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Post by satamax on May 6, 2014 22:55:01 GMT -8
Hi everybody.
Well, i'm at my fourth batch box, all iterations included. Some of you start to have made a bit of thoses too.
The thing is, i find them a bit temperamental. Put one stick too much, or the wrong way in the box, and they start smoking. Not smoking back! I haven't spoken about when you stick a piece of wood in the port accidentaly.
Any idea why they behave like this. Even guesses could help.
May be too much wood slows the air flow. Hence starving the stove? Any other ideas? I would say, this happens even if i haven't filled the box to the top.
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Post by mintcake on May 7, 2014 8:15:29 GMT -8
I've seen it too. My guess: too much hot wood surface area => too many hydrocarbons for the oxygen supply => incomplete burning.
I remember reading that Peter doesn't ever use "lots of small stuff" (or a similar phrase) in his stove. Quite what that means, I don't know.
The problem is once this starts then you you can solve the problem temporarily with more
front air (open the door), and then you get more wood burning hotter....
Maybe the solution is better draught ("suck") from the chimney... I know I didn't have it happening nearly as much before I closed the bell on my test stove.
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Post by smarty on May 7, 2014 10:09:03 GMT -8
I seem to remember that Peter said something about using larger chunks of wood when re-fueling to stop the thing suffocating itself in combustion gasses from the superheated burning environment.
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on May 7, 2014 13:37:39 GMT -8
I've been doing just that recently when the stove has been hot, using some very dry round logs between 3" and 5" diameter and about 6" long. After placing these on the ash bed they take a minute or so to ignite. The stove then burns ridiculously hot - I had the rear of the burn chamber and riser turning orange. Opening the door you can't hold your hand closer than 18" and the burn chamber is completely white - no soot anywhere.
I've just processed 6 tons of firewood into 1" x 2" x 12" chunks. I still have 4 tons to do so I won't make these chunks so thin. |
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Post by satamax on May 7, 2014 22:05:18 GMT -8
Ok then, bigger pieces of wood. I'll remember this. Well, having the back of the firebox orange is pretty common for me on the green machine. The P channel metal is starting spalling.
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Post by DCish on May 8, 2014 7:25:19 GMT -8
I'm fond of the "use a larger piece of wood" idea -- firebox temp is regulated and burn time extended with minimal intervention. However, the curious tinkerer in me wonders... if hydrocarbon overload is the problem, would a larger p channel (throttled to standard flow during normal operation) allow enough secondary air in to complete combustion under peak fuel conditions? Of course that presumes that the system can handle the additional heat that is created.
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Post by grizbach on May 8, 2014 8:44:46 GMT -8
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Post by grizbach on May 8, 2014 8:48:04 GMT -8
Bottom line is:
Without enough draft and the CFM's of oxygen that go along with it, There is a limit to how much fuel you can put in a system.
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