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Advice on drying wood for a project.

Started by Paschale, August 19, 2004, 10:06:43 PM

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Paschale

Hi guys,

I've got some ash that has air-dried for two years.  It's gotten down to between 10-12% and is now sitting in my garage/shop on my rack which is several feet off the floor.  I'm really itching to build something with it, and I've sort of rough cut some of the wood for a bookcase I want to build.  I was talking with Chet at the pig roast about this.  I've always read that you've really got to get the wood down to between 6-8%.  I was telling Chet that I'd measured some wood in the house--I've got an old storage box antique that was never finished--and it was measuring at around 10-12% too, so I began thinking that perhaps since the ash was dried down to the same level as this unfinished wood in my house, perhaps I could go ahead and safely start building without too much trouble, as long as I built into the design some accomodations for wood movement.

It was at this point that Chet explained to me for the first time the real reason why getting the wood down to 6-8% is so important and that is because it breaks the cells that expand and hold the moisture which really cause the problems.  I just sort of assumed that if the wood matched what was in my house, it was dry enough to build with.  After talking with Chet, he suggested I bring some of the wood into the house come fall/winter so the dry heat of my house will do the final drying out, which will save me a lot of frustration when a finished piece cracks.

All that babbling to get to the question.   ::)  I REALLY want to start building something with this wood sooner, if I can.  I have a root cellar of sorts in my basement which was really damp, so damp that I bought a dehumidifier just for this room.  It's small--like maybe 4x8.  I got a serious DH in there, and it's dry as a bone in there now, plus the room's always pretty warm because of the DH too.  Do you guys think this could be used as a sort of "kiln" to bring enough of that ash down to 6-8% to start building a project with so I don't have to wait until winter?

Also, I've often wondered about what they used to do in the "old days."  My parents still have a hope chest my Grandpa built for my Grandma.  If I remember, it's walnut with some birdseye inlay.  Back in the 20's and 30's, that would have only been air dried, since it was taken off the land, yet it's held up.  Plus, for hundreds of years, wasn't all lumber only air dried?  Is it the advent of forced air heat that's caused us so much problems, or did those old pieces of furniture just sort of dry out over the years, with common warping/shrinkage, etc. that just had to be repaired from time to time?  Makes you wonder about all the old furniture builders, like Chippendale, or even the Shakers--how did they deal with wood movement from air dried lumber?  A friend of mine is a luthier, and makes double basses for a living.  He uses air dried spruce, and just won't touch kiln dried at all.  It makes me scratch my head, since in a musical instrument, wood movement could really be a problem, yet he uses air dried.   ???  Can you ever really get away with safely building furniture with air dried?

Hmm...I suppose this really should be two separate threads (and shorter too!).  I guess I'm really curious about both subjects, and would enjoy getting some input on both accounts.

Dan M.

Y'all can pronounce it "puh-SKOLLY"

etat

sorry, i have no idea about your ash but i want to take a stab at guessing at the other.   i believe even in the 20's and 30's a lot of furniture used veneered panels instead of completely solid boards.  also most houses didn't have air conditioners and humidity controlled houses, thus 'perhaps' the wood didn't have to be quite as dry.  i'm pretty sure that their joinery methods, even then would allow for wood movement.  i have heard of cases where some of this antique furniture was moved from these older houses where it had sat for years without problems   when moved into a newer, humidity controlled houses i've read where it might develop problems with the wood or finish cracking.    
Old Age and Treachery will outperform Youth and Inexperence. The thing is, getting older is starting to be painful.

Ianab

Hi Paschale
You can build with 10 -12% wood, so long as you keep in mind that the wood may shrink a little more in the winter when your house is heated. Select designs with that in mind. Something like a simple bookcase should be OK if you think out the design properly.
This is a cabinet I've made from air dried Cypress. It's not fallen apart yet  ;) It was designed with some movement of the wood in mind though.


Your idea of putting it in the room with a dehumidifier should work. It's not like you are trying to dry it from green. Put a small stack of boards in there for a few weeks and see what m/c they settle down to.

Ian
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Norm

I think using your dh to finish dry it will work just fine, use a small fan to keep the air moving. Since your wood is already down in moisture so low I'll bet it won't take long to get down to 8% moisture which is what I'd shoot for. Keep track of the drying time as I'd be interested how long it takes.

MemphisLogger

Dan,

It is very typical that interior wood be 10-15% MC in the summertime. Depending on your locale and how you heat your home, MC may go to maybe 6 - 7% in the winter.

If your Ash is the same MC as the wood in your house right now, you'll be fine. The point of cellular collapse is more like 20% in most species I'm aware of.  

The key is building to accomodate seasonal expansion and contraction of the species your working with. That's why solid doors are made with "floating" panels and solid table tops are fastened with elongated holes, sliding cleats or "figure eights".

Each species "moves" at different rates in both the tangential and radial planes. Wood does not shrink appreciably in length. Calculations can be made for how much the species will move if you know the range of humidity the piece will endure. A calculator is available at https://forestryforum.com/board/index.php?action=toolbox The original Wood Calculators<<<<  

The only thing I'd worry about with Ash is that it may harbor powder post beetles which can only be eradicated by heating the wood to 130 degrees plus for more than 48 hours which is typically accoplished in the kiln at the end of the dry cycle.

