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Discussion Starter · #1 ·
Yesterday I was finally able to pick up the lumber that I need to make a new coffee table top. Just about all of my lumber is rough cut and I do all of the milling myself. In the past I’ve used lumber that has been in my shop for a while so I've never had to ask this question. This time, the lumber that I purchased is needed as soon as possible for this project. My wife has told me that, so it’s true. The lumber yard stored the lumber in an air conditioned warehouse. My garage shop is not air conditioned but I do have a dehumidifier. I keep the dehumidifier set to 60% and it rarely runs even though the outside humidity, here in Florida during the summer, can reach 90%. Like breathing water.

I always rough mill and cut my project pieces oversize and let them re-acclimate to the shop for a day or two before I finish milling and cutting to final size.

The lumber in question: I purchased two 8/4 x 7”x9’ black walnut boards (and they are really black), one 8/4 x 5” x 7’ hard white maple, and one 4/4 x 5” x 8’ birds eye maple. All boards have been kiln dried. I will resaw the black walnut to end up with final size between 3/4" - 7/8".

Now, my question. Since I just moved the boards from the lumber yard’s air-conditioned warehouse to my garage shop, how long should I wait for them to acclimate to my shop before I start to rough mill them?

As always, thanks for your help.
 
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David - Machinist in wood
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Do you have a meter to check MC, Barry? I buy Walnut in the rough directly from the sawmill where he kiln dries to around 8% to 10% and then I bring it into my climate controlled shop - just the opposite of your situation. Since I buy in advance I don't usually cut newer wood for a week or two, often longer.

When I need it right away I always check MC when I get it home and then let it set 3-4 days and check again. If it hasn't changed I go ahead and use what I need. If it's changing, and the application is critical for sizing, I'll wait until it stabilizes. That could be another 3-4 days or a bit longer.

Hope that helps.
David
 

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Barry; if I understood the explanation your shop is more humid than the warehouse? So in theory the wood is drier now than it will be eventually? Shrinkage is the normal issue and that's not going to happen so why not carry on.
We've often talked about bringing hardwood flooring into the rooms where it's going to be installed, a few days in advance, for the opposite reason under discussion, but I can't remember ever waiting for flooring to swell..
Drying might cause warping but what's gaining a couple of %age pts. of moisture going to cause?
A LOT of water would almost certainly cause buckling of flooring, but that's because the floor boards are restrained and have no room to swell.
This is a very interesting situation; I'm looking forward to hearing about other's experiences with wood gaining moisture (humidity).
 

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I just thought of a possible downside: if you created a tight fitting mortise and tenon joint at the lower %age than if both the mortise and tenon swelled imperceptibly, than it's possible the joint partners may no longer fit in the future...unless the joint was assembled immediately after completion. Not ever coming apart!
 

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Discussion Starter · #6 ·
I like David's approach. It does make sense since you're waiting for the wood to tell you when it's ready to be worked rather than you guessing. I've considered getting a moisture meter in the past but the good ones seem to be a bit pricey. Being on a fixed income isn't all it's cracked up to be. Is there such a thing as a good inexpensive moisture meter or is that an oxymoron? Which ones do you recommend?

Here's something else that your postings have brought to mind. I have thermometers with humidity gauges in my house and in the garage. Right now, the house is at 52%, the garage is 56%. The range since midnight last night is house 50 - 54 and garage 56 - 60. Is this enough to make a difference if I build the table (39" x 39") in the garage and then bring it into the house, where it will live, to attach the base?
 

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It's going to change with the seasons anyway, Barry. We have a large solid wood buffet that lets out a sharp 'crack' at least twice a day, as the temp/humidity changes.
When we first bought it (at an Estate sale) we brought it home and put into our dining room of the place where we lived at that time (1983?). The house was electrically heated, and we didn't have a humidifier. Within two days one of the solid wood side panels cracked... :(
Bought a humidifier next day...took a week for it to stop running non-stop, ie the humidistat was finally satisfied. Betcha it went through 5 gal. of water!
 

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David - Machinist in wood
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I don't think that's enough difference to have an effect on anything. Acoustic guitars players have to be sensitive to the humidity and if you're talking 4% - 5% difference then that's really insignificant. Unless you're using a sling psychrometer for really accurate readings my guess is whatever you're using for testing the humidity may not be that accurate. Could be, but either way it's close enough.

The moisture meter I use is a General from either Lowe's or HD, don't recall. Seems like it was less than $30 and I went for the pinless. It may not be as accurate as a high dollar pin type meter but since I need to test thin wood for acoustic guitars I can't really use pins. My sawmill guy has both types and we've tested both his meters against my pinless and all three read within 1-2 points each time we tested.

When I set a board on the concrete shop floor and come back the next day to find the floor wet under the board I don't really need a meter to tell me that's a board not ready to use. And when I pick up a piece of rough 4/4 Walnut 8" wide by 8' long and it's a really heavy board then it's still wet. If it's light then it's probably dry enough to use. The moisture meter backs this up and gives me a number for reference.

One thing I do with each load I get, though, is to sticker them in the shop. Because I don't have much space and can't store much I usually only get about 6-8 boards and they're stickered until I use them. It's also easy to lift a few and check MC without really moving any boards.

