2nd degree creosote in the chimney since I am no longer needing to use my stove damper and the velocity of my flue gasses will have increased.  

Even if he is correct, the smoking issue bothers me from a smell standpoint (I like my neighbors) and an environmental standpoint (no tree hugger but I don't like making a bigger impact than necessary).

My thought is that a simple secondary, while it may not be perfect, may add enough extra air in the back of this baffle to help better burn this smoke I am finding.  

If I open both doors with a full load it is amazing to see the fire box FULL of flames and the chimney smoke will immediately clear up.  If I add more primary air with the doors closed however I will overfire in no time.  I am hoping that a small amount of secondary air in the right spot will make the perfect balance.

What do ya's think?


pen


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## Hogwildz

Peter B. said:
			
		

> Hogwildz said:
> 
> 
> 
> 
> Yes and with that vacuum cleaner like suction of draft going up, how is the secondary tube going to be pushing hot air for secondary combustion out those jet holes? It won't, it will also be sucking air into the holes rather than blasting out. The only secondary that may or may not happen is going to be in the stack, not in the firebox where you want it to burn the gases from the wood & make the heat inside the stove.
> 
> 
> 
> 
> Again - respectfully - you're wrong.
> 
> I run a simple secondary tube in my current stove through a drilling near the flue outlet, and *down* into the stove.
> 
> I would see smoke from the tube orifice if the tube was 'sucking backwards'.  I don't... and the burning match/cigarette/incense stick proves air is going *in*.
> 
> Peter B.
> 
> -----
Click to expand...


Mayer I am misunderstanding.
Pen just stated he is not drawing the secondary air from the exhaust flue if I read it correctly, but from an outside source separate from the exhaust. That I can understand.
Is this drilling you speak or separate from the exhaust gases? Just curious.


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## jacksnipe

Pen:  You mentioned that with the doors closed & the primary air open it shows signs of over firing quite quickly, what signs are evident of over firing
this bullet proof unit. I have often thought about the ramifications of modifying the Fisher for this reason, I wonder how hot it will run with the baffle installed.  The hotest recorded temps I have ever reached were close to 800 on the stove top, this was indeed quite hot but didin't show signs of over firing. I wonder if adding a baffle will increase this to a dangerous level..
 My thoughts are along the lines of running the unit up to say 500 degrees & closing the draft caps to about 3/4 of turn from full closed.


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## WidowMaker

glfporsche said:
			
		

> Hi, I'm new to this forum.
> 
> Secondary air tubes are totally doable. Here's the installation I did on my old Lopi.
> 
> http://www.glfporsche.smugmug.com/gallery/6450885_NdHjA
> 
> You'll notice the air inlet is the highest point in the system. Smoke will come out of the inlets, but ONLY when the doors are OPEN. To comment on the previous debate; once the stove is closed up the air pressure inside the stove is LOWER than the surrounding air. ANY opening will allow the higher pressure surrounding air to push its way in, no matter where the opening is located. Notice I did not say it "draws air in". You can not pull on air any more than you can push on a rope. In my case the inlet air tubes let air in once the doors are shut, but will let smoke out when the doors are open.
> 
> As a side note: the inlet tubes shown in the pictures (top tube that bends 90 degrees into the box beam) are very undersized. I have since cut very large holes into each side of the stove leading into the box beam, and welded a vertical 1x2 on each side to feed the holes with air. The air now comes in at the bottom of the stove, so there is no smoking problem when the doors are opened. The resultant secondary combustion is impressive. I'll have to post some flame picts. You can see by the chimney shots, it burns quite clean.
> 
> BTW, does anyone know what kind of Lopi this is? I got it used. It was built in 1983, but that's all I know.
> 
> Kris
> 
> Modified Lopi
> Quadrafire 3100i




I like that idea, mind if I borrow it. I might use 3/4 or 1" inlet s though, 1/2 seems a mite small...


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## pen

jacksnipe said:
			
		

> Pen:  You mentioned that with the doors closed & the primary air open it shows signs of over firing quite quickly, what signs are evident of over firing
> this bullet proof unit. I have often thought about the ramifications of modifying the Fisher for this reason, I wonder how hot it will run with the baffle installed.  The hotest recorded temps I have ever reached were close to 800 on the stove top, this was indeed quite hot but didin't show signs of over firing. I wonder if adding a baffle will increase this to a dangerous level..
> My thoughts are along the lines of running the unit up to say 500 degrees & closing the draft caps to about 3/4 of turn from full closed.



I am measuring 600 degrees on the slanted area between the lower and upper levels no problem.  Hitting 800 in the middle of the lower plate now where my steamer sits is very possible.

I have NEVER seen any glowing and intend to keep it that way!  I am not afraid of overheating the stove for fear of hurting it but just don't see a need for taking things to that extreme, and I do not need that much heat!  I think my current burn temps are plenty and are definitely meeting my heating needs.  

I am not looking for more heat exactly from my unit.  More efficiency is really the goal.  So if I can get the same heat out of less wood or a longer burn, then that's a bonus.  If I can get the same heat and have a cleaner burn, bonus. etc.

It is not that I did not reach these temperatures without the baffle, what I am finding is that I am maintaining them for a longer period of time now.

The problem however is my concern regarding the additional smoke I am seeing. 

I think perhaps the smoke clears up in the chimney with the doors open not because I am getting a hotter burn but maybe because the extra air entering the unit is diluting the exhaust gasses?  Not sure.  With the door open the smoke is much less dense and changes from white to a hint of black.

Burning well seasoned beech primarily right now.  Loaded the stove with 2 year old maple just for comparison tonight and found the same thing.  

pen


----------



## karl

Here's an easy secondary add on to that stove.

Cut a hole in the bottom rear of the stove.  Make the hole the same diameter as the outside diameter of some gas pipe.  Use some cutting oil when you drill it out.

Then run a piece of gas pipe through the hole up the back of the stove, put a 90 on it and run it to close to the front of your baffel.  Then put a T on it and run a piece of pipe on each side of it to go across the baffel.  Flatten the side of the these pipes a bit with a belt sander to make then easier to drill.  Then drill a series of holes in the pipes running across the front.

The only big problem I see is putting the hole in the bottom of the back of the stove.  I'm guessing I would use a 1 inch piece of gas pipe, and that hole would be tough to cut.  You might need to use a torch and then you could seal any gaps with stove cement.


----------



## Hogwildz

Since you already have the angle iron framed out for the baffle, why not make a secondary baffle like PE and some other manufacturers make?


----------



## pen

Hogwildz said:
			
		

> Since you already have the angle iron framed out for the baffle, why not make a secondary baffle like PE and some other manufacturers make?



Are you talking about a drilled baffle plate that would rest just below this one?  

pen


----------



## hydrology_joe

glfporsche said:
			
		

> Secondary air tubes are totally doable. Here's the installation I did on my old Lopi.
> 
> http://www.glfporsche.smugmug.com/gallery/6450885_NdHjA
> 
> As a side note: the inlet tubes shown in the pictures (top tube that bends 90 degrees into the box beam) are very undersized. I have since cut very large holes into each side of the stove leading into the box beam, and welded a vertical 1x2 on each side to feed the holes with air. The air now comes in at the bottom of the stove, so there is no smoking problem when the doors are opened. The resultant secondary combustion is impressive. I'll have to post some flame picts. You can see by the chimney shots, it burns quite clean.
> 
> Kris



Impressive handiwork!  I am curious, what is the white material on top of the secondaries?  It almost looks like a foam.  (or impressively white bricks)  

I have an old Fisher insert that I'd like to add secondaries to.  What spacing did you use for your holes?  How did you determine that?  Besides the inlet size, what would you do differently?


