Question
I'm had a big black walnut milled last summer and then stored it in a grain bin. My new Christmas moisture meter said that it was dry, which I found hard to believe. I did an oven test and came up with 13.5% moisture. Should I dead stack it, or leave it alone until it gets somewhat dryer?
Forum Responses
(Sawing and Drying Forum)
From contributor S:
Leave it alone, unless you really need the space.
The argument over using air dried versus kiln dried lumber in modern woodworking has been raging for years and will continue. But do you really want to put a lot of work into a furniture project and then have problems due to moisture content of the wood?
Build a small solar lumber kiln and get it down to 6-8%. Just remember once the lumber is kiln dried, you need a dry place to store it or it will begin picking up moisture again.
I've tried to read everything I can about drying lumber and it seems that an awful lot of people want me to have it sit for a year and then put it in a kiln. Which I don't quite understand (and believe me I'm not trying to be snotty here, I just can't figure this out). If I put the stuff in a kiln and theoretically dry it to 0%, won't it revert back up to whatever the average humidity is in my climate? Likewise if I only air dry it, won't it eventually get down to that point? What am I missing?
I do not like drying wood in a shop as often the shop is not as dry as a home. Further, it can provide entry for insects. Also, the moisture from the lumber can raise the humidity possibly enough to create some rust issues or mold in the shop.
You can store as long as you like. Your only risk in the bin is that there could be an insect in the wood and so you could get a bit of damage. However, if you can get the wood up to 130 F, that will kill any insects.
The average outside RH in almost all of the US is 65% RH, which results in 12% MC in lumber. Hence the outside conditions are called 12% EMC (equilibrium MC). With the heat in your bin, you would be lowering the RH, so you should see a lower MC value, perhaps 10% or lower. Therefore, I wonder if your MC measurements are correct. Just a thought.
