Adding secondary burn to this unique stove

[Blazzinghot]

Looks like bholler already stated what I was thinking when I read this last night. You showing the pictures of your stove will give others ideas on adding secondary burners. I am sure that AtomicDog is busy working on his wood stove so hopefully will give an update on the results when he is finished.

 

[snobuilder]

One new addition is this plenum to hold the heat around the secondary manifold in an attempt to pre-heat the incoming secondary air to higher temps.

 

[Blazzinghot]

snobuilder, that is a well built box you put around your secondary air intake tubes. I am sure it will help along with the ceramic board with the secondary tubes insides the wood stove. I hope this will make the secondary burn improve. But is you already are getting clean smoke it sounds like something is working right.

 

[AtomicDog]

Sorry. Still following. We've hit a cold snap so I'm holding off on hacking up my stove. Thanks for the additional information snobuilder. I'm still trying to wrap my head around all of the variables involved. Air temp, baffle, number of holes, draft, type of steel, thickness, flue location, insulation, secondary chamber size......... I miss the old days when you just opened the door and tossed in something that looked like it might burn. The biggest hazard was a nail in your tire from where you dumped the ashes. The door knobs and hinges are easy to spot.

 

[Blazzinghot]

AtomicDog, Thanks for getting back with us. I sometimes feel the same way you do about the good old days of just tossing in a log and closing the door. While you are waiting for a warm day to work on you stove take some time to read about secondary burners and sometimes you can find different diagrams on the internet on how they work.

Almost every time I sell a wood stove with secondary burners the person buying the wood stove does not have a clue about secondary burners. I try to explain to them how it their new wood stoves work. Sometimes they give me a blank stare as it is totally new to them. So you are not alone. When I first joined this forum I did not have clue myself. But it is not really that complicated once you understand the main principles. But there is always a learning curve when we learn new things.

 

[AtomicDog]

So if I understand this correctly:

• I need to create a secondary chamber by installing a baffle
• This chamber will consist of the burner pipes and new flue opening
• There needs to be a path for combustible gasses to flow from the fuel chamber to the secondary combustion chamber
• The baffle needs to be removable for cleaning

I think I understand the process. What I'm trying to determine is what affect different variables in the design have on the function, such as the size of the upper chamber, placement of insulation, etc.. I do tend to over complicate things.....

 

[bholler]

So if I understand this correctly:

• I need to create a secondary chamber by installing a baffle
• This chamber will consist of the burner pipes and new flue opening
• There needs to be a path for combustible gasses to flow from the fuel chamber to the secondary combustion chamber
• The baffle needs to be removable for cleaning

I think I understand the process. What I'm trying to determine is what affect different variables in the design have on the function, such as the size of the upper chamber, placement of insulation, etc.. I do tend to over complicate things.....

You are not creating a secondary combustion chamber. You are simply adding a baffle which will increase firebox temps and extend the smoke path. The secondary air tubes go under the baffle and inject fresh air into the firebox above the fuel.

 

[Blazzinghot]

AtomicDog, As stated you are making a baffle over the top of your burn tubes to reflect more heat on them. The top side of the chamber is for the fire to escape out through the flue. The insulation goes on top of the baffle (or what every you decide to use) is to increase heat temps on the bottom side of the baffle in the location of the heat tubes. The air coming out of the heat tubes mixes in the lower part of the stove and creates the secondary burn there then it swirls around the end of the baffle to the topside out the flue. Take a look at this post https://www.hearth.com/talk/threads/diy-secondary-combustion-air.178840/ This will give you a reference point of how this works.

 

[snobuilder]

So just a quick update on my DAKA add on wood furnace . My initial secondary air supply as pictured in post 52 doesn't get hot enough for a good tertiary burn off although it WAS burning cleaner at times. My latest set up made of 1x2 tube steel and reuse of slotted 1/2 " blk. pipe sits inside the stove similar to the set up in my pleasant hearth stove.
The box tubing as in pic 52 now supplies air as well as 2 new 1x2" intakes cut in at the bottom front of stove. First fire last night showed a better secondary burn off yet smokey when large splits were added. Today I used resplit large wood and it runs pretty much smoke free.
I have a make shift baffle set up that will be improved when I get my insulated panel. I also will be raising the floor/grate to make a smaller height box. 20+" now.

 

[Blazzinghot]

snobuilder, Looks like you are on your way to improving you wood stove. The flame on the lighter is pulling in good secondary air at the intake. No smoke coming out the chimney is certainly a good sign something is working right. You will get smoke sometimes depending on the inside temp of the stove. The secondary on my homemade shop stove works with no smoke only when the top of the stove gets about 400 degrees. It was not my best build. Do you have a wood stove thermostat to check the outside temp of the wood stove? I am anxious to see what happens when you get your insulated panel.

 

[snobuilder]

snobuilder, Looks like you are on your way to improving you wood stove. The flame on the lighter is pulling in good secondary air at the intake. No smoke coming out the chimney is certainly a good sign something is working right. You will get smoke sometimes depending on the inside temp of the stove. The secondary on my homemade shop stove works with no smoke only when the top of the stove gets about 400 degrees. It was not my best build. Do you have a wood stove thermostat to check the outside temp of the wood stove? I am anxious to see what happens when you get your insulated panel.

I scan the stove in various hot spots and am running 350 to 550. External single wall pipe temp is just into the burn zone.

Raised the grate 4" to shrink the space between load and tubes. With the half splits it lights and burns clean almost instantly.
I'm not seeing a gas grill type of secondary burn but the chimney shows clean and hot.
I will be putting slide dampers on the 2 new secd. air intakes as I think the wood is burning a bit fast even though the primary air intake is set lower than normal.