----------



## hydrology_joe

pen said:
			
		

> Hogwildz said:
> 
> 
> 
> 
> Since you already have the angle iron framed out for the baffle, why not make a secondary baffle like PE and some other manufacturers make?
> 
> 
> 
> 
> Are you talking about a drilled baffle plate that would rest just below this one?
> 
> pen
Click to expand...


I'm learning vicariously through Pen's efforts here before I attempt my mods.  This may be an easier option than fabricating secondaries.  Could you elaborate?


----------



## glfporsche

I don't want to drag us too far from Pen's mods; but to answer a few questions:  My secondary air tubes are in fact 3/4 inch.  The baffle is McMasterCarr part number 93595K73.  It is a ceramic board made of aluminia and silica.  It has the consistancy of foam, very low density and soft, but it can take 2300 degrees F, and is a very poor conductor which means it reflects heat back into the fire box.  It is mounted at an angle, which I regret as it makes it harder to get the wood pushed all the way back.  The baffle is about 4 inches from the inlet of the stove pipe.  

To comment on Pen's conserns on adding more secondary air, and that leading to overfire.  I actually believe that you can add more secondary air right at the top of the baffle and this will burn off the smoke but will not increase your temps all that much, and not increase your burn rate.  The bulk of the air that's injected right at the baffle does not seem to get down to the main fire and thus does not seem to increase the burn rate.  

I more than quadroupled my secondary air supply when going to the stainless tubes.  I use a little less primary air now but not four times less, and the burn rate is about the same.  Actually, I find it harder to overfire now.  

I've updated with some flame picts:  http://glfporsche.smugmug.com/gallery/6450885_NdHjA

If you look closely, the picts at the bottom are with the stainless tubes and much increased secondary air.  You can see a contionus ribbon of flame coming off the rear most tube.  The secondary air enters the at the passage welded (poorly) to the side of the stove.   

Kris


----------



## glfporsche

Rick,

Yea, I think you got it.  I think my Lopi I an insert version of the stove you are talking about.  It's a beast!

Kris


----------



## brooktrout

I just wanted to say congrats on modifying your stove and especially for getting so many responses and ideas. All three times I tried to bring this up all I got were a bunch of pessimists saying don't mess with your stove.


----------



## Peter B.

Hogwildz wrote:

>Mayer I am misunderstanding. 
>Pen just stated he is not drawing the secondary air from the exhaust flue 
>if I read it correctly, but from an outside source separate from the 
>exhaust. That I can understand. 
>Is this drilling you speak or separate from the exhaust gases? Just curious.

I think you did misunderstand me, Hogwildz.

--

This still seems relevant to the thread so... I offer this simple example, which (I think) illustrates the idea.

If you drill a hole in your flue pipe and you have adequate draft, room air will be drawn into the flue through the hole.

If you put a tube of some kind partway through the hole in the flue (and the fit is tight), the tube will draw room air into the flue.

If you extend the tube through the hole in the flue down into the stove, it will still draw air... into the stove.

The extended tube will have at least a minimal heating effect on the air flowing through it.  This is, in effect, a very primitive secondary air supply.

It also avoids drilling holes in the stove itself... which pen said he was reluctant to do.

In my case, instead of drilling through the flue, I used an existing hole near the stove outlet flange (one of three such holes that originally could be opened or closed to help slow an overdraft).  I sealed this hole to a 3/4" copper elbow (open to the room), and added a length of copper tube down into the stove.  Again it's a rather primitive arrangement, but in fact, it helps some.  My stove doesn't have a glass door, so I can't see what's happening inside, but with all other drafts closed, under the right conditions, I can hear flame igniting from the air fed through the secondary.

Peter B.

-----


----------



## Peter B.

brooktrout said:
			
		

> I just wanted to say congrats on modifying your stove and especially for getting so many responses and ideas. All three times I tried to bring this up all I got were a bunch of pessimists saying don't mess with your stove.



There seem to be enough of us here interested in keeping our older stoves alive that the Moderators might consider another forum 'Room' strictly for mods to pre-EPA stoves.

(Hint, hint.)

Peter B.

-----


----------



## brooktrout

Peter B. said:
			
		

> brooktrout said:
> 
> 
> 
> 
> I just wanted to say congrats on modifying your stove and especially for getting so many responses and ideas. All three times I tried to bring this up all I got were a bunch of pessimists saying don't mess with your stove.
> 
> 
> 
> 
> There seem to be enough of us here interested in keeping our older stoves alive that the Moderators might consider another forum 'Room' strictly for mods to pre-EPA stoves.
> 
> (Hint, hint.)
> 
> Peter B.
> 
> -----
Click to expand...

Here, here- well said! Throw another shrimp on the barby!


----------



## Hogwildz

pen said:
			
		

> Hogwildz said:
> 
> 
> 
> 
> Since you already have the angle iron framed out for the baffle, why not make a secondary baffle like PE and some other manufacturers make?
> 
> 
> 
> 
> Are you talking about a drilled baffle plate that would rest just below this one?
> 
> pen
Click to expand...


Kind of, its more of a box with an 1" or so space inside, then holes/jets along the front face and a few strategically placed along the bottom. You could put it in place of the baffle you have there, and have secondary/baffle all in one.  No added space taken up, or not much. You already have the angle framing for it there. Then you just ened a way to get air to it. PE's have a vertical channel inside on the back of the firebox. I am sure you could drill/tap some sort of hole with control in such a channel.


----------



## Hogwildz

Peter B. said:
			
		

> Hogwildz wrote:
> 
> >Mayer I am misunderstanding.
> >Pen just stated he is not drawing the secondary air from the exhaust flue
> >if I read it correctly, but from an outside source separate from the
> >exhaust. That I can understand.
> >Is this drilling you speak or separate from the exhaust gases? Just curious.
> 
> I think you did misunderstand me, Hogwildz.
> 
> --
> 
> This still seems relevant to the thread so... I offer this simple example, which (I think) illustrates the idea.
> 
> If you drill a hole in your flue pipe and you have adequate draft, room air will be drawn into the flue through the hole.
> 
> If you put a tube of some kind partway through the hole in the flue (and the fit is tight), the tube will draw room air into the flue.
> 
> If you extend the tube through the hole in the flue down into the stove, it will still draw air... into the stove.
> 
> The extended tube will have at least a minimal heating effect on the air flowing through it.  This is, in effect, a very primitive secondary air supply.
> 
> It also avoids drilling holes in the stove itself... which pen said he was reluctant to do.
> 
> In my case, instead of drilling through the flue, I used an existing hole near the stove outlet flange (one of three such holes that originally could be opened or closed to help slow an overdraft).  I sealed this hole to a 3/4" copper elbow (open to the room), and added a length of copper tube down into the stove.  Again it's a rather primitive arrangement, but in fact, it helps some.  My stove doesn't have a glass door, so I can't see what's happening inside, but with all other drafts closed, under the right conditions, I can hear flame igniting from the air fed through the secondary.
> 
> Peter B.
> 
> -----



That makes perfect sense , and now I know I misread.
I completely agree now that I understand. I myself would be a lil hesitant to drill into the fuel pipe, in case of chimney fire etc.
But that is a personal preference, which each has their own.
I commend you guys with the older stoves and coming up with designs to help them burn better and more efficient.
I personally still think a baffle design similar to PE's and a couple other manufacturers will take up a lil less firebox space by doing the job of both baffle & secondary burn tubes all in one.
And honestly, I pack my stove to the gills. Many times up against the bottom of the baffle. I would prolly bend the tubes since I am used to the stainless baffle box up there. I admit I may have to get used the the tubes once I get the Englander I have sitting here installed and running along with the Summit also fired up. There best be no lack of heat at that point.
If my old Fuego Flame wasn't such a POS, I would toy with baffle/secondary design in it. But its junk and more suited to make a smoker of some sorts, or scrap when steel goes back up.
Keep us posted on the progress, and thanks for your patience in helping me understand what you meant.


