Analyzing Moisture In Wood and Wood Products

Available in a variety of styles, including pin and pinless, moisture meters enable wood products manufacturers to accurately measure the moisture content throughout all phases of the manufacturing process. Photo courtesy of Lignomat USA.

Moisture meters, essential tools for quality control in a woodshop, measure the amount of water in lumber. This lets you determine if it is at a suitable content level for the intended use. This is critical. If moisture content runs too high or low, it can lead to shrinkage, cupping, crowning, buckling or cracking, among other problems.

While optimal moisture content will vary by species and application, as a general rule for fine furniture and other indoor products, 6 to 8 percent is a good target.

The two most common types of moisture meters are pin and pinless. Pin-type moisture meters, also known as resistance meters, operate using the principal of electrical resistance. By driving two or more pins into the wood, a direct current travels from one pin to the other, while measuring the resistance to that current. As you might expect, moist wood conducts more current than dry. The meter then correlates the amount of resistance to the wood’s moisture content.

Pinless meters, also known as electromagnetic wave technology meters, measure the moisture content without piercing the wood. These meters instead send electrical waves through a sensor that is pressed against the wood, creating an electromagnetic field within the wood. The electromagnetic field measures the capacity of wood to store energy, the amount of power the wood absorbs from the field or the wood’s resistance to the field. The pinless meter then translates all this information to percent moisture content.

What follows are some of the moisture meter products available in the marketplace for custom woodworking manufacturers and contractors. For a complete list of suppliers of pin and pinless hand-held meters, as well as for larger moisture measure systems, check out the Plant Production chapter at RedBookOnline.com.

Lignomat USA’s pinless moisture meter, the Ligno Scanner SDM, is designed for measuring moisture without damaging the surface. It enables wood cabinet and furniture makers to choose the measuring depth; the feature is suitable when boards thinner than 3/4 in. are used, or when boards are not dried evenly, and the difference between core and surface moisture can be measured by toggling between ¼ in. and 3/4 in. deep. (503) 257-8957, Lignomat.com