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Log Diameter Max

Post in 'The Wood Shed' started by MeLikeUmFire, Oct 11, 2009.

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  1. MeLikeUmFire

    MeLikeUmFire Member

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    Hey guys what is your opinions on the max log diameter i should be putting into my insert? I have a insert that will take 18" wood. I know i prob. want some of the logs for overnite burns, but what is too big a diameter to be efficient?

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  2. burntime

    burntime New Member

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    I split it all smaller and just pack it full if I want an overnight burn. Thicker takes longer to dry...
  3. CowboyAndy

    CowboyAndy New Member

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    bigger doesnt always take longer to dry... if you take 2 logs that are both the same length, but one smaller diameter and one larger, the larger will actually dry faster. im talking with the bark on. reason is that there is more surface area exposed with the larger log, therefore more area for moisture to escape. i left many maple logs whole last summer and realized last winter they were not ready to burn. this year they will be, but some of the smaller branches STILL arent.


    i would say 6" is okay to leave whole as long as they have plenty of time to season. if not then split them as small as you can.
  4. Bspring

    Bspring Feeling the Heat

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    I have a Big Jack furnace and they told me around 8 inches would be good.
  5. burntime

    burntime New Member

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    Andy, I gotta disagree with you on that one. In the same species the larger will ALWAYS take longer to dry.
  6. Backwoods Savage

    Backwoods Savage Minister of Fire

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    It mostly depends upon the stove as to how big of a log you should put in.

    I also agree with burntime on the drying.
  7. CowboyAndy

    CowboyAndy New Member

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    backwoods and burntime, im saying that from personal experience. last summer, we cut a giant sugar maple. most of it was split (rather large at that) in july. the splits were burnable by feb (marginal, but usable). the 6-8" rounds were as well. the 2" branches were trash... they hissed and bubbled more than the splits and larger rounds.

    they were all stacked in the same place, same amount of sun and wind...
  8. burntime

    burntime New Member

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    You opened it up when you split it. The bark on the smaller pieces kept the moisture sealed. Thats your difference...
  9. CowboyAndy

    CowboyAndy New Member

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    agreed. but there was a distinct difference between the ROUNDS... after the same period of time the larger diameter ones seemed more dry and burn better than the smaller diameter ones.


    reason is that there is more surface area on the larger diameter ones for the moisture to escape.
  10. burntime

    burntime New Member

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    Yes, rounds dry slower... Thats because the bark seals it in. You are 100% correct, more surface area dries faster...
  11. CowboyAndy

    CowboyAndy New Member

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    but a few posts ago you disagreed that smaller rounds dry slower than larger ones...

  12. Backwoods Savage

    Backwoods Savage Minister of Fire

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    More surface area dries faster? That is true when speaking of splitting wood. In the round, that more surface area is still basically the same because there is more wood in a larger round than a smaller round. Sorry, I don't buy it and it has been my experience that a larger or smaller round will dry out in about the same length of time. Now if one would dry faster than the other, I'd bet on the small one drying faster.
  13. burntime

    burntime New Member

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    Andy, you are talking rounds and splits. Big difference. 2 splits in same species...larger takes longer to dry. 2 rounds, bark seal it in, larger is longer to dry. Does that make sense?
  14. CowboyAndy

    CowboyAndy New Member

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    i totally see what you guys are saying. im not comparing splits to rounds, im comparing rounds to rounds. and im just saying that in MY experience, the the larger ROUNDS seem to be drier than smaller branches.
  15. Bspring

    Bspring Feeling the Heat

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    The big rounds may have more surface area than the smaller ones but I don't think they would as a percentage of the diameter. There may have been another factor such as when some trees die the top dies first and the lower branches may hang on for another year.
  16. Tony H

    Tony H New Member

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    This debate could go on and on. Why, because of conditions beyond our control like bspring mentioned tree dying and how about just the position on the tree. We normally see the lower parts of the tree contain more moisture so unless we log the wood and starting moisture one of the rounds might be dryer from the start.
    Splits it makes a difference on the shape of the split a wide pie shaped split will have more surface area then a square cut split so even though both start off the same one will be little dryer a little earlier. Other factors could include the place on the stack of wood and the sun and wind exposure from the north vs the south side plus how packed in the wood is and the differing air flow.
    I suggest we present this dilemma to the folks at Mythbusterrs and let them do some extensive testing to find ways for us to dry wood better and faster.
    .
    .
  17. gzecc

    gzecc Minister of Fire

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    Its funny. I pick up some splits and think, man what was I thinking when I split this. Its so friggin big.
    I don't know if I get tired while splitting or if my perception of "big" changes.
  18. shawng111

    shawng111 Member

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    I usually give it a split if anything over 5-6 inches
  19. PunKid8888