If you need any help on how to build to accomodate wood movement, feel free to ask!

 :)  
Scott Banbury, Urban logger since 2002--Custom Woodworker since 1990. Running a Woodmizer LT-30, a flock of Huskies and a herd of Toy 4x4s Midtown Logging and Lumber Company at www.scottbanbury.com

Buzz-sawyer

Hey Dan
Some very good points and I think they are worthy of exploration.
Obviously all primitive furniture i.e folk , mountain, homemade is air dried...as well as much of the fine older furniture that is hundreds of years old.
If you throw a chair in the creek it will attain the humidty level of the creek , likewise in a house, but,......... I believe the exception is that, once dried it will rise in relative humidty ony to a certain point...maybe20% ? In other words it wont return to 80-100% if that is your humidity level.
Dealing with insects, and setting pitch are a side issue to the best starting point for the moisture content of material to build furniture with.
As I see it , the key is, shrinkage in joints that will occure in your house ,
( if it is drier inside than the wood you drag in there).
Thats about it!!! If you build a nice tight jointed table and stare down at your rasberry cheese cake and see cracks in your fine works joints, you will wig out!! So shrink it as much as possible then it will remain tight at the low humidity and tigher in the high humidity.........unless you get cheese cake in the joints then you wont even care 8)
    HEAR THAT BLADE SING!

Fla._Deadheader

  How about if I throw a bucket of water on this dry wood topic  ::) ::)

  I recently saw a table that was an oval shape, and it had a border around it. It made a contrasting effect. How could that be constructed to not split the border while expanding a bit from MC changes ???  Elongated holes will allow for the inner part of the table to move, so, what about the border??? Will it crack???
All truth passes through three stages:
   First, it is ridiculed;
   Second, it is violently opposed; and
   Third, it is accepted as self-evident.

-- Arthur Schopenhauer (1788-1860)

Paschale

Thanks for the input guys!  I'm going to go ahead and give this a whirl.  Thanks for the suggestion on the fan Norm, and I'll definitely let you know how long it takes to get down to 6-8%.  And Ianab:  nice cabinet!  :-)

UrbanLogger, I'm sure I'll take you up on your offer for advice once I begin building this thing.  The design is an arts and crafts style and utilizes through tenons.  From all I've read/seen, the key is just to glue in the center of the tenon to allow for some movement.  Since it's summer, I'm thinking I should make the joint fairly tight too.  Any thoughts on this so far?

Also, you mention powder post beetles and ash--I do have some boards that show evidence of old ppb (at least I think it's old).  They were close to the bark.  The boards I've selected are free from any evidence, so I'm hoping I'm OK.

Hopefully I'll be able to start building this thing in earnest in the next couple of weeks, if all goes well.  And if it doesn't work out, there's always raspberry cheesecake to console myself with, right Don?   8)  Speaking of cheesecake, I made a blueberry one last week with fresh berries.  Tasty, but I don't think that the good Dr. Atkins would approve.   :D :D :D
Y'all can pronounce it "puh-SKOLLY"

Hokiemill

Hey FDH, sounds like a veneer job on a stable substrate like mdf.  If you got a close look and it was definitely solid, sounds like they're gonna have some problems.

MemphisLogger

Deadhead, I second Hokiemill's thoughts--the only way I would do a flush-framed oval is with a stable substrate. Now if you just had to do a solid wood framed table then the frame would have to be grooved/dadoed to accomodate the movement but this would require that the frame be "proud" of the surface of the table top.

Paschale, with thru tenons, you can really forgo the glue altogether if you wedge them but even when I do wedge them I use glue too for redundancies sake.

When gluing them, I apply glue to the full width of both cheeks but not the top or bottom. The reasoning here is that only the long grain to long grain surfaces will hold anyway--the end grain at the top and bottom of the mortise won't glue worth a DanG.

As for accomodating movement in the tenon, make sure that your tenon isn't too wide--no more than 3-4" for most species--and use yellow glue as it will "creep" (stretch with expansion) to some extent. If I need to join a piece that wants a wider tenon, I cut 2 with a space in between. Same thing goes for any tenon that is thicker than an inch or more.

PPB holes look the same as other small borers that would be at work in wet wood. Most of these beetles will die and/or abandon the wood once it gets down below 25% MC. The PPB will come to the wood AFTER it's below 25% and would be distinguished by little piles of "frass" appearing on or under the dry lumber.            
Scott Banbury, Urban logger since 2002--Custom Woodworker since 1990. Running a Woodmizer LT-30, a flock of Huskies and a herd of Toy 4x4s Midtown Logging and Lumber Company at www.scottbanbury.com

sigidi

Paschale,

I think you're right about the old time wood, and others about the new fandangled airy conditioners!!

The biggest difference is the old time 'tradesman' they REALLY knew how to work wood, most folkes nowadays - myself included, make the project but might be lucky to have a tenth of their understanding of the timber (insert respectful, sombre, nodding smiley)

Just my interest free two cents. :D
Always willing to help - Allan

woodbeard

The powder post holes will be little pinholes. Ash almost always gets some bigger boring insects under the bark. They are the kind that go away when the wood dries, just wondering if that's what you are seeing- about 3/16" dia, or so?

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