Several months ago I bought some air dried red oak. I had never bought from that mill so it was something of a quality check for future purchases. Overall the lumber has been good but I'm not real sure how well it was dried. The owner claimed it was cut ~4 years ago and had been stacked and drying outside ever since then.
The only real problem I've encountered so far are these cracks that appear along the entire face of some of the boards:
(https://forestryforum.com/gallery/albums/userpics/16815/1969/Cracks.jpg)
These are probably an average size of the cracks but some are up to 3x as long, making them very noticeable. Some boards have 'em, some don't. Were they there when I bought the lumber? I really can't say, they could have been but they also could have developed since bringing them inside.
Any ideas or opinions of what the problem is from the drying experts?
Clark
Oak can surface check like that if it's dried too quickly. That can be an issue even air drying in dry / windy / hot weather. The outside of the board dries (and shrinks) quickly and so develops those little splits. They will usually plane out. Other than that the wood is probably OK, that problem occurs in the first month or so of drying. After that, the centre of the board is also starting to dry out and shrink to match, but the damage is done.
Ian
When sawing oak, those cracks can easily begin just by leaving the surfaces of the green oak exposed in the sun while going in for lunch break, or doing other chores.
Sometimes jacket boards are pulled off the sawmill while sawing for a cant, and the boards are just left exposed until getting around to edging or just getting around to stacking on stickers.
That short time exposed to the sun or warm, dry wind will cause enough surface drying to have failure. This damage later shows up as the small cracks that are exposed in the pics.
Keeping the green boards/flitches protected from fast drying, including the fast drying while in an air dry stack is important with oak.
we see it all the time but, once its planed most all the cracks are removed.i wouldn't leave any wood out in the weather for more than a year.
Thanks for the replies, I think I'll try this mill again. Probably pick through things more thoroughly though.
Clark
Clark,
Were the cracks deep enough to remain after you finish planed them? How thick were the roughsawn boards? Were these cracks on both faces?
Metalspinner,
That's a good question. I think some of them are and will remain like you see above. Had I taken another pass with the planer I think I would have gotten them out. As it stands now I'm fine with those. You really have to look for them to see them.
Some of the other boards have developed bigger cracks which I think are more the result of improper drying. Adding to that I took them into a shop that is heated...when you need it to be. So this entire winter those boards were heated and cooled several dozen times in fairly dry air. I don't know if that has exacerbated this problem or not.
I'll probably go back and pick out some 1/4 sawn stuff this spring and see how it does in the summer humidity and heat. I have a feeling that it won't be such an issue and if I can finish and seal any new projects during the summer then I like to think that the wood will slowly stabilize and not develop deep cracks. Let me know if those expectations are high as a kite!
Clark
As Ianab said, those surface checks developed when the wood was above 40% MC. They are not going to grow now but they can open/close when the wood changes MC.
Honeycomb, on the other hand, can be very ugly. A single pass through a planer might expose small cracks like you see. A second pass intended to clean up the board can make the cracks worse. The deeper you go, the wider they get.