oak problems

[Jack Wood]

I recently got some 2"x6" oak boards that were at least 10 years old. I resawed one of them down in to 1/2 and 3/8ths pieces to make some small boxes with and now the lid on the box I made is warping:( Is this normal with oak? I haven't had this problem with other types of wood I've used. So now I have a lot of oak boards that I'm reluctant to use because of the warp potential, how do I prevent them from doing this?:confused:

[Donnie Raines]

Could be any number of things: the relative mositure content of the lumber could have been high...even at that age. The manner in which the tree grew....could have retained a large qty of tension(though this would have been more noticeable when you first cut the boards). The boards could be cut very near the pith(center) of log.....this will have more of an arch shape growth ring pattern to it....and the board will move with the growth rings(thus, thats why qrt sawn boards are more stable). Look at the end of the boards and see if the growth rings make an arch(half moon). If so.....this is likely the issue.

[Tom Saurer]

They were probably under some tension and when they were cut into smaller lengths they warped. I've had it happen with oak and ash.

[Scott Banbury]

The wood likely had a moistue gradient in it (wetter inside than out or other awy around).

I'd sticker the material and give it a chance to even out--it may go flat once it does.

[lou sansone]

I work with a fair amount of thin wood and one of the things I have found when resawing stock is that there is a gradient often in the wood. once resawn it will tend to move around to get rid of that gradient. I have experimented with a number of ways to minimize this. I have found that after sawing if I sort of mix up the wood and then put it in a plastic bag for a few days with weight on the top that they tend to behave themselves. I go back every so often and mix them up again and then put weight back on top. I don't really close up the bag, but leave it open or sometimes just laying on top of the pile. That has seemed to work for me. When I say thin stock I mean 1/8 to 3/8 thick stuff.


lou

[Lee Schierer]

Most like the problem was due to moisture content of the wood. Wood that is dried outdoors, even under cover will only reach 12-20% MC. Wood dried indoors in a dry shed might do better than that. Your shop is a dry place and when you resawed the 2" wood you exposed inner material that most like had a different moisture content than the outside surface wood. The stabilized the exposed wood to tthe environment and the MC changed. This causes the warpage.

I once worked with some boards that had been air dried for over 15 years. I assumed that since it was old it would be dry. Every piece I made from that wood changed size, warped, twisted or cupped when I planed it to thickness. That's when I bought myself a moisture meter. It was sure cheaper than reworking the project. Now any wood I don't know where its been and what its seen gets checked by the meter after the first cut is made that exposes interior wood.

When planing rough lumber it is important to take off an equal amount from each surface to keep the wood stable.

[Ralph Barhorst]

I once worked with some boards that had been air dried for over 15 years. I assumed that since it was old it would be dry. Every piece I made from that wood changed size, warped, twisted or cupped when I planed it to thickness. That's when I bought myself a moisture meter. It was sure cheaper than reworking the project. Now any wood I don't know where its been and what its seen gets checked by the meter after the first cut is made that exposes interior wood.


Lee - What do you do to the wood if it is not to your liking? Do you have it kiln dried? I have had this problem with a lot of 8/4 wood that I bought. This happens when I resaw it. It is OK if I just plain it on both sides down to the thickness that I need. It bows in the direction that would indicate that the outside is wetter than the inside.

[Tom Saurer]

Wood will equalize to whatever the moisture content is around it. Air Dryed or Kiln Dryed wood will eventually equalize to the same moisture content. Kiln drying is simply a faster way to get the moisture out.

Wood that has been air dryed for 15 years should have been dry enough. It probably warped because of tension created when it dryed.

[Ian Abraham]

Wood that has been air dryed for 15 years should have been dry enough. It probably warped because of tension created when it dryed.


Unless it's been sitting in a barn for that 15 years... it will be 'dry' and stable... at 10-15% moisture. Bring that inside and it will dry further and maybe warp. Of course tension in the wood can cause this too.
Either checking with a moisture meter or letting the resawn boards sit with weights on them for a couple of weeks will help if it's moisture related. If it just came from a crooked tree.. not much you can do :o

Cheers

Ian

[Jack Wood]

Thanks for the info! I guess I jumped the gun when I made the box right after I cut the oak to size:( And Lee I believe I may have not paid much attention to how many times each side got planed, tried to keep it even but went more for which side looked the worse:rolleyes: So I need to let it sit for awhile after sawing, keep the planing equal and look at the growth rings, man and I thought that nailing two sticks together was so going to be so simple!:p

[Tim Sproul]

"the lid on the box I made is warping"


I'll take a little different interpretation.

If uneven moisture content, the resawn boards typically warp right off the saw. I'd guess you may have had a decent swing in humidity and the lid was closed.....did a crown form on the lid or did the lid turn more like a cup? And was a recent swing in humidity to higher humidity - would correlate well with the lid crowning or did the humidity recently drop - could correlate well with the lid cupping.

I'd also hazard the lid hasn't had any finish applied or it is only an oil finish or similar finish that doesn't inhibit moisture flow much.



If you resaw boards into relatively thin boards and want to sticker them, it is best to clamp the boards between the stickers or heavily weight the stickers at the top. Let them acclimate for a time - much dependent on the thickness of the boards AND how stable the humidity has been.

[Lee Schierer]

Lee - What do you do to the wood if it is not to your liking? Do you have it kiln dried? I have had this problem with a lot of 8/4 wood that I bought. This happens when I resaw it. It is OK if I just plain it on both sides down to the thickness that I need. It bows in the direction that would indicate that the outside is wetter than the inside.

Any more, I buy all my lumber milled on four sides from a local source. They do excellent work kiln drying their lumber and even though it is more costly than rough lumber I can buy here in PA, it is knot free, check free and I can't remember the last time I had a piece warp or twist after sawing, resawing or planing it.

The boards I wrote about before had been stored in a shed with an earth floor. Even though the boards were elevated and covered by the roof, the moistuyre content was still pretty high. A piece that I checked after getting the moisture meter read 12%, but wood that had been in my shop read about 8% with the same meter.

[lou sansone]

When planing rough lumber it is important to take off an equal amount from each surface to keep the wood stable.[/QUOTE]

Hi lee
I agree with you in general, but when you have resawed a piece of wood in half. I don't see that this still holds true due to the enevitable moisture gradient. What do you think?
lou