----------



## Peter B.

pen wrote:

>While I love the added heat gained from my wood, what I am not happy with 
>is my flue gases.  I now have smoke  I never did before except for 
>about 10 minutes after a reload.  From then on out, it would be nothing 
>but heat waves.  Now, I am getting 30mins on an average load to 60-75 
>minutes on an overnight load of white smoke from the chimney.  All the 
>while the stove is producing killer heat and the chimney is about 350 
>degrees (normal).

...and...

>I have discussed the smoking issue with the metal shop buddy who built 
>this for me, and he believes even with the added smoking that I am going 
>to find less 2nd degree creosote in the chimney since I am no longer 
>needing to use my stove damper and the velocity of my flue gasses will 
>have increased.
> 
>Even if he is correct, the smoking issue bothers me from a smell 
>standpoint (I like my neighbors) and an environmental standpoint (no tree 
>hugger but I don’t like making a bigger impact than necessary).
>
>My thought is that a simple secondary, while it may not be perfect, may 
>add enough extra air in the back of this baffle to help better burn this 
>smoke I am finding. 

-- 

You've likely read this here before, but most people say white smoke that dissipates to the surrounding air quickly is likely (mainly) steam from the moisture in the wood.  If it's dark and lingers (and has any odor to speak of), that's 'real' smoke.

Again, I'm far from expert, but I'm inclined to think that yes, the secondary _should_ help burn off the 'added' smoke.

Also, I might continue to use the flue damper judiciously.  You don't really want a rapid velocity out of the stove proper... but rather a semi controlled 'reside time' within the stove to help mix volatiles, heat and air for complete combustion... before the exhaust enters the flue.

Peter B.

-----


----------



## WidowMaker

glfporsche said:
			
		

> I don't want to drag us too far from Pen's mods; but to answer a few questions:  My secondary air tubes are in fact 3/4 inch.  The baffle is McMasterCarr part number 93595K73.  It is a ceramic board made of aluminia and silica.  It has the consistancy of foam, very low density and soft, but it can take 2300 degrees F, and is a very poor conductor which means it reflects heat back into the fire box.  It is mounted at an angle, which I regret as it makes it harder to get the wood pushed all the way back.  The baffle is about 4 inches from the inlet of the stove pipe.
> 
> To comment on Pen's conserns on adding more secondary air, and that leading to overfire.  I actually believe that you can add more secondary air right at the top of the baffle and this will burn off the smoke but will not increase your temps all that much, and not increase your burn rate.  The bulk of the air that's injected right at the baffle does not seem to get down to the main fire and thus does not seem to increase the burn rate.
> 
> I more than quadroupled my secondary air supply when going to the stainless tubes.  I use a little less primary air now but not four times less, and the burn rate is about the same.  Actually, I find it harder to overfire now.
> 
> I've updated with some flame picts:  http://glfporsche.smugmug.com/gallery/6450885_NdHjA
> 
> If you look closely, the picts at the bottom are with the stainless tubes and much increased secondary air.  You can see a contionus ribbon of flame coming off the rear most tube.  The secondary air enters the at the passage welded (poorly) to the side of the stove.
> 
> Kris




====


Absolutely GREAT flame shots. Looks like you could be a consultant for the Devil and the Fires of He77...

Holy OVERSIZED 2ndary air jets....


I was with you till pict #25 thru 30, what is that part and where does it fit in side the stove, what function does it serve??


----------



## fossil

Peter B. said:
			
		

> ...There seem to be enough of us here interested in keeping our older stoves alive that the Moderators might consider another forum 'Room' strictly for mods to pre-EPA stoves.  (Hint, hint.)



Not the Moderators you need to try to convince about that, we're just janitors, and we serve at the pleasure of our beloved Webmaster, Craig Issod.  Put your idea in a post in The Suggestion Box forum, he's _really_ good about reading and responding to such things.  Rick


----------



## Peter B.

Rick:

Thanks for the heads up... I'll get to it.

--

Parenthetically, I might also ask Mr. Issod to 'tear down' this site... it's becoming addictive for me.

And I can't afford still another addiction.

Peter B.

-----


----------



## EddyKilowatt

Nice job on the baffle, Pen.   Interesting discussion about secondary air, also.

I have a pre-EPA, too -- a Jotul Model 8.  It's basically a big hollow box like Pen's Bear, but did come from the factory with a short-ish baffle made of cast iron.   My mods so far have been firebox insulation: I added a layer of ceramic wool (chimney liner wrap) on top of the baffle plate, and some more behind the cast-iron liner plates in the lower part of the firebox (where the Bear has firebrick in Pen's first post).   I'm a little concerned that higher operating temps will shorten the life of the cast parts, but in fact I believe that Jotul added similar insulation along the road toward cleaning up the Model 8 -- and I can report that it definitely burns hotter and cleaner with the hotter firebox.

So with that done,  I've been thinking about a secondary air retrofit, too, since I get more smoke than I'd like during the first third of each load, especially while dialing down the air.

There's a shop down the road from me that does stainless fab, and boat railings and stanchions in particular, in 316 stainless tube.  Since I have few metal fab skills of my own, I've been working with what they're good at.  My current plan is for a single piece of 1" OD tube, bent into the shape of a square-ish 'U' about two feet wide and one foot long, with both ends going thru holes I'll drill in the back wall of the firebox, just below the baffle.    I'm not eager to drill the stove, but I'd rather drill the rear wall (plain and out of sight) than the side walls (which have a cast-in patterns, and look really nice on the Jotul).  

I aim to have the main part of my secondary air tube, the two-foot-wide part that runs east-west, wind up a just under the baffle and a few inches back from the baffle's front edge.   I would be interested in any discussion of the optimum place to inject secondary air in a baffled firebox... I'm just going by what I've seen and used in other EPA stoves.

My big question concerns the number and size and orientation of the holes in the secondary tube.  All I can say so far is that I plan to start with a few small (1/16") ones aimed down about 45 degrees, and add them and enlarge them as I see how the burn looks.  So I would also be interested in any discussion regarding the optimum size and total area for secondary air injection... and what the tradeoffs are in terms of what happens if you inject TOO MUCH secondary air.

Great discussion so far!

regards,
Eddy


----------



## pen

glfporsche said:
			
		

> I don't want to drag us too far from Pen's mods; but to answer a few questions:  My secondary air tubes are in fact 3/4 inch.  The baffle is McMasterCarr part number 93595K73.  It is a ceramic board made of aluminia and silica.  It has the consistancy of foam, very low density and soft, but it can take 2300 degrees F, and is a very poor conductor which means it reflects heat back into the fire box.  It is mounted at an angle, which I regret as it makes it harder to get the wood pushed all the way back.  The baffle is about 4 inches from the inlet of the stove pipe.
> 
> To comment on Pen's conserns on adding more secondary air, and that leading to overfire.  I actually believe that you can add more secondary air right at the top of the baffle and this will burn off the smoke but will not increase your temps all that much, and not increase your burn rate.  The bulk of the air that's injected right at the baffle does not seem to get down to the main fire and thus does not seem to increase the burn rate.
> 
> I more than quadroupled my secondary air supply when going to the stainless tubes.  I use a little less primary air now but not four times less, and the burn rate is about the same.  Actually, I find it harder to overfire now.
> 
> I've updated with some flame picts:  http://glfporsche.smugmug.com/gallery/6450885_NdHjA
> 
> If you look closely, the picts at the bottom are with the stainless tubes and much increased secondary air.  You can see a contionus ribbon of flame coming off the rear most tube.  The secondary air enters the at the passage welded (poorly) to the side of the stove.
> 
> Kris



Great pics.  If I understand you correctly, do you think a secondary tube above the baffle (as in the upper chamber of the stove) would be effective?

