Sunday, February 6, 2022

975 Fahrenheit Hot Transformation of the Two Dog Camp Stove into a clean burning efficient wood stove via ceramic fiber board and fire bricks and heat exchangers

 The Two Dog stove - I think I got the last one made? - they are locally made and a great wood stove. It worked as advertised. Once I got it up to temperature it burned clean but it cooled down fast and would not burn completely - with chunks of wood left over. The clean Burn is the BEST part - there is nothing worse than that nasty smell of wood smoke. I had NONE of that smell from the chimney when I went outside. Very wonderful.

NOW I get a clean burn down to ash and lots of blue flame. The blue flame does not come out in the photos - not sure why - it just kind of looks off color. 

Let's start with the photos.

PROOF! Good thing this temperature reader goes up to just over 1000 F.

So I got this reading many times - in the 980s - the problem was I was FREEZING in the Hermit Hut!!

Why? Because I put all of the Rutland dense fire bricks that are rated up to 2700 Fahrenheit. So I took out two of those bricks that were on the walls - towards the front door of the stove. Each brick was about 450 F. so it had just kept absorbing and absorbing heat from the fire. So NOW I just had the four fire bricks on the "floor" of the wood stove and suddenly the flue collar temp jumped up at least 150  F. degrees and at best over 650 F. 

So that means the clean exhaust was not condensing again as before I had flue exhaust temp at around 200 F. - way too cold. So it would leave the chimney as a big puff cloud of steam. It was a CLEAN  burn with no wood smell at all. Very wild.

NOW the exhaust was not even any water vapor - just steam shivering - and also I was kicking out enough heat back into the Hermit Hut to warm it up finally. In fact if I had the wood stove door open then it was too hot to hold anything in front of the stove for more than a minute!! I had to keep back at least two feet.


 The flames even had a "double horn" from the secondary air tube that went up the back wall. This "double horn" flame is key to getting a clean burn - as per the Peter "Batch Box" mass heater design. I would get a "rocket sound" as I the stove pipe extend straight up before going off at a 30 degree angle.

So the exhaust slows down at the 30 degree angle as well.

Here it is - notice on the left how the flames curl under as two horns in the opposite direction - that is the classic "Double Horn" burn of the Batch Box heater due to the secondary air pipe going up against a "baffle" just before the "heat riser."

So this is obviously some wild fire but it was too hot to watch with the fire stove door open!!

So then I heated up four gallons of water to hold the heat - so when the fire goes out the LAST thing to cool down in the water. And it is plenty cold outside - we have below zero Fahrenheit - which is more than thirty degrees below freezing Fahrenheit - so I drove the car every six hours to make sure the battery stayed charged up.


Those are the aluminum heat exchanger strips and then some stainless steel chain that mainly was just piled up the stove just around the collar flue leaving the stove. So those "heat exchangers" dropped the stove pipe temperature about 300 degrees Fahrenheit right from leaving the stove.


Meanwhile outside the Hermit Hut is buried in snow. I cleared it off - first thing - before taking down my roof support post.

So a couple feet of snow. I would knock into it to break up the hard stuff attached to the roof.

OK so now it's time to fire up the wood stove - it was getting very cold. So I didn't have time for precise measurements. I did use a tape measure.


The high flame on the left is from the secondary air pipe sticking up and literally the air coming out was just burning like a natural gas or propane flame!! Good thing I got stainless steel pipe since it was in 980 Fahrenheit. But the steel baffle was heavily oxidized and probably won't last long. So I will have to make a full ceramic fiber baffle at that point. I have enough left over ceramic fiber board to do so.

So in the back of this "after burn" chamber I have the pumice highly insulation fire brick on the floor on top of ceramic fiber board. That pumice fire brick does not absorb heat since it is an "insulation" fire brick. So it protects the ceramic fiber from the logs. So I have four sides of just ceramic fiber board - as the "after burn" chamber with the secondary air pipe that is preheated along the bottom of the wood stove

This is looking down from above the front door - so you can see the secondary air pipe that is 1/2 inch pipe as stainless steel - and it is opening up to the primary air opening on the wood stove door. So then the pipe runs along the base as I showed in previous videos.


That's how the 30 degree stove pipe goes off into the side wall while the 4 gallon water pot sits on top of the wood stove. 

Here I have boots warming on a drying rack I set up in the front of the wood stove - and gloves warming up above. I also dried the socks - you could see the water steam as they all dried off. One thing about winter is the boots and socks get wet and it's dangerous in the cold. The floor of the hut is the cold ground!! So it was still 30 degrees around the end of the hut inside along the floor. Also there's a lot of air opening in the hut although the walls are "insulated." They have lots of circulation.

Without a wood stove then it's difficult to dry off the wet winter clothing!! So in a way a wood stove is superior heat. With this set up then I get a clean burn without all the pollution plus MORE heat from the wood stove!! The heat gets absorbed into the Hermit Hut since the walls have a lot of clay as "clay slip" insulation.

Did I need my sleeping bag at night - oh yeah - there was still below freezing along the walls near the floor - and I definitely needed my "antarctica" sleeping bag that I use. But then once I got the wood stove going again the Hermit Hut warmed up fast. Even though I made a small fire this morning I still got the same 975 degree Fahrenheit "after burn" secondary air combustor temperature!

Previous blog posts on this Wood Stove modification research:

https://elixirfield.blogspot.com/2022/02/two-dog-wood-stove-mod-rutland-fire.html

https://elixirfield.blogspot.com/2022/01/the-two-kinds-of-fire-bricks-available.html

https://elixirfield.blogspot.com/2022/01/century-stove-double-m-innovations.html

https://elixirfield.blogspot.com/2022/01/wood-stove-modification-stainless-steel.html

https://elixirfield.blogspot.com/2022/01/wood-stove-mod-update-gardus-sooteater.html

https://elixirfield.blogspot.com/2022/01/woodstove-mod-part-7-two-ceramic-fiber.html

https://elixirfield.blogspot.com/2022/01/part-6-woodstove-modification-12-inch.html

 https://elixirfield.blogspot.com/2022/01/part-5-inside-skinny-on-century-stove.html


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