Wood movement problems

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Forum topic by Purrmaster posted 11-28-2012 08:03 AM 1967 views 0 times favorited 21 replies Add to Favorites Watch
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915 posts in 2297 days

11-28-2012 08:03 AM

So I’ve got a problem. I bought an ash board from Rockler last week. When I got it in the store it was nice and straight. A few days in my shop (a drafty, unheated barn with a dirt floor) the board cupped quite a bit. The board isn’t wide enough for my project so I have to edge join two pieces to make a wider piece. But of course the warp in the board means the glue joint isn’t straight.

The wood is only 1/2 inch thick. If I run it over the jointer I’m going to lose a lot of wood and I’ll be left with something the thickness of a toothpick.

I tried sticking the pieces in a vise for a day to see if that would help and it didn’t. This is basically happening with almost every board I bring into the shop.

I realize the environmental conditions in my shop are terrible. But I can’t do anything about that. It’s too large and drafty to heat or dehumidify. I’d be trying to heat and dehumidify the outdoors.

I’ve run a few pine boards over the jointer that were warped. I put those things into a vise for a month. It didn’t straighten them at all. After removing about half the wood it was (more or less) straight. But it wasted a lot of material. And, of course, in a day the newly flattened board warped again. Plus, lumber is expensive and half of what I buy turns into jointer shavings.

Is there anything I can do to:

1.) Prevent the warping when I bring a board in.

2.) Straighten the board out without losing so much material.

I suspect the answer to these questions is: No, not with my current location and equipment. But I figured it couldn’t hurt to ask for ideas.

21 replies so far

View David Craig's profile

David Craig

2137 posts in 3313 days

#1 posted 11-28-2012 08:12 AM

How are you storing the wood? On edge? Or laying it face down on a surface?

-- There is little that is simple when it comes to making a simple box.

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915 posts in 2297 days

#2 posted 11-28-2012 09:13 AM

I’m storing it standing up. Same as I see it at the woodworking stores.

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13640 posts in 3545 days

#3 posted 11-28-2012 09:26 AM

nakashima made himself a kind of coat rack
with longer arms sticking out
and stored the wood on edge standing up
that way both sides weathered and dried equally
and as on edge
they didn’t relax
and bow back to the wall
stacking then eother flat or as you have them
(if there are more than one)
only exposes the outer face
and edges
the rest talk to each other
and share moisture
so don’t dry the same

might give it a try
see how it goes

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

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David Craig

2137 posts in 3313 days

#4 posted 11-28-2012 09:34 AM

As David already eloquently pointed out, your board is cupping because of unequal moisture disipation in the wood. Store the wood opposite of how you got the cup in the first place. It should start moving in the opposite direction. When you store your wood in the future, try to position your wood so it receives even air flow. The stresses won’t release in a one sided manner that way. If you plane any wood, plane both sides. If you give both faces even treatment, you should encounter less cupping issues.

-- There is little that is simple when it comes to making a simple box.

View paratrooper34's profile


915 posts in 3156 days

#5 posted 11-28-2012 10:15 AM

When I bring wood into my basement shop, which is dry during the winter and somewhat humid in the summer (dehumidifiers in use), I sticker them. I have stickers of equal size and some red oak chunks for the top board. Have yet to have a problem with warpage. The wood stays like that until I am ready to use it. That might be a good thing for you to do to give the wood a chance to stabilize straight.

Good Luck.

-- Mike

View Brandon's profile


4152 posts in 3156 days

#6 posted 11-28-2012 12:17 PM

Also, have you looked into purchasing hardwood from other locations? When I first started buying wood, I purchased lumber from Rockler. Then when I decided to check prices at some hardwood dealers in the area, I realized that I was paying close to double the price of wood. It’s not too bad if you need one piece of wood and it’s convenient, but if you’re buying a lot of wood, I would avoid Rockler. Good luck on your work!

-- "hold fast to that which is good"

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915 posts in 2297 days

#7 posted 11-29-2012 05:30 AM

I can’t find many lumber yards in my area (Portland Metro area of Oregon) that sell hardwoods. I’ve noticed the woodworking stores are rather spendy.