If so, that would be wonderful as it would definitely not affect the size of my firebox.  I had counted this idea out because I didn't think it would be hot enough here?  Or that the secondaries needed to be directly into the flame?  I was afraid that a secondary in this area would mainly work to dilute to gasses but wouldn't be effective for creating combustion.

pen


----------



## pen

Peter B. said:
			
		

> pen wrote:
> 
> >While I love the added heat gained from my wood, what I am not happy with
> >is my flue gases.  I now have smoke  I never did before except for
> >about 10 minutes after a reload.  From then on out, it would be nothing
> >but heat waves.  Now, I am getting 30mins on an average load to 60-75
> >minutes on an overnight load of white smoke from the chimney.  All the
> >while the stove is producing killer heat and the chimney is about 350
> >degrees (normal).
> 
> ...and...
> 
> >I have discussed the smoking issue with the metal shop buddy who built
> >this for me, and he believes even with the added smoking that I am going
> >to find less 2nd degree creosote in the chimney since I am no longer
> >needing to use my stove damper and the velocity of my flue gasses will
> >have increased.
> >
> >Even if he is correct, the smoking issue bothers me from a smell
> >standpoint (I like my neighbors) and an environmental standpoint (no tree
> >hugger but I don’t like making a bigger impact than necessary).
> >
> >My thought is that a simple secondary, while it may not be perfect, may
> >add enough extra air in the back of this baffle to help better burn this
> >smoke I am finding.
> 
> --
> 
> You've likely read this here before, but most people say white smoke that dissipates to the surrounding air quickly is likely (mainly) steam from the moisture in the wood.  If it's dark and lingers (and has any odor to speak of), that's 'real' smoke.
> 
> Again, I'm far from expert, but I'm inclined to think that yes, the secondary _should_ help burn off the 'added' smoke.
> 
> Also, I might continue to use the flue damper judiciously.  You don't really want a rapid velocity out of the stove proper... but rather a semi controlled 'reside time' within the stove to help mix volatiles, heat and air for complete combustion... before the exhaust enters the flue.
> 
> Peter B.
> 
> -----



I now agree that it was mostly steam as a result of the ambient air.  (I noticed that when the furnace fired up to heat hot water while I was watching the wood stove chimney that it too had the same steam)  Essentially, duh   Just me being over paranoid!  However, the idea of including a secondary is still interesting and has created great conversation.

I would like to thank everyone for their open and most importantly _intelligent _conversation regarding this topic.  On many forums, that is tough to come by!

I think this shows that wood burners are inherently a different and perhaps even superior breed!

pen


----------



## jacksnipe

I'm trying to grasp ahold of all this info but am getting a bit confused about the secondary tubes etc. located above the baffle. Doesn't make much sense to me with it being located there, most of the mfg have it located under the baflle. I also wonder about the clearance issues between the baffle
top surface & the appliance flue oulet, is there a engineering spec in place for this fiqure. I saw that 4" was given on the design with the pictures of the wonderful secondary in operation, could this dimension be reduced to 2" to increase the usable fire box height. I'm also a bit reluctant to start drilling the firebox.


----------



## pen

I decided to make my baffle as tall as it is based upon the area of my 8 in flue pipe.  The opening left from the top lip of the baffle to to the bottom of that front plate leaves the same to a little more surface area as the flue so that I wouldn't have a issue smoking.  So far so good.  When I open the door, there is no smoke issue at all that comes into the house. 

This height also ended up so that the bottom of the baffle is approximately 1 1/2 inches above the top lip for the door.  You can't load the stove any higher than the door will allow when loading front to back, so this has not restricted the amount of wood that I put in the stove.  Although it has reduced the amount of wood that I need to put into the stove.  

Now, I made my baffle overlap the front lower area of my stove top by about a 1/2 an inch.  It sounds like the other person with a baffle brought it a bit closer to the front of the stove if I understand them correctly.

pen


----------



## Malatesta

Excellent job on the secondary tubes , And nice baffle Pen I have Grandma bear fisher to 1980 it has a baffle in it already. Kinda only a half baffle thou. The secondary tubes are a great idea. These old stoves are pretty indestructible. I was thinkng of running secondary tubes in mine . Same kinda set-up only running the air supply towards the back and Then down the back of the stove. Then maybe the air supply out the bottom.


----------



## jacksnipe

pen said:
			
		

> I decided to make my baffle as tall as it is based upon the area of my 8 in flue pipe.  The opening left from the top lip of the baffle to to the bottom of that front plate leaves the same to a little more surface area as the flue so that I wouldn't have a issue smoking.  So far so good.  When I open the door, there is no smoke issue at all that comes into the house.
> 
> This height also ended up so that the bottom of the baffle is approximately 1 1/2 inches above the top lip for the door.  You can't load the stove any higher than the door will allow when loading front to back, so this has not restricted the amount of wood that I put in the stove.  Although it has reduced the amount of wood that I need to put into the stove.
> 
> 
> 
> 
> Now, I made my baffle overlap the front lower area of my stove top by about a 1/2 an inch.  It sounds like the other person with a baffle brought it a bit closer to the front of the stove if I understand them correctly.
> 
> 
> 
> 
> pen
Click to expand...

 I'm at a loss here to understand what the distance is from the door opening to the front edge of the baffle. The Fisher Insert is of a little different design, in that it incorporates a flue type baffle plate that drops down when open so the top of the baffle will have to be probably 1 1/2" lower than this so it won't hit. I too like to run with the doors open on occasion to view the fire so I don't want it set off the smoke alarms.
 As of this point I have the tube materials in seamless 1" dia. 316 sst. & the manifold material, I have been on the McMaster Carr website looking at the baffle material which can be cut size the stove as needed. I haven't  got the nerve yet to drill a hole in a perfectly good stove to install the secondary air supply.


----------



## Bigg_Redd

pen said:
			
		

> Yamaha_gurl said:
> 
> 
> 
> 
> So, a baffle is only a plate that prevents all the flames from going up the chimney? Sorry, newbie alert :red: If so, I'm lucky...my fisher already has one :D
> 
> 
> 
> 
> Funny you mention that.  My buddy who has a grandma bear "like" stove built by kodiak had a smoke shelf as well.  This one simply did not.
> 
> Any chance you could take a picture of yours?  I am curious to see what it looks like.
> 
> pen
Click to expand...


My parents have a Kodiak made Fisher knock off insert with a baffle.


----------



## kksalm

This is a wonderful thread. What I've been wanting to do is convert my fireplace into something like glfporsche's wood stove. All I need is a good airtight stove door with an accompanying framework to seal the front of my fireplace. I would make a suspended baffle complete with the hanging secondary burn tubes out of steel and incorporate high tech fire brick to complete the stove rather than build the rest with steel. More or less a masonry stove using the principles being described in this thread. My fireplace has ample room to build a masonry stove inside of it and contains lots of mass to retain the heat. Thanks all for an inspiring thread.
Best regards, kksalm


----------



## pen

jacksnipe said:
			
		

> pen said:
> 
> 
> 
> 
> I decided to make my baffle as tall as it is based upon the area of my 8 in flue pipe.  The opening left from the top lip of the baffle to to the bottom of that front plate leaves the same to a little more surface area as the flue so that I wouldn't have a issue smoking.  So far so good.  When I open the door, there is no smoke issue at all that comes into the house.
> 
> This height also ended up so that the bottom of the baffle is approximately 1 1/2 inches above the top lip for the door.  You can't load the stove any higher than the door will allow when loading front to back, so this has not restricted the amount of wood that I put in the stove.  Although it has reduced the amount of wood that I need to put into the stove.
> 
> 
> 
> 
> Now, I made my baffle overlap the front lower area of my stove top by about a 1/2 an inch.  It sounds like the other person with a baffle brought it a bit closer to the front of the stove if I understand them correctly.
> 
> 
> 
> 
> pen
> 
> Click to expand...
> 
> I'm at a loss here to understand what the distance is from the door opening to the front edge of the baffle. The Fisher Insert is of a little different design, in that it incorporates a flue type baffle plate that drops down when open so the top of the baffle will have to be probably 1 1/2" lower than this so it won't hit. I too like to run with the doors open on occasion to view the fire so I don't want it set off the smoke alarms.
> As of this point I have the tube materials in seamless 1" dia. 316 sst. & the manifold material, I have been on the McMaster Carr website looking at the baffle material which can be cut size the stove as needed. I haven't  got the nerve yet to drill a hole in a perfectly good stove to install the secondary air supply.
Click to expand...


