Wood Rest Confusion

[David Ragan]

While planing a bunch of cherry this AM, I am wondering-what's up with letting wood rest?

In the past, I was a big believer in it. Letting the inner tensions work themselves out following removal of a significant portion of the wood. No doubt it happens.

Last night, I was watching Mark Spagnuolo on YouTube about milling stock-he said (wisely, I'm sure) let the wood rest a week after milling, it will reach a state of equilibrium, then, mill it again. I understood this to mean do the majority of the milling, then the tweaking a week later-starting over with jointing, etc (In my limited experience, I have never approached it like this)

So, I'm sitting in the 'deadly recliner' last night, watching Mark and ask.....Why a week?

--Pretty much immediately, any stresses become manifest. I have had the experience of ripping on the table saw (somehow-w/o the splitter) to have the wood pinch and stop the saw blade
--Then, when I go into the large bundles @ the lumber yard, some of the lumber (after I get them home and they are released from the bound confines of the shipping bundle) after a few days will assume it's 'preferred state' ie, cup, bow, etc
--When beginning the milling process-cutting stock to length prior to jointing/planing--the wood may distort again (after just a few minutes to hours, I guess)
--The following thought is foremost in my mind: Moisture content? Doesn't it take about a year per inch of thickness for moisture to equilibrate? Doesn't this imply that one should wait a year for each inch of thickness? Clearly, this is an unreasonable time frame....

There is not a definitive answer, I'm sure. I will go on the record in agreement with Mark

I guess my take home at this point is: that most of the milling can occur in a couple of days, to wait for final milling of a week. I have the good fortune of normally using FAS hardwood, in thicknesses of 3/4 to 4/4.

Any thoughts? Thanks, David

[Andrew Pitonyak]

An entire week? Had not heard that before. That said, you want to give it time to first acclimate to your shop. I suppose that it also depends on the type of wood and how much you mill off.

I expect that the primary issue (if you think one week) is related to moisture equalization. I expect that the general workflow is similar to the following:

1. Cut wood over-size to rough require dimensions.
2. Mill wood to about 1/8" of desired thickness
3. Set aside to acclimate / equalize. The wood should be stickered at this point, don't just lay it flat on your bench or (gasp, even worse) that cement floor.
4. Wait a day or two.

That said, I expect that mark is better informed than I, or perhaps just more cautious.

I am not familiar with internal stresses causing continued deformation over the course of a week (from already dry wood). Not saying it does not happen, just that I don't expect it. I will say that if it has not moved in one week, then you are likely pretty safe.

[Myk Rian]

I'll let it set a day or 2 before using milled stock.

[John TenEyck]

Most of the wood I use has been in my reasonably well climate controlled shop for weeks/months/years before I use it. I never use wood that hasn't been there at least a week, or doesn't read within 1 - 2% MC of wood that's been there for months. With that as preface, I've never seen a benefit of letting milled wood sit longer than 24 hours to "adjust". Generally, I mill it to final dimensions straight away and use it.

Some folks may have to wait longer than I do because their wood isn't at EM with their shop, and/or their shop isn't climate controlled. Whatever works for you is the right approach. I even read in FWW a year or two ago that you should throw your pre-milled wood up in the air and let it fall on the floor to relieve internal stresses. Really? Do I do that once per inch of thickness? Just goes to show you that everyone has their own closely held beliefs as to what's right.

John

[Ellen Benkin]

Gosh, a week seems like overkill. I'm lucky if I mill oversize, sticker, and wait overnight.

[Charles Li]

Throw me in the confused crowed. There was an episode where Mark (thewoodwhisperer) was cutting 2x4's or something similar for a lumber rack and said to secure it to the wall immediately after cutting. Obviously this isn't wood for fine furniture but if the wood is going to move that much why not wait - like he recommends in other scenarios?

[Mark Bolton]

I'm with Ellen, but the "theory" is that no matter how long the material has been in your shop when you remove material (even if you remove equally from all sides) you have exposed material nearer to the center of the board which is slightly higher MC as well as possibly removing or exposing some tension.

The commercial wood industry would grind to a halt if waiting a week had any benefit.

On the flip side don't put much weight on spagnolo. Even though he was with marks he learned most everything on his followers dime and that of his sponsors. He is just a figurehead making money off the hobby. I always remember watching his early shows when I couldn't find anything to watch and he would say, and make, some of the most rookie mistakes while he is supposedly teaching woodworking. He once cut his pins and tails on the wrong parts of a dovetail drawer (so it was sliding sideways and the joints provided zero benefit) and his viewers pointed it out to him on his chat thing.

He has done a masterfull job of getting a sponsor paid for shop and I'm sure he and his wife have profited handsomely from it. But a skilled woodworker he is not.

Something to watch when there's nothing on though.

[David Ragan]

Then yesterday when my pile of milled cherry boards hit the floor (and my leg), it was a good thing? Too funny!

The part I like best is the one about the commercial wood industry....Yes-*everything* ultimately comes down to money. True, I can't see these professional folks with a job to do waiting around a week to get on with it.

Then, acclimate to my shop? This exact thing is what has bothered me ever since I started using tools on wood--What's the piece going to do when it gets into the dry environment of the house?

I have a humidity gauge in the shop, and it reads in the high 50s year round (Atlanta with dehumidifier).

I'm going to grab up those dropped instantly distressed boards in a few and take them right on down to probably ~7/8". Yes, I am going to start all over with the jointing, etc. I do love it, though.

[Mark Bolton]

Then yesterday when my pile of milled cherry boards hit the floor (and my leg), it was a good thing? Too funny!

The part I like best is the one about the commercial wood industry....Yes-*everything* ultimately comes down to money. True, I can't see these professional folks with a job to do waiting around a week to get on with it.

Then, acclimate to my shop? This exact thing is what has bothered me ever since I started using tools on wood--What's the piece going to do when it gets into the dry environment of the house?

I have a humidity gauge in the shop, and it reads in the high 50s year round (Atlanta with dehumidifier).

I'm going to grab up those dropped instantly distressed boards in a few and take them right on down to probably ~7/8". Yes, I am going to start all over with the jointing, etc. I do love it, though.

Well,.. worrying about what it is going to do when it leaves your shop is a good thing. Thats a lot different then letting something sit in your shop for a week after initial surfacing. I mean Im not going to say someone working on a very critical project (door building comes to mind) isnt going to be very cautious with material prep. but again the wheels of the machine have to turn. It actually is a truth that when you remove material you are either #1 exposing material that is at a slightly higher MC #2 exposing, removing, or re-distributing, the tension in the material. But for the vast majority of work its inconsequential. If I were building doors, yes I might wait a day or so. Likely not a week.

But your concern about what your work is going to do when it LEAVES your shop is a valid concern. If you run an un-conditioned shop (most small production shops) its a major issue. If your producing work in the damp summer months that is then going to be installed in a conditioned space that fall your potentially in for some surprises.

I was more speaking to waiting a week for the wood to "feel out your shop" after you skim a little off each face. Ive just never seen the need.

Just my 0.02

[Peter Quinn]

The year per inch rule is from green, varies by species, and has no bearing on well seasoned or KD lumber. How long to let the wood acclimate is way more complicated if you want to be precise than a rule of thumb from some show on the internet. The wood whisperer is in Pheonix...its pretty dry there no? Like always dry. Maybe every time he cuts wood it starts to dry more? I have no idea about that climate, but in mine things are highly variable. Weather in New England changes by the minute. We go from flood to fire danger in 12 hours. What do you suppose that does to the wood? I have a monster dehumidifier in my shop, keeps things very stable on an annual basis. But I store wood elsewhere, buy wood form different yards with more or less climate control, I've seen KD lumber come in lumber bags on a tractor trailer, bags were leaking, lumber is less than dry. My point is the variables are many, so the best rule of thumb is keep your eyes open, develop experience in your environment, in your own particular shop. You have to be a sort of amateur scientist to figure this puzzle out. And once you get your lumber flat......join and glue it quick before it moves.

I like Marks comments about commercial wood working, whole different thing from boutique furniture making. If I'm going to spend 200 hours finessing a small pile of lumber largely by hand, why not let it acclimate and rest a bit. At work I'm often cranking out custom built ins that involve pocket screwed face frames glued to plywood carcusses that are screwed together. The whole mess will get scribed to sheet rock and screwed to framing....not exactly museum quality work but I like it. If my boss caught me stickering lumber for two weeks I'm not sure how he'd react, but proud and happy are not among the list of possibilities for sure.

All that said I'm careful both at work and at home how I let my lumber rest while I'm working it, and I usually will mill in two stages when I have that luxury, putting at least a few days and as much as a few weeks between initial milling and final dimensioning. Sometimes the wood actually benefits from it, other times it just makes me feel good.

[glenn bradley]

I have the good fortune of normally using FAS hardwood, in thicknesses of 3/4 to 4/4.

Any thoughts? Thanks, David

I wouldn't expect much trouble starting with that material as a base. I'd say you're doing fine. When I resaw some thick material to get some 5/4 boards out of it I will let these set around quite a wile before I use them on a project. When I resaw some 6/4 or 5/4 to eventually end up with some 1/2", 5/8", 3/4 or 7/8" stock I will mill close, wait a few days and then mill the parts to final size assembling them as soon thereafter as is reasonable. Others will do differently depending on their stock source, their environment, their construction techniques, etc.

[Scott Brandstetter]

I'm sure everyone else has answered your question but I had to respond to the "deadly recliner" comment. Not sure exactly what you mean but I think I got it. I have the same recliner. I have a small table on each side, pad of paper and pencil ready to draw plans, coaster for good Ky Bourbon, and of course, the notebook computer to look up random thoughts as they enter my mind.

Sorry, this hit a funny bone. May be way off on this one.

[David Ragan]

You picked right up on the 'deadly recliner'.

That is actually from another gentleman on these Forums-Charlie P. A kind and wise soul. (I have never had an original thought.)

As for the thread-I am going to mill twice (two stages?) from now on. It was evident to me yesterday that there was indeed some movement. Am very well pleased with the suction; and uniform thickness of my boards.

I will take design considerations first. If there is anything that needs attention after the panel is assembled (a whole nother thread), I'll deal with it.

[Kent A Bathurst]

Most of the wood I use has been in my reasonably well climate controlled shop for weeks/months/years before I use it. I never use wood that hasn't been there at least a week, or doesn't read within 1 - 2% MC of wood that's been there for months. With that as preface, I've never seen a benefit of letting milled wood sit longer than 24 hours to "adjust". Generally, I mill it to final dimensions straight away and use it.

Do this.

Get it acclimatized to your shop - I usually am in the 2 - 4 week range, depending on where the wood is coming from: Local supplier, who has had it for a while v out-of-state supplier, etc.

I do what John says, when I can - mill to final dimensions whatever I am going to be able to assemble that day. Otherwise, I mill +1/32 for short stuff, up to + 1/8" for longer stuff, and wait at least overnite. I don't wait longer for the wood to adjust, I wait longer because I can't get to it any sooner - overnite is all that I think it needs. I don't sticker my stuff - I stand the pieces on edge with a couple inches gap - but that is just to avoid fooling with the stickers. My TS with all the tables added is about 72" x 72", so I have plenty of room.

[Andy Pratt]

I have limited storage space for lumber in my shop (2-3 projects ahead is about all I can fit) so I have a good amount of experience with this. I work with primarily northeastern hardwoods, air dried and kiln dried as sources.

My rule for best practice is that all wood needs to be stickered in my shop at least two and preferably 4 weeks before I start working on it. This is assuming everything has been properly dried prior to this and hasn't been out in the rain or anything odd like that etc. When I have violated the two week rule I usually end up regretting it. I humidity control my shop to be at "average" humidity for my area. An additional but equally important rule is to do your machining for anything important the same day you do your joinery for the same items. If you do these two things you don't need to do your machining in two batches.

Occasionally you can get away with not waiting the required time (if the wood happened to be stored in a place just like your shop before you bought it, for example) but as a matter of practice you really should let it rest a few weeks in your shop before using it if you don't want to eventually have a really bad experience with something.