It is not enough to use perfectly dry lumber at 6-8 percent when producing cabinets and furniture, according to AWFS fair exhibitor Lignomat USA Ltd., a supplier of pin and pin-less moisture meters, kiln controls and more.
“Lumber always interacts with the surrounding air,” the company writes. “A product manufactured with dry lumber at 6-8 percent is not staying within that perfect range, if the surrounding relative humidity is not appropriate. A glance at the EMC chart states, that the relative humidity has to be kept between 30-50 percent at a temperature around 70 degrees for wood to stay within 6-8 percent moisture content.
“In case the relative humidity falls out of this ‘comfort zone,' wood starts picking up or loosing moisture. Changes in moisture content are often accompanied by shrinking, warping and cupping; followed by customer’s complaints.
“Using a combo meter, which offers pin-less, pin and RH measuring technology, will cover all applications to measure moisture and humidity. Thus, moisture problems can be avoided and when they occur they can be tracked.
“The first step is to make sure, the wood used in production is well seasoned and dried from surface to core. Handheld moisture meters are used to check for the correct moisture content when the lumber comes out of the dry kiln and before it is used in production. Pin and pin-less meters are available. Pin-less meters usually measure 3/4” deep and need a flat surface. They work great on flat boards up to 6/4” thick. For thorough testing of boards over 6/4” thick, or round and irregular shaped pieces, pin meters are recommended. The thicker the wood, the more important are core measurements. On the other hand, pin-less meters allow for checking large number of boards quickly.
“Next, the relative humidity needs to stay within the recommended 30-50 percent. This includes any storage area, the place of production or workshop, the warehouse, during transportation and acclimation at the job site and last after the place is occupied.”
For more, visit AWFS booth No. 4135 and www.lignomat.com.