Replies

1. 
   saschafer | Dec 06, 2007 04:40am | #1

   When you say "inside there are occasional cracks," do you mean that if you cut a piece out of the board that you can see cracks on the end grain surfaces? If so, these internal cracks are called "honeycombing," and there is nothing you can do to repair the wood. You can only use the sound wood between the cracks.

   Honeycombing is caused by drying wood until it is very dry, and then adding moisture back to the surface too quickly. This usually only happens during (improper) kiln drying, although if you tried really hard you could probably get it to happen in air-dried wood, too.

   -Steve

    

1. 
   JayS | Dec 06, 2007 04:55am | #2

   I remember asking this question once.  My understanding is that the drying of wood is intracellular dehydration.  That is the individual cells contract like raisins but are surrounded by a cell membrane and cell wall.  You can't get water back into the cells.  This is why a well seasoned pile of firewood will still burn easily when it has been out in the rain.  The water is all on the surfaces, which includes within cracks, but doesn't actually enter the material.

   Jay S.

1. 
   saschafer | Dec 06, 2007 05:05am | #3

   You can get water back into the wood, but it takes time. After all, water moving into and out of wood is what causes seasonal expansion and contraction. A quick dousing in a thunderstorm isn't going to do it, but leaving the wood at the bottom of a tub of water for several months or years certainly will.

   -Steve

    

1. 
   JayS | Dec 06, 2007 09:11pm | #5

   How then is it possible that companies have developed to salvage old growth logs that have been sitting at the bottom of various lakes for 100 years?  These are sliced into boards that are considered dry as far as I know.  Thanks.

   Jay 

1. 
   saschafer | Dec 06, 2007 09:19pm | #6

   "These are sliced into boards that are considered dry as far as I know."

   No, "bog oak" and other water-preserved woods still have to be dried. In fact, with many of them, the drying process is especially painstaking, as the chemical changes in the wood have made it more fragile.

   -Steve

    

2. 
   JayS | Dec 07, 2007 12:52am | #7

   Very interesting. Thanks.

    As far as a practical application of the concept of re-hydrating wood to reverse shrinkage I'm not sure how one would practically speaking, apply this.

   Jay

2. 
   BobSmalser | Dec 06, 2007 09:25am | #4

   Barns aren't dry, humidity-wise unless they are either heated or situated in a climate like Arizona.

   Check the moisture content at the core center before proceeding. 6-10% MC may be just fine for indoor wood in your climate, and I seriously doubt this wood is any drier than that. In my climate, a dense hardwood stored in an unheated barn loft would be between 14 and 18% MC this time of year, and take some indoor acclimatizing before being useful for furniture.

   Otherwise it'll take a while to stabilize thick stock at a higher MC, and after you start rehydration, until it is of uniform MC throughout its thickness it'll likely banana peel when ripped. The wood is stable now, so if you intend to alter the MC, I recommend you do the major machining before rehydrating.

   
   

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   Edited 12/6/2007 1:33 am by BobSmalser

1. 
   Boofey | Dec 08, 2007 12:48am | #8

   Thanks for the info on Moisture Content.  Not having a meter, I can't be sure what it is.  When I cut out the sound wood between the obvious cracks, I'll sometimes find internal cracks.  But even in the sound wood, when I try to turn wooden plates or even small bowls, the wood seems crumbly, almost powdery, and that's why I think it's too dry.  The full boards look so good -- clear, red cherry -- that it seems a shame there's not something I can do with the stuff.

1. 
   BobSmalser | Dec 08, 2007 01:47am | #9

   Taken all together, it sounds to me like the wood's crumbly because its lignin is gone, which has nothing to do with how wet or dry the wood is.Lignin (the glue-like substance that holds the cellulose of the wood fibers together) deteriorates from either attack by one of the rot fungi or from overcooking in a kiln. As has already been mentioned, your honeycomb checking is also consistent with overcooking.There's nothing you can do except salvage any good sections remaining and burn the rest for heat.

   Edited 12/7/2007 6:25 pm by BobSmalser