Secondaries and too dry a wood?

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oldspark

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OK I am new to the EPA stove thing but I have read a lot ( :lol: ) and this time of year with the small fires I am not getting much of the secondary action, however I put in a piece of Oak that part of it was past its prime and the secondaries kicked in immediately and burnt for a little while and then backed off. I assume this is normal with wood that is past its prime correct?
 
Volume of the wood is going to play a part in it as well, but the better quality as well.
 
smokinjay said:
Volume of the wood is going to play a part in it as well, but the better quality as well.
So the too dry firewood gives off gases right away and kicks in the secondaries I guess, I think I read about that on this site but was the first time I observed it.
 
oldspark said:
smokinjay said:
Volume of the wood is going to play a part in it as well, but the better quality as well.
So the too dry firewood gives off gases right away and kicks in the secondaries I guess, I think I read about that on this site but was the first time I observed it.

"too dry" - there is a term that is difficult to define. I believe that most folks tend to agree that naturally dried wood can't get 'too dry' in most cases. The exceptions being those who live in very dry desert regions where relative humidity stays in the single digits most of the year and/or if you store your wood in an old barn/greenhouse or some other structure that is situated such that it acts like a kiln for a long time.

Other than that you would need to kiln-dry your wood to get it "too dry".

Those secondaries are what you are supposed to see :)
 
Slow1 said:
oldspark said:
smokinjay said:
Volume of the wood is going to play a part in it as well, but the better quality as well.
So the too dry firewood gives off gases right away and kicks in the secondaries I guess, I think I read about that on this site but was the first time I observed it.

"too dry" - there is a term that is difficult to define. I believe that most folks tend to agree that naturally dried wood can't get 'too dry' in most cases. The exceptions being those who live in very dry desert regions where relative humidity stays in the single digits most of the year and/or if you store your wood in an old barn/greenhouse or some other structure that is situated such that it acts like a kiln for a long time.

Other than that you would need to kiln-dry your wood to get it "too dry".

Those secondaries are what you are supposed to see :)
Let me explain better, the temp on the stove top was too low for the secondaries to kick in (less than 400) but the second I put the piece of wood in they lit up for a couple of minutes and died off, the wood was punky on one end so I know it was that piece of wood. Maybe too dry was the wrong term and I should have said punky.
 
oldspark said:
Let me explain better, the temp on the stove top was too low for the secondaries to kick in (less than 400) but the second I put the piece of wood in they lit up for a couple of minutes and died off, the wood was punky on one end so I know it was that piece of wood. Maybe too dry was the wrong term and I should have said punky.

I thought that was what you meant when you said "part of it was past its prime", but thanks for clarifying. Makes sense to me. I'll bet it's lots drier as well.

In punky wood, the wood mass that has disappeared from the split through fungal action gets replaced by air spaces. That allows the internal water to be released faster, so the wood will get very dry if kept away from rain and snow. I've had wet, punky cherry sapwood turn into powder in my stove room in a couple of days (not a good thing to breathe BTW). Extra dry wood filled with more air spaces makes for very quick burning, which means is produces more smoke in the beginning, and as you know, that is what fuels your secondaries.

I'd imagine you'd get more controlled burns with punky wood if you mixed in some semi-seasoned or large dry splits into the box, but as long as your secondary combustion or cat combuster can keep up with the excessive smoke production, you shouldn't have any problems.
 
Keep in mind that the stove top temp of 400 is not what determines whether or not you have secondary combustion. The internal temperature in the firebox will control this. For non-catalytic stoves, I believe you're looking for an internal temp of around 1,100F or so to get into prime secondary combustion.
 
Pagey said:
Keep in mind that the stove top temp of 400 is not what determines whether or not you have secondary combustion. The internal temperature in the firebox will control this. For non-catalytic stoves, I believe you're looking for an internal temp of around 1,100F or so to get into prime secondary combustion.
Just using that as a reference point as I have not seen any secondaries under that temp to speak of.
 
oldspark said:
Pagey said:
Keep in mind that the stove top temp of 400 is not what determines whether or not you have secondary combustion. The internal temperature in the firebox will control this. For non-catalytic stoves, I believe you're looking for an internal temp of around 1,100F or so to get into prime secondary combustion.
Just using that as a reference point as I have not seen any secondaries under that temp to speak of.

Understood. ;-)
 
oldspark said:
OK I am new to the EPA stove thing but I have read a lot ( :lol: ) and this time of year with the small fires I am not getting much of the secondary action, however I put in a piece of Oak that part of it was past its prime and the secondaries kicked in immediately and burnt for a little while and then backed off. I assume this is normal with wood that is past its prime correct?

+1

I get that when I burn just pallet wood. Secondaries kick off with the stove top temp under 200.
 
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