David
 

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Discussion Starter · #9 ·
Ok, you've convinced me. New toy, didn't take much convincing. I've read a number of reviews for 2018 and have come up with two meters. One with pins and the other pinless. I'm leaning towards pinless since if i want to check a milled piece of wood I don't have to put any holes in it, even though the holes are tiny. However, I'd like the one that is quickest and easiest to use, assuming both are reasonably accurate. These are the two:

Pin - https://www.amazon.com/Calculated-I...r=8-1&keywords=moisture+meter+for+woodworking

Pinless - https://www.amazon.com/d/Moisture-M...r=8-4&keywords=moisture+meter+for+woodworking

Which one would you choose or do you have another recommendation?
 

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David - Machinist in wood
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I agree with both you guys; mine is a pin type and that stops me from using it sometimes when I should! I just hate to put holes in a planed surface.
In theory at least you'd think you'd be able to come up with a meter that has cables allowing a user to check the continuity/resistance right through the thickness of a piece of wood, ie front to back(?).
Wouldn't that be more accurate than across the face side? Also, for more accuracy, one would need a sample of the specific species of wood, dried of course, as a reference reading.
My gut feeling, having used mine for years to determine 'condo rot' issues, is that they're just an indicator. They seem to be more accurate at the lower end of the scale.
 

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If I remember correctly, and there's that chance I'm not these days, the meter calculates based on resistance and type of material. The thickness of the board will certainly have an affect on reading I would think. A 4/4 board versus a 8/4 board may read the same or close surface % but at the center may be a fair bit different. A thought would be to cut an end piece and read that freshly cut piece at different depths, especially the thicker boards but then I think it does matter between ends and center as I would expect it to dry faster at the open ends. So then I think maybe rough cutting the boards allowing for movement would allow more accurate readings and also allow the wood to acclimate faster if needed. Now this may be mindless ramblings but in my mind (don't go there if not absolutely necessary) it makes sense to me.

I also have to wonder if different woods expand/shrink differently depending on the species? So what is rule of thumb here? Do you acclimate based on a set range or by the average humidity of where the piece will be placed. What do fine furniture makers use as they have no idea where their products will end up? I suspect they have an acceptable range % and use joints that are most likely not to fail but then again that's all speculation on my part.
 

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I also have to wonder if different woods expand/shrink differently depending on the species? So what is rule of thumb here? Do you acclimate based on a set range or by the average humidity of where the piece will be placed. What do fine furniture makers use as they have no idea where their products will end up? I suspect they have an acceptable range % and use joints that are most likely not to fail but then again that's all speculation on my part.
you asked...

.
 

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Frank
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I use a lot of Walnut that has to be re-sawed to get the boards I want. I usually saw the boards to oversize and before planing, I place "stickers" between the boards and let them acclimate to the garage for around two weeks. I use the Timber Check Moisture Meter shown below. Here is a link to where it can be purchased and a picture below.

https://www.ebay.com/p/Comprotec-Ca...eter-Ship/18012052170?iid=263799519488&chn=ps

The pins on the moisture meter are not a problem because I check the boards before planing or at the ends. You will see that this unit is more expensive, but I wanted a meter that I could trust to give me accurate results. I have had it for many years.

I have just had my first problem with wood swelling. I completed a blanket chest which can be seen in one of my posts. I took off the lid and removed the bottom boards so my friends could carry the chest from the garage to the house. They were out about 2 days. When I tried to put the bottom boards back, they had swelled by approximately 1/16". I have not yet put the last board in. I am trying to see if it will dry out enough to insert with out taking to the garage and removing 1/16".

Frank
 

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David - Machinist in wood
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I don't like checking boards from the end because they just about have to dry out quicker than the bulk of the board. And that's one reason I got a pinless meter - I can check anywhere and not put pin marks in the wood. I know the pin type is more accurate, although the way technology keeps advancing that may not always be the case.

David
 

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Discussion Starter · #19 ·
Reading all of the posts, along with Stick's great detail, has given me an idea. The Walnut lumber for the table top is 8/4 and 9 feet long. Since the boards are rough sawn, I used a hand plane on part of the board to see what the figure looked like. More like skip planing. I'll do the same to the rest of the board. I ordered the pinless meter that I referenced in post #9 and it'll be here Sunday. If I can use the whole board, I'll wait until the moisture readings are the same on both sides of the board and consistent for a day or two. Then I'll cut the board into 3' lengths which is the rough cut for the 33" final boards. I'll then take a reading across each of the 4 cut ends to see how the moisture varies across the cut. Based on that I'll either resaw each piece to end up with the 6 boards I need for the top or wait a bit longer. The question is, since I don't expect the moisture reading to be the same across the entire cut, how much of a difference is acceptable before resawing?

Once I do resaw, I'll let he boards rest for a few days before the final milling and glue up.
 

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Discussion Starter · #20 ·
Stick - I copied the 3 pdf's to my woodworking library on my PC. Two of them are good but the MOISTURE CONTENT AND MOVEMENT pdf has the right side of the page cut off. I don't know if it's me or the pdf. Would you please check that and, if it's not me, please repost it. Thanks.
 
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