    PunKid8888 New Member

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    if I can't grab it with one hand on the end then I split it again. Last year I split a bunch of smaller rounds because I figure one split would help it season, which it did. But now I have a bunch of kindling that would have been better as rounds for overnight burns. once I get my wood supply a few season ahead I will leave everything bigger.
  20. gzecc

    gzecc Minister of Fire

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    I loosly use that "hold it in one hand from the end" technigue, but then I wonder how long I should be able to hold it. Everything is so complicated. An ash split that I can hold is nothing compared in weight, to a black locust or oak split.
  21. Danno77

    Danno77 Minister of Fire

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    I like this method. It's probably necessary for those who need to hold with one hand while they load it into the stove. For my fireplace I never worried about it. since everything sits lateral to the opening with plenty of room on the sides you could hold both ends and toss it in. with a stove, even one that loads from the front in an E-W manner, there isn't enough room to get both hands on the ends to put it into the stove.

    Only problem is that wet wood weighs a lot more than dry wood, so maybe I'll make my splits just a little too heavy to hold, because when they dry out they'll be manageable.

    Thanks for this tip, I'll try it out when I start splitting in a few weeks.
  22. afblue

    afblue Feeling the Heat

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    Rounds to Rounds the larger full round will dry faster because the ratio of bark on the outside to the cross sectional area of the log.

    6"x18" round
    Bark surface area=(pi)DxL= 3.14X6X18= 339.12Sq in
    End surface area=2(pi)r^2= 2x3.14x3^2=56.52x2 sides= 113.04 sq in
    3:1 bark to cut end ratio

    12"x18" round
    Bark=3.14x12x18=678.24 sq in
    ends=2x3.14x6^2x2=452.16 sq in
    1.5:1 bark to cut end ratio.

    24x18" round
    bark 1356.48 sq in
    ends 1808.64
    .75:1 bark to cut end ratio

    Therefore a cut round: 2X the diameter has 2x the cut end surface area. Its not magic, its math.

    Spliting any log will increase the surface area and decrease drying time.
  23. crazy_dan

    crazy_dan New Member

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    I use the wedge on my splitter if it is bigger than the height of it squared seams to work out fine for me makes it where I can put 4 wide and 2 high in my summit.
  24. Danno77

    Danno77 Minister of Fire

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    A 6x18 log has a volume of 508cubic inches
    a 12x18 log has v=2034ci
    a 24x18 log has v=8138ci

    so a cut end to volume ratio is:
    6"log = 113sqin to dry out 508cuinches of wood
    12" log =452in^2 to dry out 2034ci
    24" log =1808in^2 to dry out 8138ci

    if you do the math on that you see that because the end size is in direct proportion to the volume they should all dry out equally fast when in the round IF THE DRYING ONLY OCCURS THROUGH THE END.

    if you do the math on total exterior surface area on a round then you'll find the following
    6" = 452 surface sqin for 508ci
    12" = 1130sqin for 2034ci
    24" = 3164sqin for 8138ci

    SO, to summarize this information. You are claiming that because a water tower has an 8ft diameter pipe on it that it will surely drain all the water from it faster than garden hose can drain water from a coffee can. I mean an 8ft pipe is wayyy bigger, right? I believe my calculations show that all rounds will dry at an equal rate, but only when drying occurs ONLY through the ends of the round, this is because the volume of water is much greater in a larger round, therefore it takes more surface area to expel said water.

    HOWEVER, since drying occurs through all exposed surfaces (although the absence of bark is preferred for drying, i suppose) the previous calculations are a bare minimum of drying relationships. Given equal ability for water to dry through all surfaces of a round, the data above suggests that a smaller round will dry MUCH faster than a larger round. I'd call this an optimistic maximum or drying relationships. the real truth likely lies in between, but I can assure you that it is not due to any surface area mathematics that larger rounds dry faster. If that's the case, then it's likely due to how smaller rounds fit together and how surface to surface contact with other rounds inhibits drying, or some mumbo jumbo stuff like that.
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