Overview
Why Test for Moisture Content in Wood?
Knowing wood’s moisture content is crucial to prevent costly wood project failures or customer complaints. Why?
As part of its natural beauty and appeal, wood is a hygroscopic material, meaning that it will continuously lose or gain moisture from its environment. The same cellular structure that lets a living tree absorb moisture up its length also means that it can retain or release water after it has been sawn, dried and finished.
That process can cause problems in your woodworking projects. Swelling, checks, cupping, gaps at joins, or even finish failures can all be related to a moisture content that is too high or too low compared to its environment. No one wants their time and resource investments to result in a warped chair, a buckling wood floor or a moldy carpet.
The good news is that measuring the moisture content (MC) of wood is a simple and cost-effective way to minimize those costly failures. Companies like Wagner, Delmhorst, Protimeter, Tramex or Lignomat make a variety of wood moisture meters (also called moisture detectors) with features to help all levels of wood workers from the hobbyist to the professional. Most are handheld meters with digital displays and can be found in pin- or pinless-type moisture detectors. (For a comparison of the technology of the two types of moisture testers, see Moisture Detector Technology.) Wood moisture meters can be calibrated for various wood species and measure moisture below the wood surface for greater accuracy.
The right wood moisture meter is a vital tool for the woodworker at any level.
Technology
The two main styles of wood moisture detectors (or moisture meters) are commonly known as “pin” meters and “pinless” meters.
Pin Meters
Pin meters get their name from the fact that each moisture detector has two or more pins that must be pushed into the wood in order to take a reading. A small current travels from one pin through the wood into another pin. The drier the wood is, the less current is able to pass through. Pin meters read how much resistance there is to the current and correlate that resistance to the wood moisture content.
“Pinless” Meters
Pinless moisture meters do not have to pierce the wood to take a reading. Instead, they send out electrical waves to create an electromagnetic field (EMF) to a specified depth. The meters translate the impedance of this field to determine the moisture content of the wood.
Pros and Cons
The obvious drawback to a pin meter is the damage the pins cause to the surface of the wood. Some models are also rather difficult to use because cables are used to transmit the charge and can be easily tangled or twisted, and such movements may also affect readings. Most models have the digital display upside down when the pins are inserted.
On the plus side, the using insulated pins with pin meters means that they are rarely influenced by surface moisture.
Handheld pinless meters are typically simpler to operate, and as might be expected, do not damage the wood surface. But they can be much more susceptible to surface moisture – just wiping the surface with a damp cloth can make the readings skyrocket.
Both Wagner and Lignomat offer deeper reading depths, but Wagner’s IntelliSense™ Technology differentiates surface conditions for a much more highly accurate moisture reading from IN the wood, and offers a 3D average of the readings to avoid mis-reads from wet or dry pockets in the wood.
To learn more about handheld wood moisture meters with IntelliSense™ Technology, visit Wagner Meters’ site and view their line up.
Featured Moisture Detectors
 Wagner L606 |
 Wagner MMC220 |
 Wagner MMI1100 |
|
|
|
| Learn More | Learn More | Learn More |
Resources
After you buy your moisture detector, you’ll need to know:
- How to use your moisture meter
- Information about the wood you’re measuring
- The acceptable moisture content for your application
- Where to go for repairs
Let us know what problems you have or other resources that you would like to see listed here.