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Pin Oak: Drying, Checking, and Bacterial Odors
I just got my first mill and I have a couple questions. First, does anyone have any experience with pin oak? I have heard that pin oak is not a very good wood to saw. I'm looking to build a rustic shed and I am curious if pin oak will be ok to use. Also, can you use regular paint to apply to the ends of cut boards in order to discourage checking or do you need something special? Question
From contributor S: Pin oak has more knots than northern red oak. It should be fine for your shed though. From Gene Wengert, forum technical advisor: Pin oak is fine. End coating to prevent checking must slow the drying rate of the ends of the lumber. Some paint will do that; some will not. Commercial coatings (such as Anchorseal) will work all the time to prevent drying checks. Oak is especially tough (high risk of end checks) due to its high shrinkage. Most other species shrink less, so have less risk. In fact, yellow-poplar, soft maple, and a few others do not need a coating for 4/4 through 6/4. Thicker stock of valuable woods should always use a commercial coating as the risk of loss is so great, financially.
From the original questioner: Do I need to dry the lumber any before I begin building or can I use it fairly green? From contributor S: The oak boards will be easier to nail when green, but then gaps may appear in the siding boards when the lumber dries. From contributor T: Pin oak will be structurally fine. I don't know if it is a New Jersey thing, but pin oak from here smells the worst. From Gene Wengert, forum technical advisor: The odor is likely bacterial wetwood. This bacterial infection is site related and has been discussed in more detail. It is found in many species, especially in wet sites. From the original questioner: Part of the tree we just sawed was infected and it smelled like sewage when we first cut into it but the heartwood was fine. From Gene Wengert, forum technical advisor: That is indeed a bacterially infected tree. It is very difficult to dry that wood (which is probably only the bottom couple of feet of the bottom log) without severe defect. If you do find honeycomb, end checking, etc., it is not your fault or incorrect drying practices. Bacterial infections are found in all oaks, especially older trees in wet sites. The bacteria do not jump from board to board or log to log, however. Pin oak can produce excellent lumber if not infected.
From the original questioner: Thanks for the help. If I cut off the edges that look infected will the heart wood be ok? Other than the outside 2-4 inches everything looks good. From Gene Wengert, forum technical advisor: Heartwood can be infected with the bacteria. I would not cut it off before drying. Note that the smell can return after drying especially if the humidity is high.
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