Stove is burning and I am not going to stick the measuring tape in there now.  I didn't worry about the distance from the door but rather just a 1/2 in overlap of the front lower top plate of the stove.

Maybe this will help

pen


----------



## WES999

A few thoughts on baffles. When I was designing the modifications for my Fisher stove, one of the first things I did was to study as many of the online stove manuals I could find, look at the Englander NC-30 manual, it shows the size,number and orientation of the air holes. Note how the holes in the rear ( closest to the air supply are smaller than the holes in front) to balance the flow. The baffle design in the Englander seems to be the most common and wildly used. I have attached some drawings of my stove so you can see how I made my baffle and secondary air tubes.


----------



## bokehman

Pen, your secondary air needs to be injected below the baffle. That is the hottest point. Above the baffle won't be efficient. 

Regarding whether or not the secondaries are necessary the answer is they are. If you look at the photos of the Lopi modification there is flame at the secondaries. If they weren't necessary there would not be flame there.


----------



## Malatesta

Wes how do the secondary air tubes get there air supply ? I tried to max out the pics it was tuff to see.


----------



## jacksnipe

Pen: Thanks for the drawing that shows the baffle outline. I can see why it doesn't smoke much, In your original photograph of the baffle assy. it looked much closer to the door opening. I forgot about the 2 step design of the stove where the front half is lower,  the insert model has a flat top all the way from the front to the rear. So I'm guessing here that the set back for the front of the baffle would be about the width of 2- 3  of the vertical side  firebricks = about  9" - 12" from the door opening. The rest of the measurements you noted would follow in line to utilize the baffle in the insert.
 Note: The firebox size for the insert is 18" wide x  26" deep, the front edge of flue opening with the damper plate is 18" from the door opening. I'm seeing other designs also that show this baffle unit mounted at a slight angle, I'm curious if this is necessary


----------



## pen

bokehman said:
			
		

> Pen, your secondary air needs to be injected below the baffle. That is the hottest point. Above the baffle won't be efficient.
> 
> Regarding whether or not the secondaries are necessary the answer is they are. If you look at the photos of the Lopi modification there is flame at the secondaries. If they weren't necessary there would not be flame there.



Good point.

That is what I was assuming but wanted to double check after reading the comments of the one individual.

As far as the true necessity what I really should have said is "will it be worth my while."  There is no doubt that they will improve efficiency but with my setup and means, I am just trying to figure how much more I would truly gain and if it would be worth the effort.  Considering the heat gain I am seeing and the less wood I am using, the only other concern for me is chimney cleanliness.  If my chimney is not as clean or cleaner than it usually is after one month, then I will take the next step.  Otherwise, I am not sure if the risk involved with modification plus diminishing the size of the usable firebox would be worth it.  

pen


----------



## pen

jacksnipe said:
			
		

> Pen: Thanks for the drawing that shows the baffle outline. I can see why it doesn't smoke much, In your original photograph of the baffle assy. it looked much closer to the door opening. I forgot about the 2 step design of the stove where the front half is lower,  the insert model has a flat top all the way from the front to the rear. So I'm guessing here that the set back for the front of the baffle would be about the width of 2- 3  of the vertical side  firebricks = about  9" - 12" from the door opening. The rest of the measurements you noted would follow in line to utilize the baffle in the insert.
> Note: The firebox size for the insert is 18" wide x  26" deep, the front edge of flue opening with the damper plate is 18" from the door opening. I'm seeing other designs also that show this baffle unit mounted at a slight angle, I'm curious if this is necessary


]

The dimensions of my baffle are 22 wide and 12 inches deep.  The height is 5 1/4 to the bottom of the firebrick in the baffle from the top of the firebrick in my box.  This makes for  6 1/2 total height above the firebrick.  I couldn't make my baffle any deeper than 12 inches because of the table design that I made.  If I made it deeper, the metal angle iron firebrick retainers on the sides of the stove would have been in the way.  

I think that the sloping feature of the other baffles were due to the rear exit whereas my stove is a top exit flue.

At least one individual who posted here mentioned that they wish they had not sloped their baffle.  

pen


----------



## BJ64

This is a great thread.

It makes me want to buy some of the old stoves such as a Schrader and what ever else is available and mod them like this for the shop, my buddy's shop, the brother-in-law's shop....  

Anyway, great thread.


----------



## ScottF

Great thread, I have read it with great interest.  I have an antique stove similar to Peter Bs that we use to heat the entire house and we only heat with wood.  I would like to add to Peter B,s request for a section of the forum set aside for antique stove modifications.  I would love to see a proven plan for modifying an old cylindrical parlor stove.  thanks for all the good information.


----------



## Redox

BJ64 said:
			
		

> This is a great thread.
> 
> It makes me want to buy some of the old stoves such as a Schrader and what ever else is available and mod them like this for the shop, my buddy's shop, the brother-in-law's shop....
> 
> Anyway, great thread.



Know what you mean!  I gave away my old Fisher and now I'm wondering if I can get it back.  

I THOUGHT I heard some secondary air tubes rattling around out there in this thread!

Chris


----------



## WES999

Woodcrib said:
			
		

> Wes how do the secondary air tubes get there air supply ? I tried to max out the pics it was tuff to see.



It is hard to see in the drawings.  Check out this thread, near the bottom, there is a pic and a description of the secondary air intake.
https://www.hearth.com/econtent/index.php/forums/viewthread/17993/


----------



## Peter B.

ScottF wrote:

>I would like to add to Peter B,s request for a section of the forum set 
>aside for antique stove modifications.

--

I've now posted a suggestion for similar to (where else) 'The Suggestion Box' titled "Pre-EPA 'Room' ?"

https://www.hearth.com/econtent/index.php/forums/viewforum/8/

Pile on if any of you would like to see a separate forum section for this kind of topic.

Peter B.

-----


----------



## ScottF

> I’ve now posted a suggestion for similar to (where else) ‘The Suggestion Box’ titled “Pre-EPA ‘Room’ ?”
> 
> https://www.hearth.com/econtent/index.php/forums/viewforum/8/
> 
> Pile on if any of you would like to see a separate forum section for this kind of topic.
> 
> Peter B.



Thanks Peter.  I piled on.


----------



## brooktrout

I voiced my support as well. Let's hope Craig follows through. There are thousands of "classics" still burning out there. We deserve a voice!


----------



## crazy_dan

Is your stove cast or plate steel?
If it is plate I would just cut a hole in the bottom in the rear of the fire box and notch out the fire brick and run my pipe/ secondary air supply up from the bottom of the stove and it would get heated in the fire box as a bonus. that is how PE does it anyway and it works great on my summit. if it is cast it can still be done done but needs a much higher level of welding experience than most novices have. I don't know that I would go adding anything to the flew as it would decrease the area of the flue and could affect the drafting of your stove IE like putting it to a 6" flue instead of a 8". 

looks like you did a great job. congrats


----------



## mellow

glfporsche said:
			
		

> I more than quadroupled my secondary air supply when going to the stainless tubes.  I use a little less primary air now but not four times less, and the burn rate is about the same.  Actually, I find it harder to overfire now.
> Kris



How much $$ do you have into converting your lopi to secondary?

