Kiln dry wood

I am no expert on this Albert, but wood generally will assume the moisture level of its surroundings. I believe it is called moisture equilibrium. Even if it is finished, it will lose or gain moisture to achieve balance with the ambient moisture content of the air. Wood in the north seesaws more radically, IMHO, due to the alternate heating and cooling extremes and the varying moisture in the air.

Leif

All woods absorb or loose moisture from their surroundings, some more than others. All wood movement is due to this property. Movement is mostly across the grain, rather than along it. This is the reason the floating panel was invented in europe some time ago, so that panels over 8-10" wide would not crack. In frame and panel construction, a panel is floating in a groove around the inside edge of a rail and style frame. Wether a particular piece of constructed wood will crack or not has more to do with the joinery techniques, where the wood is prevented by the joinery from expanding and contracting. Of course, with the advent of engineered wood, such as plywood and particle board, large solid panels are possible without allowing for movement. Since with plywood and particle board the grain runs in multiple directions, the size is relatively stable. Thus, veneer covered ply has become popular for furniture with the home woodworker where large panels are needed.

Gold mine of material here for free.

information will be in chapter three, where tables showing theEquilibrium Moisture Content (EMC) of woods at a specific Relative Humidityare located.

Thanks for all the help, it really helped me a lot.

Thanks,

Albert

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I had a talk with the guy again, he seems to have 38 years experiance in wooden antique clocks. He tlod me that if you dry it until 6 - 8% moister, something happends to the wood structior. Inside the wood it will no longer become 14% by sucking up from the atmospheer. But the surface of the wood will still take some moister in but not the entire thickness.

Anybody familiar with this? Thanks. Albert

Albert, this line of thinking goes against all that I've ever read on the subject. Frankly I've never heard such a thought before.

As I understand it, the wood will absolutely take on or give off moisture to match the surrounding ambient humidity from the outer surface all the way to the center. It may take a long time to "refill" the center portion of kiln-dried stock from very low moisture content, but given enough time in a higher humidity environment it'll reach equilibrium eventually. A finish coat will slow that process down but it's inevitable as far as I know.

One of the advantages of using drier than equilibrium MC for the planned location is that joints would tighten after it's assembled - if assembly occurs before the wood regains that is.

Do you have a specific question concerning the application of kiln-dried vs. air stock? (too lazy to look up your original post)

Hmmm, I'm thinking, "Entire woodworking world except for one guy believes that any wood except maybe petrified wood will freely exchange moisture with the atmosphere until it reaches equilibrium...probably the one guy is operating on a combination of good luck and 'Just-So' story he wrote himself." Not to belittle the fellow at all, but it's not hard to pass along (or "discover" for yourself") mis-information. I've worked with wood for over 30 years and have never heard anything like that. What the heck, maybe _I'm_ wrong.

(Going for the extreme example which illustrates a principle most clearly.)

Is he saying that tossing the wood into the ocean won't result in the inside of it eventually regaining moisture? Water is basically thick air and serves as an extreme example of ambient humidity.

I do not want to cut the guy down, but I'd like to hear from him what this 'something' that happens to the wood structure is.

Bill

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subject. Frankly I've never heard such a thought before.

to match the surrounding ambient humidity from the outer

center portion of kiln-dried stock from very low moisture content,

equilibrium eventually. A finish coat will slow that process down but

location is that joints would tighten after it's assembled - if assembly

vs. air stock? (too lazy to look up your original post)

The original subject was timber (Mahogany) dried until 14%, then made furniture of it. After arrival in Canada because of extreme differences between winter & Summer, it will crack. But also absorb a lot of moister. But when you dry it 6-8%, it will not crack and only the surface will take up some moister. Maybe he also means if you change timer quickly into furniture and finish it, it will not extend much. Although you never finish the furniture for 100%. The inside of let say a partner desk you only finish the parts you see. So from all your comment I still do not understand what this guy is saying. Anyway maybe continuing story.

Thanks for all the comment.