Q: We just planed some red oak lumber and we noticed a lot of small surface cracks showing up immediately and even more later on. Help!
A: If red oak is dried too quickly when the moisture content is more than 50 percent MC, the stresses that develop will crack the wood on the surface. Such cracks are called surface checks. It is common that these checks will close (but not heal) as drying proceeds. But the checks are open under the surface.
When you plane the lumber, you remove the closed part of the check, and expose the deeper portion that is open. So, your lumber has deep surface checks. Apparently, the lumber is a little wetter than the air, so as the surface dries and shrinks, some of the closed checks are reopening.
Have something to say? Share your thoughts with us in the comments below.