Length of time required for air dried lumber to acclimate to my shop?

[Jim Andrew]

About a month ago, I sawed some lumber. Needed a place to air dry it, so moved this stack home to the shop lumber storage room. Replaced it with some green lumber. I was heating the shop at the time, weather has improved so I put the dehumidifier to work, and it is still collecting a little water every day. Have no "accurate" moisture tester, so just thought I would ask about how long do you think I should wait before planing this lumber? This stack is about 2 years air dryed, so assume about 12% when I brought it in.

[Mark Wooden]

If the air dried stack was outside 2 years when you brought it into a heated space, depending on where you live, I'd think that the MC was closer to 20 percent when you brought it in and if indoors for a winter maybe 10-12 percent.
If you can, put the stack in a closed up area with the dehumidifier running for a few weeks, flipping the stack often. Then look for an inexpensive moisture meter. I made a poly room in my basement once to do this that got 5/4 oak down to 6-8 percent in a little over a month. Used a lot of electricity though........

You can plane the lumber anytime you want, it'll still dry, probably faster. But you will lose dimension so plane large.

[Danny Hamsley]

Here is some data. Red oak, air dried and planed to 13/16". Equilibrated to about 9.5%. Based on this, I would give it about 1 month.

Edit: I attempted to attach a graph, but was unsuccessful.

[ryan paulsen]

Instead of guessing the MC, why not just measure it? Take an ~1" strip across the entire width of a piece (preferably not from an end) and weigh it in grams. Microwave on low for a minute at a time until it stops losing weight, but before it burns. Original weight - oven (microwave) dry weight = weight of water in the wood. Weight of water over oven dry weight x 100% = your MC. It easy, even I can do it!

[Lee Schierer]

When you plane it be sure to remove equal amounts of material from each face to prevent warping and cupping.

[Jim Matthews]

If you work slow, like me, ten days is plenty.
By the time you get most of the boards
milled, they're dry enough for stable joinery.

If you work fast, you might need to wait a little longer.

[Larry Edgerton]

I have a 1000 feet of Ash under cover, been two years stickered. We had a cold dry winter and I just checked it and it was down to 12%. I figure that is as low as it is going to go in the barn and will start using it this year.

[bill tindall]

The only way to get an accurate measure at low moisture content is the procedure described. Using the MW has it s problems though. I use the kitchen oven set at 220 F (100C) The test piece will reach constant weight in a couple of hours. The rate at which lumber looses or gains weight is so dependent on many factors (air movement, air humidity, temperature, species, etc. ) that it is meaningless to ask how fast your lumber will dry in your situation.

[Prashun Patel]

+1 on getting another moisture meter. Mine's cheap and while I don't trust its reading in an absolute sense, I calibrate it to known dry wood, and known green wood before testing my target. At least you'll know relatively how dry it is - a lot more than all of our speculation here based on our own experience and climates.

[Tom Deutsch]

About a month ago, I sawed some lumber. Needed a place to air dry it, so moved this stack home to the shop lumber storage room. Replaced it with some green lumber. I was heating the shop at the time, weather has improved so I put the dehumidifier to work, and it is still collecting a little water every day. Have no "accurate" moisture tester, so just thought I would ask about how long do you think I should wait before planing this lumber? This stack is about 2 years air dryed, so assume about 12% when I brought it in.

I’m having trouble with the timeline as described here. You sawed it a month ago – meaning you milled it to dimensional size from larger logs? Or was it already at 5/4 or close? In other words – what state was it in for the 2 years mentioned later – logs outside or stickered boards under cover. (To me outside means not under cover.) Sorry to sound like a lawyer - LOL.

[Gary Yoder]

I’m having trouble with the timeline as described here. You sawed it a month ago – meaning you milled it to dimensional size from larger logs? Or was it already at 5/4 or close? In other words – what state was it in for the 2 years mentioned later – logs outside or stickered boards under cover. (To me outside means not under cover.) Sorry to sound like a lawyer - LOL.

I think you misunderstood. He needed a place to store the new lumber so the two year old lumber got moved inside.

[Scott T Smith]

Jim, you did not mention the species or thickness of the lumber that you're working with. You also did not mention the RH% that your dehumidifier is set to. Coupled with the initial MC%, all of these factors will influence the correct answer. Your 12% MC estimated after air drying for two years is about right (unless you are in Arizona!)

To speed the process up, about a week or so after bringing the lumber into the shop skip joint/plane the material to around 1/8" thicker than final target. The first week or two of grace period will allow it to cup a bit if it is so inclined, and by skip joint/planing it down you are speeding up the acclimatization process due to both the reduced material as well as the smoother surface (lumber dries a tad bit faster from a smooth surface as opposed to a rough one).

For oak, Danny's advice is spot on.

[peter gagliardi]

(lumber dries a tad bit faster from a smooth surface as opposed to a rough one)

Scott, not so sure about that. Rough lumber has more exposed wood fibers in given area, therefore should dry faster. I'm almost positive I learned this about 20 years ago while reading the "wood bible" Bruce Hoadleys text "Understanding Wood" .
I don't have it near, or I'd check.

[Danny Hamsley]

Peter,

It is logical, but Scott is right. The rougher surface traps moisture vapor versus the smooth surface where air flow moves it away from the board more efficiently.

[Jim Andrew]

The boards are walnut, sawed 4/4. The dehumidifier is set as low as it will go. Have been emptying it every day, now it is not collecting a lot of water, so assuming the boards are getting dry.Yesterday there was about a quart of water in the tank. Thanks for the replies.