Author Topic: Wood Moisture content  (Read 3159 times)

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Offline JoJoDapyro

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Wood Moisture content
« on: August 09, 2014, 11:41:29 pm »
Has anyone else had issues with "Seasoned" wood twisting when getting it to a dryer climate than where it came from?

I have only obtained wood from out of state one time, and of the 4 staves, 3 twisted. Strangely, it took about a month for it t happen, and it has even been more humid here than most summers. If this is normal, how do you keep it from happening?
If you always do what you always did you'll always get what you always got.
27 inch draw, right handed. Bow building and Knapping.

Offline J05H

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Re: Wood Moisture content
« Reply #1 on: August 09, 2014, 11:55:42 pm »
IMHO it's probably normal. When wood comes to your area from a more humid part of the country, even if its reached equilibrium moisture content and been there for years, its going to have to dry out quite a bit to re-normalize to your RH levels. And any time wood dries, there is the possibility for problems.

I'd say you could combat warpage by strapping your staves to a 2x4 or something when you receive them, and if possible keep them in a slightly more humid place for a while to kind of slow down the process.
If you never have time to do it right, you'll always have time to do it over.

Offline Pat B

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Re: Wood Moisture content
« Reply #2 on: August 10, 2014, 12:10:41 am »
Wood will find equilibrium as far as moisture goes so if it travels from dry to wet or vice versa it needs time to equalize. Even from one season to another can cause these problems.  Taking a stave down to near bow size and strapping it to a form to season can help with this or just use a heat gun later to make adjustments.  ;)
 Where the wood comes off the tree can cause these problems too. If the stave is reaction wood no telling what it will do.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline mwosborn

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Re: Wood Moisture content
« Reply #3 on: August 10, 2014, 01:15:14 am »
Hey Pat - can you elaborate on "reaction wood"?  I have never heard this term before.  Would it be sapwood?  The wood nearest the cambium? Thanks.
Enjoy the hunt!  Mitch

Offline CustomArcher15

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Re: Wood Moisture content
« Reply #4 on: August 10, 2014, 01:26:43 am »
Reaction wood is like a tree that was leaning. The compressed and stretched areas wood be considered reaction wood to as far as my knowledge goes. When you split the tree the deflexed part of the tree will reflex and the reflexed half will deflex because the cells were stretched/smashed and are returning back to regular size.

Offline JoJoDapyro

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Re: Wood Moisture content
« Reply #5 on: August 10, 2014, 01:59:18 am »
OK, To go a step further. Is there reason to use steam in a more dry area vs. just a heat gun? It is super dry here. The Osage I am currently working on has twist in the end of one of the limbs. Do you think I am better off using a concentrated steam method (wet cloth and heat gun) than just dry heat? My house also has central air, so it is even dryer inside than out. I'll put a humidifier in my attic when I get it set up as my shop. I am also looking to get a hotplate and make a little portable steamer in the future.
If you always do what you always did you'll always get what you always got.
27 inch draw, right handed. Bow building and Knapping.

Offline Eric Krewson

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Re: Wood Moisture content
« Reply #6 on: August 10, 2014, 09:54:08 am »
Think of a bent tree like a bow, the belly will deflex(compression wood) when cut free, the back will reflex(tension wood) and the sides will dogleg(reaction wood).

Offline bradsmith2010

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Re: Wood Moisture content
« Reply #7 on: August 10, 2014, 12:26:04 pm »
roughing it out and clamping it in place,,, or clamp the whole stave as suggested,, and I would say its  normal depending on the humidity it comes from,, and the humidity its going to,,,

Offline Pat B

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Re: Wood Moisture content
« Reply #8 on: August 10, 2014, 12:49:49 pm »
The rule of thumb for heat correcting bows is dry heat for dry wood and wet heat(steam, boil) for wet wood but there are always exceptions.
 Osage manipulates very well with dry heat however if you are going to make radical bends like recurves you might be better with steam or boiling. I think I'd seal the area to be steamed with shellac if the wood is dry to prevent checking.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline E. Jensen

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Re: Wood Moisture content
« Reply #9 on: August 10, 2014, 05:19:47 pm »
Just add on to what already been said about compression wood, yes its wood that a tree forms to correct itself if leaning.  Softwoods form compression wood only, on the underside.  Hardwoods form tensionwood only, on the top. 

I got myself a compression pine sapling.  Only problem is I wasn't sure if the compressionwood is supposed to be the back or the belly.  I figured the belly.  But that also means that my bow is now super duper reflexed.  Not something I want on pine.  I roughed it out and clamped it flat so hopefully it stays straight when dry.

Offline George Tsoukalas

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Re: Wood Moisture content
« Reply #10 on: August 10, 2014, 07:12:22 pm »
Pine makes good arrows. Not so good for bows.
Seasoned wood may not be dry enough to be a bow.
Jawge
Set Happens!
If you ain't breakin' you ain't makin!

Offline E. Jensen

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Re: Wood Moisture content
« Reply #11 on: August 10, 2014, 07:38:45 pm »
Nope.  But we'll see what we can do with it