By Gene Wengert, wooddoc@uwalumni.com
Spent time reducing the highest moisture content value.
Q. Good news for us: Our business has increased. So, we need to get lumber through our kilns a little bit faster. Do you have an advanced kiln schedule or other help?
A. When drying lumber, it is the wettest piece of lumber that must be dried to a low enough moisture content in order for us to turn off the kiln. As there are no advanced schedules, other than the “normal” schedules in the book, and if you need to increase kiln output (shorten drying time), you can do it by reducing the moisture content of the wettest incoming lumber. Ask yourself why is that wettest piece so wet while all the other pieces are drier, oftentimes considerably drier. Spend time in reducing this high MC value. Perhaps it is high because the bottom pack in air drying does not get enough air flow; if so, after 60 days, move the bottom bundles to the top and top bundles to the bottom. The cost is $3 per MBF, but if you can come into the kiln 2 percent MC drier, you will save about 1 day, save energy and not have to make an investment in an additional kiln. A day savings in the kiln is easily worth $20 per MBF.
Note that you can also get lower MCs by air drying or predrying longer times, but that is often very expensive. If you are unable to figure out how to achieve lower MCs and optimize your drying, there are drying consultants like myself that can offer on-site help.
Gene Wengert, "The Wood Doctor," has been training people in efficient use of wood for 35 years. He is extension specialist emeritus at the University of Wisconsin-Madison.
Updated: Oct 12, 2012