 

[bholler]

I scan the stove in various hot spots and am running 350 to 550. External single wall pipe temp is just into the burn zone.

Raised the grate 4" to shrink the space between load and tubes. With the half splits it lights and burns clean almost instantly.
I'm not seeing a gas grill type of secondary burn but the chimney shows clean and hot.
I will be putting slide dampers on the 2 new secd. air intakes as I think the wood is burning a bit fast even though the primary air intake is set lower than normal.

Does this stove have a glass door?

 

[Blazzinghot]

bholler, I don't think this DAKA has a window. This is a long thread but it seems like this was discussed. But snobuilder can correct me if I am wrong.

snobuilder, it would be hard for you to see the secondary burn because when you open the door to see the fire the air then is drawn in through the door opening and the secondary air draft weakens. There is also allot of discussion over what a secondary burn looks like. You don't always get that nice propane type flame you see on a burner. It depends on the draft and how much primary air is coming into the stove. Sometimes I get nice blue flames that dance in mid air in front of the glass which is a good sign of a good secondary burn. But then it also depends on the type of wood being used. I am sure you have read some of the posts on secondary burns and what they look like.

 

[snobuilder]

No window, I sneak a peak with the door cracked but that is still a lot of air intake . Overall It is burning good and hot on less primary intake air but also burning as fast as before the secondary system. I do believe it is putting out more heat though. Temps are back down in this area so today will tell as more of a fair comparo. So far It is worth the effort . This stove was a "smoke dragon" before. Mostly due to operating it in the "creosote temp" range to get a long burn out of it. Even If I go through the same amount of wood, it's a win. Time will tell.

 

[bholler]

No window, I sneak a peak with the door cracked but that is still a lot of air intake . Overall It is burning good and hot on less primary intake air but also burning as fast as before the secondary system. I do believe it is putting out more heat though. Temps are back down in this area so today will tell as more of a fair comparo. So far It is worth the effort . This stove was a "smoke dragon" before. Mostly due to operating it in the "creosote temp" range to get a long burn out of it. Even If I go through the same amount of wood, it's a win. Time will tell.

Opening the door at all will instantly kill the secondary combustion. Adding secondary combustion also won't change your burn times at all on its own just give you more complete combustion. It may or may not give you more heat out of each piece of wood

 

[snobuilder]

New update. I added a 6x6 glass panel to the door last night and also now have a better baffle in place above the 4 burn tubes.
So I was able to view my burn for the first time. What I saw was impressive and even had the " gas grill" effect at times.
Unfortunately without an air wash the glass sooted up after 40 minutes or so.
I also lowered the grate back down from 4" to 2" above factory level. Next I will try to achieve a longer burn time.

 

[Blazzinghot]

snobuilder, I noticed on one of the other posts you stated you ordered a glass window for your wood stove. I know the feeling when you are able to see the fire and watch the secondary burn in action. I had a stove I made from wheel rims with a secondary burner and the only way I could seen inside was from a hole in one of the rims from the tire stim I forget to weld shut. Ha I could not see much so just put a bolt in the hole.

I was wondering how the window was going to work without a air wash system but sometimes is you wait and as the fire gets hotter the soot will burn off the glass. The secondary burn can vary depending on the draft and wood. Most of the time I get nice dancing yellow mixed with blue flames which I enjoy watching. Sounds like you have drastically improved your wood stove.

 

[snobuilder]

snobuilder, I noticed on one of the other posts you stated you ordered a glass window for your wood stove. I know the feeling when you are able to see the fire and watch the secondary burn in action. I had a stove I made from wheel rims with a secondary burner and the only way I could seen inside was from a hole in one of the rims from the tire stim I forget to weld shut. Ha I could not see much so just put a bolt in the hole.

I was wondering how the window was going to work without a air wash system but sometimes is you wait and as the fire gets hotter the soot will burn off the glass. The secondary burn can vary depending on the draft and wood. Most of the time I get nice dancing yellow mixed with blue flames which I enjoy watching. Sounds like you have drastically improved your wood stove.

This unit is in the basement so it isn't a center piece for fire viewing. I have an excellent glass cleaner that will clean it up during cool downs and restarts.

 

[MR. GLO]

This unit is in the basement so it isn't a center piece for fire viewing. I have an excellent glass cleaner that will clean it up during cool downs and restarts.

Check the smoke at first burn of the day. My old stove burned no smoke but the first burn was a bunch of gray smoke each day for 10 min or so.

Let us know if you see any longer burn times.

 

[clancey]

What kind of glass cleaner are you using snobuilder for I have read that one needs to be very careful with the choice because something like windex I think would scratch the stove glass and make permanent damage--do not know if this is true buts that what I heard...clancey

 

[snobuilder]

What kind of glass cleaner are you using snobuilder for I have read that one needs to be very careful with the choice because something like windex I think would scratch the stove glass and make permanent damage--do not know if this is true buts that what I heard...clancey

Meeco Brand

I found I can use a razor blade scraper when it isn't cool enough to use cleaner.

 

[bholler]

What kind of glass cleaner are you using snobuilder for I have read that one needs to be very careful with the choice because something like windex I think would scratch the stove glass and make permanent damage--do not know if this is true buts that what I heard...clancey

Windex is fine but won't do much to clean creosote. Honestly I use a torch lots of times to start if the glass is bad.

 

[clancey]

Why not use the wood ash because that cleans it real well...clancey

 

[bholler]

Why not use the wood ash because that cleans it real well...clancey

Wood ash does work very well for light buildup

 

[snobuilder]

Window to my hearth....LOL