Also, you kept the steel for the sides where the tubes mount into instead of going to stainless for them as well?

I was trying to figure out how hard it would be to weld stainless to the steel.


----------



## hydrology_joe

I am planning to attempt this modification on my Fisher next summer and am looking to begin collecting parts now.  Any ideas where to obtain some of those 5pt star dampers?  (other than hacking them off another stove)


----------



## pen

For those of you interested........

Been 4 weeks burning the stove with the baffle installed.

The results as far as additional heat output, extended burn time, and overall being more controllable, and using less wood have been outstanding.  I have seen improvement in every way possible.

So far that baffle seems to be holding up to the stresses of living inside the firebox.  No wear is visible.

The last item to determine would be the cleanliness of my chimney.

Being that I have a short to medium height and exterior brick / terracotta lined chimney, I decide that it is best that I clean it every 4 weeks (the old standard for my smoke dragon era stove and chimney).  I burn appropriately seasoned beech, hard maple, cherry and ash.  

Stove burns nearly 24/7.  Some days it is a near cold start when getting home from work.  

After burning this month I have essentially the same build up as I always do.  About 1 quart of the medium flaky, dusty, med - dark colored, typical creosote for my style of chimney.

With that said, the baffle is staying in the stove.  Using the stove the past month has been more enjoyable than ever due to the increased predictability of the stove.  I no longer am using my chimney damper and find very little difference in the quality of the burn because of varied weather and/or temperature.  This was not the case before.  Previously, the stove could be a little bit surprising at times in its reactions to adjustments and loading.  That is not the case now. 

Life is about as good as it gets for one of these old girls (shy of adding secondaries that is).

Because of the chimney being about as clean as normal, I am not going to mess around with adding secondaries at this time.  Perhaps this summer when the stove isn't in daily use I'll get the itch to mess with it.

I wouldn't want to put the old girl up against many of your new stoves in terms of efficiency, but I can guarantee that this baffle has greatly increased the amount of usable heat that the stove produces per load.  

Thanks again to everyone for their support and suggestions.

Happy burning,

pen


----------



## jacksnipe

pen said:
			
		

> For those of you interested........
> 
> Been 4 weeks burning the stove with the baffle installed.
> 
> The results as far as additional heat output, extended burn time, and overall being more controllable, and using less wood have been outstanding.  I have seen improvement in every way possible.
> 
> So far that baffle seems to be holding up to the stresses of living inside the firebox.  No wear is visible.
> 
> The last item to determine would be the cleanliness of my chimney.
> 
> Being that I have a short to medium height and exterior brick / terracotta lined chimney, I decide that it is best that I clean it every 4 weeks (the old standard for my smoke dragon era stove and chimney).  I burn appropriately seasoned beech, hard maple, cherry and ash.
> 
> Stove burns nearly 24/7.  Some days it is a near cold start when getting home from work.
> 
> After burning this month I have essentially the same build up as I always do.  About 1 quart of the medium flaky, dusty, med - dark colored, typical creosote for my style of chimney.
> 
> With that said, the baffle is staying in the stove.  Using the stove the past month has been more enjoyable than ever due to the increased predictability of the stove.  I no longer am using my chimney damper and find very little difference in the quality of the burn because of varied weather and/or temperature.  This was not the case before.  Previously, the stove could be a little bit surprising at times in its reactions to adjustments and loading.  That is not the case now.
> 
> Life is about as good as it gets for one of these old girls (shy of adding secondaries that is).
> 
> Because of the chimney being in good shape, I am not going to mess around with adding secondaries at this time.  Perhaps this summer when the stove isn't in daily use I'll get the itch to mess with it.
> 
> I wouldn't want to put the old girl up against many of your new stoves in terms of efficiency, but I can guarantee that this baffle has greatly increased the amount of usable heat that the stove produces per load.
> 
> Thanks again to everyone for their support and suggestions.
> 
> Happy burning,
> 
> pen


 This is great news to hear that the baffle is working better than anticipated, I have been waiting for a report on your burning with the new modifications in place. Since you report that the stoves runs hotter & longer with less wood, are you finding that you can decrease the amount of primary air also & still maintain decent stove top temps especially during these extreme temps we are facing now. I'm curious at what your primary setting is during the day while your away..
 I can't wait for spring to arrive, so I can get started on our unit, I'm thinking along the lines of using the high temp ceramic fiber board instead of a firebrick baffle. It would seem easier to remove before the chimney needed to be cleaned,


----------



## pen

Surprisingly, the settings of my dampers are the same as they were before.  What I am finding is that the only difference is that it stays hotter, longer.

Here is my strategy.

My "max" heat setting for a high burn is when I set my drafts at 1 1/4 turn open each.

For a normal "I am home and it's chilly out" burn, I open the drafts 1 turn each.  This usually results in about a 6 hour burn using hardwoods.

For overnight I close it no more than 3/4 of a turn open on each.  This will let me go up to about 9 hours while leaving me ample coals to restart from using standard sized splits.

These obviously are dependent upon the force of my chimney draft, how tight my basement is, the type of wood I am burning, the size of my splits, etc, etc.  Most anyone else in the universe's results will vary 

It was extremely cold the other night (I wish I had borrowed my buddies infrared temp gun) and i wanted to get a maximum setting idea to give to the Mrs.  (I have a thermometer on the slanted step between the lower and upper shelf's of the stove and another on the single wall stove pipe).  The lady likes numbers to work with (and I am a bit of a geek as well).

I found that at 1 and 1/2 turns open on each draft I could reach about 650 degrees on the thermometer as measured right of center on this slanted step portion.  (not the hottest part of the stove but is the most convenient location.  I am going for consistency here, not a max stove-top temp)  At this temp, I began to get a very dull "red glow" in an area about the size of 2 packs of cigarettes on the back of the stove.  This could only be seen with all the lights turned off and eyes given a minute or two to adjust.  When looking at the stove with nearly 30 years of burning on her, this is apparently the traditional hot spot as is evidenced by an ever so slight "bow" outward and a lighter color than the rest of the stove.  

Also, with the thermometer here, I can reload perfectly every time when the temp gets down to about 175.  At that temp, I have just enough coals to relight things without using kindling.

Nothing like being an analytical dweeb   I like measurements.  Does that make me a bad person?

pen


----------



## jacksnipe

Your draft setting are idenical to mine, both 3/4 open for cool ( 20 - 30 degree ) weather for overnight burning &  1 -  1 1/2 Open for daytime running at 650 stove top temp. I have never witnessed a dull glow on any part of the stove however, but I'm thinking now that installing a new baffle may change some temps inside the firebox. I have found that running the drafts at 3/4 open that I can achieve 8 - 9 hours but the stove has cooled off way to much for my liking. If I run it at 1 1/4 open it will run 6 - 7 hours & be at 350 stove temp at the end of this time. If I could manage to get this unit to run 400 stove top for 7 hours that would be like a winnning lottery ticket


----------



## pen

I would still like to know why some of these stoves and inserts came with a smoke shelf and others did not.  


pen


----------



## jacksnipe

Good question, I've seen the stoves both ways , with & without the steel plate smoke shelf baffle. But I have yet to see the insert model with any type of baffle shelf, probably because they  incorporated the damper plate at the flue opening ?  Now the Honey Bear model with the beautiful glass doors may have something installed that I haven't been notified about..


