Walnut Slabs Moisture Content
I found some Walnut that was at a good price. The moisture content is between 10% and 12%. The slabs were cut from 2 year dried logs. Do I need to look for a kiln to dry this stuff the rest of the way or can I let this air dry? (I’m assuming I really should let the lumber get down between 6% and 8%.)
I have plenty of space to spare in a barn, so space is no concern for me since I can keep it out of the elements. I’m just not sure if this requires any kiln drying if I am going to use the stuff to build a table or other furniture.
Air drying of stacked and stickered wood in a barn will bring wood down to an equilibrium moisture content (EMC), depending on the relative humidity (RH) of the atmosphere around it. There are charts available showing this relationship. Check Wikipedia's article on EMC vs. RH.
I have wood in a similar situation. Since our weather keeps the humidity in the 90% range, my wood won't go below 15 to 18% so further drying is needed. My choices are to rough mill the stock, leaving room for shrinkage, etc. and then bring it in to the shop for "a while" to dry further, or place it into a small, insulated dry box that's heated with a 100 watt bulb.
In any case, air-dried black walnut is much prettier than what comes out of commercial kilns which steam the wood and kill the color variations.
Yes, you will need to do something to get it down to 8%.
It is probably in a state of equilibration already, which as the previous poster explained quite accurately, is dependent on your climate.
In my climate, fully acclimated lumber runs 12-18%. For final drying to 8% I move lumber into a climate controlled room in my shop with a dehumidfier. I like the "low and slow" approach to drying wood.
Thanks very much. That’s all good information / advice to have. One thing I had considered (but am not sure if it is a useful undertaking) was to build a solar kiln. I had found some plans published by Virginia Tech. But I’m not sure if that is necessary (at least with the lumber in question above dried to already 10-12 percent).
The summer 1977 issue of FWW also has a plan for a solar kiln.
Whether to build a kiln hinges on a few different crieria: Space, expense, how eager you are for your wood to be dry, how good the supply of green material going forward, whether you can share or rent out space in the kiln with others and how much local lumber you'll be drying over the years.
Oh yeah, and your local climate.
Definitely have the space. Probably more pertinent would be what I am planning to dry and if I’d be picking up green lumber. Sounds like for now, it might be overkill and using a dehumidifier in a climate controlled spot might be fine.
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