As for building a coat rack… I’m not entirely sure what you’re talking about.

View DMC1903's profile


285 posts in 2531 days

#8 posted 11-29-2012 05:36 AM

Here is a link to a Hardwood supplier in PDX, a buddy of mine gets his Hardwood there.

Hope is helps, if not do a google search for suppliers.

View David Craig's profile

David Craig

2137 posts in 3313 days

#9 posted 11-29-2012 05:41 AM

Purrmaster patron (David), is talking about something that insures equal air movement around your boards when you store them before use. Kind of looks like a coat rack but has arms to hold boards out at lenth when stood up vertically. When you store boards in your work area, the cupping will reduce if you don’t stack them in a way in which air can’t get to both faces equally.

-- There is little that is simple when it comes to making a simple box.

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915 posts in 2297 days

#10 posted 11-29-2012 09:18 AM

Does anyone have any pictures of this device? I could try to build one.

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David Craig

2137 posts in 3313 days

#11 posted 11-29-2012 09:40 AM

I tried looking up pics of George Nakashima’s shop and do not see the device mentioned. Here is a picture of a wood rack, complete with stickers, that should give you an idea on how wood is stacked to allow air movement on both sides.

Have you tried the suggestion of switching sides for drying to even back out the cup?

-- There is little that is simple when it comes to making a simple box.

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915 posts in 2297 days

#12 posted 11-29-2012 12:01 PM

Thank you. Yes, I did change the board around. The cup is still in the same place and, I think, getting worse. It’s happened to the hickory board too.

I eventually ended up jointing the cupped ash board. And what I ended up with was exactly what I was afraid of: A very thin board that still wasn’t perfectly straight. I had to remove so much material to get past the cupping that the board was basically toast. A few board feet of ash down the drain.

This wood movement has been a huge problem for me. It wasn’t as bad during the summer, though it did happen. But it’s cold now and the humidity is always high.

I’ll see if I have enough scrap wood to make a sticker pile. And if I have enough floor space for a sticker pile.

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Don W

19018 posts in 2772 days

#13 posted 11-29-2012 12:21 PM

I’d lay the cupped board on the dirt floor, with the cup down. The moister from the floor may help bring it back.

I’d also try to store the lumber as far from the floor as you can. If you plan to do a stack like David suggest, add a layer of plastic under, but not directly under the stack.

The problem goes beyond storing your lumber. Buy an inexpensive moister meter (lowes has them for about $30) and see what the content of the board is to start with, and what your shop is. It sounds like the moisture content in your shop is high, but you should know that for sure.

My shop has a concrete floor and a tin roof. If I store lumber on the first floor the average content is 11-12%. If I move it to the attic it drops to about 9%. Do some testing like that. See were the best spot in your shop is (if there is one)

The point is, you’ll need to plan for drastic wood movement after you’ve built your project and move it to your house (or anybodies house). Its one thing to have a piece of lumber ruined by movement, its another to have a project ruined by it.

-- - Collecting is an investment in the past, and the future.

View JAAune's profile


1853 posts in 2521 days

#14 posted 11-30-2012 04:15 AM

Keeping newly purchased wood from moving after bringing it to the shop will never be 100% successful. For this reason, I prefer to buy either in the rough or partially milled to “hit or miss” thickness. Basically, since the wood seldom stay flat, I’d rather do my own flattening right before starting the project.

If possible, buy wood from a dedicated supplier of furniture grade hardwoods. That will solve half your problems and save some money too.

-- See my work at and

View longgone's profile


5688 posts in 3513 days

#15 posted 11-30-2012 04:50 AM

I have a 12×20 non-insulated shed with a metal roof especially for storing my lumber. A good while back I bought a bunch of sinker cypress that was freshly milled after being underwater in the swamp for about 150 years. It had a moisture content of about 60%. I stickered it and layed it flat with a dehimidifier running. It now…about 8 months later has a moisture content around 6 to 7% and is flat and straight. A couple of the shorter boards that I stored vertically had warping.

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