How to determine the moisture content of wood in DIY projects?
One of the oldest methods for measuring the moisture content of any hygroscopic material is the oven drying test. This test has two methods described in ASTM D4442, Method A and Method B (referred to as "primary" scientific testing and "secondary" methods, respectively).
The general strategy for oven drying tests is to dry wood in a well ventilated oven or kiln for a long period of time. After each drying cycle, weigh the wood to verify its weight. Repeat this process until the weight of the wood stops changing.
By comparing the dry weight of the wood with its original weight, you can establish a very accurate original% MC for the wood.
For example, suppose you have a piece of wood weighing 10 pounds and pass it through an oven drying test until it stops losing 9.5 pounds. In this case, the% MC of wood is approximately 5%, as 0.5 pounds of wood weight is water, and 0.5/10=0.05 or 5%.
In general, oven drying testing is considered an accurate method for determining moisture content in moisture absorbing materials such as wood - assuming the test is conducted properly.
However, DIY enthusiasts usually do not like this method for the following reasons:
This is very slow. Testing moisture by drying wood samples may take several hours, and the flushing process can burn and damage the wood.
In many instances, rendering tested wood cannot be used. Although the% MC is determined by the weight of water in this process, over dried wood may not be suitable for your original use due to deformation caused by heat exposure and rapid drying.
Not everyone has a suitable type of oven. Professional carpenters may only be able to use kilns for drying wood, but homemade stoves may not have ventilated ovens, which can achieve the goal of evenly drying wood. An oven that cannot maintain an appropriate temperature or provide sufficient ventilation may cause deviations in test results.
These three questions alone are enough to prevent most self-help enthusiasts from attempting to use oven drying testing methods for woodworking projects.
However, there is a faster way to check the moisture content of wood, which is still reliable enough for your DIY wood project testing needs:
