How long to let wood acclimate after resaw

[Matthew Curtis]

I have just resawn some 8/4 cherry for a end table. The cherry has been in my shop for over five years. After I resawed it I stickered and put some weight on top.

My question is how long should I leave it this way before surfacing to final dimensions? I don't want any surprises later with it twisting. Thanks

[Mark Carlson]

I always mill my stock in two steps. Rough to slightly oversized then final with a week in between usually because I'm working just on the weekends. If I have to resaw it kinda depends. If the boards are wide and moved a lot a I will wait to see what happens. If the resawn boards are narrow/smaller I might go immediately to rough milling. Also depends on my schedule. Interested to see what others do.

[Lee Schierer]

The oft quoted (but not necessarily accurate) rule of thumb is a year per inch so if your cherry is now 1" thick you would need to wait approximately 3 months depending upon the MC in the area where it is now being stored. Ohio like PA currently has pretty warm temperatures and high humidity.

[John TenEyck]

IMO, it depends upon how stable the RH is in your shop. My shop drifts slowly from about 35% in the Winter to a dehumidifier limited 60% in the Summer. Because the RH changes slowly the MC is essentially the same throughout the lumber I have in long term storage. When I resaw a piece of 8/4 the MC will be the same on the cut faces as the outside, and there is little/no movement unless the wood has some other form of stress in it. If the resawn pieces are flat I go ahead and use them right away; no acclimation needed. If they aren't flat I set them aside, stickered or just leaning against the wall, overnight and try working with them the next day or whenever I get to them. Sometimes I'm able to mill it and it's OK. Other times, it will continue to move no matter what, like when ripping a stile off a wider board. Those pieces generally get relegated to really short pieces in non critical places, never in a door frame, or go to the woodstove.

If the RH in your shop varies more directly with the weather, like it will in a garage shop with no climate control, and you live somewhere where the weather changes frequently, like I do in the NE, then I think you need to be more cautious and sticker or edge stack your resawn boards for a day or two before milling to final dimensions. A RH meter hanging on the wall and a moisture meter would both be helpful in deciding how best to handle your lumber.

John

[Doug Dawson]

I have just resawn some 8/4 cherry for a end table. The cherry has been in my shop for over five years. After I resawed it I stickered and put some weight on top.

My question is how long should I leave it this way before surfacing to final dimensions? I don't want any surprises later with it twisting. Thanks

If you have a moisture meter (and you should,) til the moisture content is the same on both faces of the wood. This can take a while, depending on the environment. I have thick stickers, a drying room, and a lot of patience.

[Mark Hennebury]

My rule of thumb is to observe, analyze and act accordingly.

If it cupped when sawn, either way, middle into the blade of middle away from the blade, it is not at equilibrium.
If the middle cupped towards the sawblade then the outside is dryer than the inside.
If it cupped with the middle away from the saw then the inside is dryer than the outside.
If it stayed straight, then your wood is at equilibrium and stressfree.
Based on the time your wood has been in your shop you should have no problems using it.

If your wood had just arrived at your shop that would be a different matter, it may not be at equilibrium with your shop, and would adjust to the new environment.
So if you resawed the newly arrived wood, and it stayed straight, you can tell that it is equilibrium within the wood itself. if you then observe over the next few days you can tell if it is at equilibrium with the shop. lay a piece of the wood on your bench for a day or two and watch it, if it cups then it is not at equilibrium with your shop.
depending on the way it cups will tell you if the wood is taking on or losing moisture, and would then need to be stickered for a while.
Laying the piece on the bench will allow moisture exchange to take place through the side that is exposed and will show up as cupping if there is any moisture differential between the wood and the shop.

Having said that i usually rough dress over size, and sticker for a few days before final dressing anyway.

[Matt Day]

I think the OP is asking about resawn stock that has already been dried, so we’re not talking about wood fresh off the sawmill.

[Doug Dawson]

I think the OP is asking about resawn stock that has already been dried, so we’re not talking about wood fresh off the sawmill.

It depends on what the meaning of "I have just resawn" is. :^)

[Matthew Curtis]

This is Kiln dried cherry that has been in the shop for 5+ years.

The meaning of just resawn is:. I took 8/4 cherry to my bandsaw and cut it into 2 pieces about 1" thick, Friday evening.

[Bryan Lisowski]

I would let it sit a week, maybe take the weight off in a couple days, then if it stays flat and true over those final days, you are good to go.

[Jim Becker]

I will add that you'll really want to remove a little off the un-sawn side, too, and then see how it goes for a few days to a week. Every board is different...

[Robert Engel]

Lots depends on your shop climate and ambient humidity levels.

I would leave in stickers for a week, then lightly joint and plane, re-sticker for another week,.

If its flat, proceed with milling, probably in 2 more stages.

BTW, I use clamps instead of weights. I did this on a project that had 3/8" solid panel drawer bottoms and I think it works better.

[John TenEyck]

What do you folks think commercial shops do?

John

[Mike Cutler]

I personally tend to let it sit clamped, or banded, for a few days to a week.
I will generally re-saw, it and then run it through the jointer/planer on both sides. Not finished thickness, but close.

For clarification, I am referring to kiln dried wood.

[Mark Hennebury]

What do you folks think commercial shops do?

John

Many of them ignore or don't understand moisture content and wood structure, go ahead and make stuff and then ask why its warping and splitting.

[John TenEyck]

Many of them ignore or don't understand moisture content and wood structure, go ahead and make stuff and then ask why its warping and splitting.

You might be right about some shops, but not many survive very long doing that. And if you look at the larger ones, the lumber they buy is spec'd to be at a certain MC, and gets rejected if it's not. Once it's approved, they use it as needed. Anything that twists, etc. gets sorted out and used for something else. The vast majority keeps moving through the process.

Caution is OK but there's a point where it adds nothing to the project but time.

John

[Mark Hennebury]

You might be right about some shops, but not many survive very long doing that. And if you look at the larger ones, the lumber they buy is spec'd to be at a certain MC, and gets rejected if it's not. Once it's approved, they use it as needed. Anything that twists, etc. gets sorted out and used for something else. The vast majority keeps moving through the process.

Caution is OK but there's a point where it adds nothing to the project but time.

John

Hi John,
I understand that the better shops pay attention to moisture content, and agree that with you that they spec and check if they want to avoid problems.
I have seen many question even in large shops, why are the panels warping and cracking etc, and the answer is always the same did you check the moisture content of all the pieces prior to glue-up etc.. Always moisture related.
As for my explanation to answer the OP's question, it was for a no-tech hobby-shop approach to knowing what you are dealing with. No equipment or specs necessary, just observation and understanding.

Mark

[Matthew Curtis]

So basically from a day to a few weeks.

[Jim Morgan]

It depends on how stable RH is in your shop. If it's stable, after five years stored in your shop, MC should be uniform throughout the thickness of the cherry, so a few days of additional stickering is fine (not a bad idea to plane a little off of the original exterior faces, JIC). If the RH has gone through some wide swings recently, sticker the resawn pieces longer, until the MC has equalized. You haven't told us whether you control humidity in your shop.

On the other hand, if resawing released significant internal tensions, then you will have additional work to do.

[johnny means]

Many of them ignore or don't understand moisture content and wood structure, go ahead and make stuff and then ask why its warping and splitting.

Or know what they're doing and avoid putting themselves in a situation where they have to sit an watch wood dry.

[Doug Dawson]

Hi John,
I understand that the better shops pay attention to moisture content, and agree that with you that they spec and check if they want to avoid problems.
I have seen many question even in large shops, why are the panels warping and cracking etc, and the answer is always the same did you check the moisture content of all the pieces prior to glue-up etc.. Always moisture related.
As for my explanation to answer the OP's question, it was for a no-tech hobby-shop approach to knowing what you are dealing with. No equipment or specs necessary, just observation and understanding.


I read your earlier post, and it was good. I would add, though, that resawn wood may deform due to uneven moisture content, or it may deform due to released tension. Those are different causes, and it helps to differentiate them by actually measuring the moisture content with a meter, when you're deciding how to proceed.

BTW, ob "watching" the wood reach a moisture equilibrium, this is a matter of time management. You can either age your wine in the bottle, or you can drink it straight out of the box.