----------



## pen

yamahaurl has the honey bear and says she has a smoke shelf.  

When seeing them in the past, I really hadn't paid too close attention.  If i remember correctly, they were pretty much entirely contained in the upper shelf of the stove correct?

I asked yamahaurl for a pic of hers but she might not have seen the request or might not be able to.

I am curious to get the standard dimensions from the manufacturer for what they used and what was UL approved (for some of the later models).

Mine unfortunately is not UL approved.  This actually works out to my advantage however for modification.  I had to search for a homeowners insurance company that would allow me having a non-UL stove.

pen


----------



## Yamaha_gurl

You can just see it, hope I didn't burn my camera lens!


----------



## pen

Yamaha_gurl said:
			
		

> Give me 2 minutes pen!



  Outstanding!


----------



## Yamaha_gurl

And one more:






It to me doesn't seem like someone did this, rather right out of the factory.


----------



## pen

I agree, looks factory too me.

Those are perfect pics!  (Healthy sized log you have there BTW)

Thanks for sharing that and sacrificing your camera for the purpose of good BS!

pen


----------



## Yamaha_gurl

pen said:
			
		

> I agree, looks factory too me.
> 
> Those are perfect pics!  (Healthy sized log you have there BTW)
> 
> Thanks for sharing that and sacrificing your camera for the purpose of good BS!
> 
> pen



Yes, I agree good sized log. I actually was curious as to what size my box was, so I measured (length x width x height...right? ) today. 2.3 cubic feet. I guess that's average right? I can't believe that no one has heard of the honey bear stove. I hear about baby bears, but never honey :-S

That was pure luck on your part Pen that I just stumbled on this post again...lol. :D


----------



## jacksnipe

Wow, what am I seeing here  another set of angles  above the brick retainers front to back. To much smoke & fire to decipher this design, Is the baffle a sheet of steel plate?  Stove or Insert ? I have several questions regarding dimensions of this design


----------



## Yamaha_gurl

jacksnipe said:
			
		

> Wow, what am I seeing here  another set of angles  above the brick retainers front to back. To much smoke & fire to decipher this design, Is the baffle a sheet of steel plate?  Stove or Insert ? I have several questions regarding dimensions of this design




It is a steel plate, and it's a Fisher, honey bear wood stove  What questions do you have?


----------



## pen

looks to me like a piece of boiler plate with a lip on the front facing down.

Also looks like the 2in area that I left above my baffle they left in-front of theirs.

pen


----------



## Yamaha_gurl

pen said:
			
		

> looks to me like a piece of boiler plate with a lip on the front facing down.
> 
> Also looks like the 2in area that I left above my baffle they left in-front of theirs.
> 
> pen




That is true, there is about2-3 inches in the front.  I couldn't really tell you what type of steel it is...I am only just a little woman


----------



## jacksnipe

Yamaha_gurl said:
			
		

> jacksnipe said:
> 
> 
> 
> 
> Wow, what am I seeing here  another set of angles  above the brick retainers front to back. To much smoke & fire to decipher this design, Is the baffle a sheet of steel plate?  Stove or Insert ? I have several questions regarding dimensions of this design
> 
> 
> 
> 
> 
> It is a steel plate, and it's a Fisher, honey bear wood stove  What questions do you have?
Click to expand...

 I would assume this is a top outlet stove model, if so, How high above the brick retainers does the baffle plate sit & what is the length & width of the baffle plate. Wait until the stove cools down before you do any measuring...
 Pen Mentioned something about a bent lip on the front edge toward the door opening, is this to help keep the smoke down in the firebox.


----------



## pen

Yamaha_gurl said:
			
		

> pen said:
> 
> 
> 
> 
> looks to me like a piece of boiler plate with a lip on the front facing down.
> 
> Also looks like the 2in area that I left above my baffle they left in-front of theirs.
> 
> pen
> 
> 
> 
> 
> 
> That is true, there is about2-3 inches in the front.  I couldn't really tell you what type of steel it is...I am only just a little woman
Click to expand...


Yea,

Just a lil' woman who has no problem with a wood stove and will stick her head into one jeopardizing life, limb and camera for "the shot" just to keep the conversation going!

That's pretty good as well as above and beyond the call!

pen


----------



## Yamaha_gurl

jacksnipe said:
			
		

> I would assume this is a top outlet stove model, if so, How high above the brick retainers does the baffle plate sit & what is the length & width of the baffle plate. Wait until the stove cools down before you do any measuring...
> Pen Mentioned something about a bent lip on the front edge toward the door opening, is this to help keep the smoke down in the firebox.



Top outlet you mean stove pipe going straight out the top correct? If so, yes.

I will measure tomorrow morning...I never have coals for overnight burns


----------



## pen

Well, I think I am changing my mind as we speak about what I am doing with this baffle.

I found aspot on the stove that is "glowing" with a normal burn style fire going on.

I am afraid that by building my baffle as far forward as I did (bringing it into the front shelf) that I am forcing too much heat to go along that front top plate on its way to exit.

I happened to be up early this morning wandering the house and went down in the basement to relax by the warm stove.  For some reason the little blue light on the satellite box wasn't on (must have had the power flicker) and I can just barely see glowing red on the center of that front part of the top plate.

What baffles me (pardon the pun) is that when I move my stove top thermometer to the area it is only registering about 700 degrees.  I know it is accurate to 600 as it was compared to a IR thermometer just recently.  Does metal cherry faster or at a lower temp if it has been heated continually over the years?

I can't in my mind see how my setup is stressing that top plate anymore than what yamahaurl showed us with her baffle in her honey bear, but I perhaps it is.

I am going to try removing the smallest (width-wise) firebrick form the front of the baffle and pulling the bricks together, making a bit of an escape on either side of that front row.  

I'll just need to wait for the old girl to cool and the experimentation will begin all over again.

I am absolutely dumbfounded how that 1/4 in steel top plate has some color too it yet will only read about 700 on the thermometer.  I hear some of you guys pulling 750 on a stove stop?!?  Why is mine turning into a light bulb and yours isn't?  I would think that your top plates would be subjected to a higher degree of a beating considering the secondary burn.

Who knows, maybe I shouldn't even be concerned.  After all, that top plate isn't really going to go anywhere.  And its not like I have a stove that is assembled with gaskets like many others to be concerned about warping.  The stove pipe temps are staying right in range too.  Ah, there I go trying to rationalize again.  

Any and all thoughts for the sake of discussion are welcome and encouraged of course.  

Damn this irritates me as the results have been so good.  ugh.  

pen


----------



## pen

CZARCAR said:
			
		

> firebrix on top results in hotter firebox for next load & if inadequate combustion air results, the pyrogas will go up the chimney unburnt. epa stove has secondary air ,preheated , & brought in on top so that the hot firebox which is boiling off gases from the wood actually ignite as the secondaries flame up. the burn is cleanly extended from combustion air not being directly introduced into load.
> steel baffle will heat & cool quicker so that firebox will not remain as hot. both will prevent smoke from going straight out the chimney so the retention will enhance mixing of air & pyrogas for better combustion.still , if the load is offgassing too much for available amount of combustion air, the gas cant burn fully



I believe I follow what you are saying here in that using the baffle with out secondaries may result in unburned wood gases going up the chimney.  Perhaps my baffle is too efficient and I would be better off removing one of the front brinks to allow the fire to cool a bit and not out-gas so much.  

Are you just making an observation here or would this have any effect on my situation with the stove turning into a small lightbulb ?

pen


----------



## pen

I wonder too if this could be a result of it being -10 for the last two night.  Perhaps I haven't seen this before because I haven't seen this hard of a draft draw?

That could create a catch 22.  If the increase draft is causing me to overburn, I could reduce draft using the damper, but that would keep more heat in the stove also!

Maybe I am just running too much primary air for this cold weather, but didn't think about it as my chimney temp is staying about 400-450 (where I like it) and I am still getting the burn times I expect.

Who knows.

pen


----------



## Yamaha_gurl

Sorry Pen, can't help you out there, and I can't measure anything cause bf woke up before me and started a fire %-P


----------



## jabush

pen said:
			
		

> CZARCAR said:
> 
> 
> 
> 
> firebrix on top results in hotter firebox for next load & if inadequate combustion air results, the pyrogas will go up the chimney unburnt. epa stove has secondary air ,preheated , & brought in on top so that the hot firebox which is boiling off gases from the wood actually ignite as the secondaries flame up. the burn is cleanly extended from combustion air not being directly introduced into load.steel baffle will heat & cool quicker so that firebox will not remain as hot. both will prevent smoke from going straight out the chimney so the retention will enhance mixing of air & pyrogas for better combustion.still , if the load is offgassing too much for available amount of combustion air, the gas cant burn fully
> 
> 
> 
> I believe I follow what you are saying here in that using the baffle with out secondaries may result in unburned wood gases going up the chimney.  Perhaps my baffle is too efficient and I would be better off removing one of the front brinks to allow the fire to cool a bit and not out-gas so much.  Are you just making an observation here or would this have any effect on my situation with the stove turning into a small lightbulb ?pen
Click to expand...



I think you are on the right track as far as removing one of the thinner bricks and allowing additional space at the sides of the baffle to let the hot gasses escape.  Right now you are focusing all that hot gas on one part of the stove.  If you open up some space around the baffle to disperse the heat a little, the glowing may stop.FWIW...I routinely run my stove top thermo up to 700+ (with stack temps in the 800-900 range)in preparation for overnight burns, and I've never noticed any glowing.  There is however a very slight warp on the back panel of my cabinet, which is where all the hot gasses are forced around the baffle.


----------



## jabush

pen said:
			
		

> I would still like to know why some of these stoves and inserts came with a smoke shelf and others did not.
> 
> 
> pen



I think this had to do with the high demand for these stoves when they were first made.  Bob Fisher subcontracted to many fab shops around the country to make the Bears.  I imagine some shops included the baffle and others did not.


----------



## bokehman

pen said:
			
		

> I can just barely see glowing red on the center of that front part of the top plate.


750F. Obviously if you modify the stove and change the air currents inside you will change the areas that get hottest but I wouldn't worry about it and I certainly wouldn't remove any of the baffle that's making it run so well.


----------



## jacksnipe

Pen: I would like to see some results of running the stove with both drafts set at 1/4 - 1/2 open during these extreme cold spells. If the chimney is pulling real hard during sub zero weather this may help or a damper might work also. If we could get these units to run at a 1/2" open draft setting
during a real cold spell like this & maintain high stove temps, it's all gravey


----------



## karri0n

Ressurecting this thread due to precaud's thread. Pen, did you ever go ahead with the secondary idea? Is it still in the works, or are you scrapping it, or is it just on hold due to other projects? I'm quite interested in seeing your results.


----------



## pen

I removed a brick and allowed about 3/4 of an inch of space along the side of the bricks in the baffle and this took care of overheating the front of the stoves top plate.  The stove is burning great, I am using much less wood, and the chimney is not accumulating anything more than normal.  With that said, I am very happy with the results and haven't gone any further in playing with the idea of secondary air.  Maybe down the road.  

pen


----------



## Rebel Wood

My father in law had an early Grandpa Bear with no provisions for a baffle,maybe later versions did. His stove dated from the mid-seventies. My Hutch Rebel had angle supports welded to the sides to support a baffle. Recent baffle changes have made a huge difference as you describe. Existing, but inactive water coil will be coming out to install secondary burn tube per your drawings. Since I made the stove penetrations 20 plus years ago, and the one is in the perfect location, I have nothing to lose. Pictures of progress forthcoming. Thanks for the inspiration.


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## jacksnipe

Pen: This is great news to hear that you have tamed the stove down to a milder condition. I will incorporated your update to my final design for the baffle in the fisher insert. I never heard back from the Gal the runs the Honey Bear model on the dimensions of the stock baffle that was originally
installed in some of these models. I will continue to monitor this thread for futher updates from all users considering this modification in their units.
 I Can't wait for spring time to roll around so I can yank out the insert & install a full block off plate on top & all around the back & sides. I loose way to much heat up the chimney & being a brick fireplace on an exterior wall it's not an ideal situation..


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## cottonwoodsteve

DYI ideas;
For air tubes, look at propane grill replacement burner tubes. The holes may need to be drilled out a little
One of these thin stailess tubes will last much longer than a s regular thick steel pipe.
They are about $10 at the big box hardware stores.
If you use regular pipe, use "black" gas pipe. Do not use galvanised water pipe. The zinc coating is poisones when it burns.
When you get things designed correctly then order some thicker stailless pipe and do it right.
Regular steel will appear to quickly rust away in extreme heat.
For long term but still temporary protective heat coatings, use muffler patch with the liquid or cream. The two types act different.
Experiment!


Other ideas;
Also mess with a simular air system on the bottom of the fire. Angle bricks in so the fire and coals shift to the center as things burn. 
This prevents something from just smoldering over in the corners.
The "in" thinking is burning the smoke after it forms. But you can also burn things better so they don't make smoke in the first place.
Look at making a pellet stove type system. But make it burn split log size pellets :>)
Do pellet stoves have an afterburner system? No, they burn the wood correctly the first time and don't have a smokey mess the burn off.


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## TX-L

Here is what I did last year:  https://www.hearth.com/econtent/index.php/forums/viewthread/60745/

It works pretty well.  I don't know that it could pass an EPA test, but it's much better than before regarding burn times and chimney smoke.  And it gets HOT, I routinely see stovetop temps of 700 - 800 F for a period of time after I engage the secondary air and shut down the primary.  I only use this stove when it gets way below zero degrees to keep the cellar warm.  The Quadrafire baffle material looks brand new, not even the slightest discoloration or soot.  Pretty amazing stuff.


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## comstock1869

I have a neighbor who warped and burned a hole in the side of a Fisher insert stove converted as a free standing stove (home made legs and all).  This is a one match per season stove running 24/7 for 7 months of the year warming his 2 story shop building attached to his office.  Keeps the place in the 60s.  They pack it full of birch.  They welded up some battleship plate and it is back in business.  This all done with out a baffle and burning gobs of wood. 

Has anyone who has added this baffle figured out their wood savings?  Are we talking 25% savings? More? Less?  Just looking for an update before it gets cold.  I have read this thread and it sounds good for my Fisher Grandpa Bear.


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## WES999

TX-L said:
			
		

> Here is what I did last year:  https://www.hearth.com/econtent/index.php/forums/viewthread/60745/
> 
> It works pretty well.  I don't know that it could pass an EPA test, but it's much better than before regarding burn times and chimney smoke.  And it gets HOT, I routinely see stovetop temps of 700 - 800 F for a period of time after I engage the secondary air and shut down the primary.  I only use this stove when it gets way below zero degrees to keep the cellar warm.  The Quadrafire baffle material looks brand new, not even the slightest discoloration or soot.  Pretty amazing stuff.



Nice job on the baffle addition, looks great. My Fisher also has a baffle and secondary air mod.
I also added a viewing window so I could see the fire. I used a 3" X 3" piece of ceramic glass purchased form McMaster Carr. Here are some pics.


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## Redbear86

thats cool, i was kinda wondering the same thing that comstock was asking did you add the baffle and run it for a while so see how much you've gained with the air tubes? When i saw the whole you cut on the door of that fisher i had to shake my head....


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