Moisture content of walnut -- and measuring it

A woodworker seeks information about acceptable moisture contents for walnut used in furniture, and wonders what makes moisture meters tick. 1998.

by Professor Gene Wengert

I recently harvested and milled around 700 bd. ft. of walnut lumber. The boards were cut to 1 1/8" thick with various widths and lengths. All of the lumber was stickered and placed in an old corn crib to air dry. The lumber has been in the corn crib for one month. What would the total drying time be before it can be used for interior furniture?

Also, is it necessary to sticker the walnut with walnut stickers?

I was also wondering if it was possible to construct a moisture meter from available electronic components.

Is moisture a measure of conductivity or resistance?

The crib will never achieve a MC under 12% MC. For furniture you need 6 to 7% MC.

No. Any strong, dry species will do.

Just about anything is possible, but I do not believe it is at all practical. Further, you might have trouble calibrating the meter.

There are resistance meters and there are dielectric meters--that is, the meters measure resistance or the dielectric and then relate the value to MC. But when you measure resistance, conductivity is [1/resistance].

Professor Gene Wengert is Extension Specialist in Wood Processing at the Department of Forestry, University of Wisconsin-Madison.

Click on Wood Doctor Archives to peruse past answers.

If you would like to obtain a copy of "The Wood Doctor's Rx", visit the Wood Education and Resource Center Web site for more information.