The only house I worked on as a carpenter from foundation all the way to "occupancy", the Journeyman Carpenter obsessed about who he hired to build the forms and pour the foundation. He told simply, a poor foundation will cause you extra time and work through the whole construction of the house. I have never forgotten that tip.
The same is true with woodworking, if we start off knowing as much as we can about the wood, it can save trying to fix things later on, which very often take more time to fix than doing it right the first time ...
If we are building backyard fences or rough chicken coups, maybe a dog house, we don't have to be that critical about joinery or worry so much about wood joints, but if we are making quality furniture, boxes, picture frames, tables, chairs, cabintery knowing the type of wood we are using and the moisture content of the wood can be critically important.
There are several reason why we need to know moisture content, one reason is that wood is constantly absorbing or releasing moisture. This means the actual wood can be expanding or contracting. The only time this is NOT the case is when the moisture content of the wood is equal to the moisture content and temperature of the air, and which we call the Equilibrium of the Wood, called the "EMC". How and where wood can expand or contract the most is shown in the picture below
You can find your own EMC for where you live in the chart below, this portion is copied from the US Gov website at
https://research.fs.usda.gov/treesearch/62243 ... which gives even more information.
What Could Possible Go Wrong?
There are many things that can go wrong using "wet wood"
Ends of boards can crack, and if the ends are not sealed, it is almost a guarantee they will crack.
Warped Wood, a common complaint from woodworkers. Wood dried too quickly can warp (it can also warp because of stresses in the wood that formed during growth). I have seen tables made with wet wood that as they dried the top warped so much only 3 legs are on the floor and the 4th is half an inch in the air!! or ... cabinet drawers that are warped so badly they need to be re-made, cabinet doors which solid panels where sides frames have either "blown out" or the panels have cracked and shrunk. Then there are the finishes that woodworkers apply on their projects where water is trapped in the wood and will actually "lift" some finishes off the wood, or in lesser cases will "fog" the finish of the wood making it look like the finish was of poor quality when really it's the water in the wood trying to escape.
Common Types of Moisture Meters
There are basically 2 types of portable moisture meters, the "Pin Type" and the "Surface Type"
Pin types read the content of moisture through an electrical connection between the 2 pins. This makes them ideal for people wanting to measure firewood logs or other uneven surfaces. Pin type meters work OK on wood boards but have definite disadvantages. The down side of these is that in order to work, the pins need to be inside the wood, which makes holes in the wood, that not every woodworkers is happy about and many suppliers don't allow pin reading in their wood as it can be more difficult to sell, or it needs to be discounted to sell ... not good. If the wood is a hard wood it can be very difficult to drive the pins deep enough to get a proper reading. Very often pins will bend and even break and bent pins means faulty readings.
Surface readers, for woodworkers a much better choice for a variety of reasons. First of all the can often give a more accurate moisture reading because they can read deeper into the wood. All wood should be measured in a few different places because variances in the wood could affect a reading so taking several readings will give a much clearer picture of the true moisture content.
Below is an example of what could be hiding either internally in the wood or behind the front surface of a board. In this case it is pitch pocket, (nut sometime knots can also affect readings) which can happen in any wood, but is more common in some woods. These are areas where pitch concentrates and is normally a place we want to avoid using this wood.
Below is an example where 2 finishing nails are driven into the wood, than a jumper with alligator clips bridging the nails to the meter demonstrates how easy it is to get a faulty meter reading by not reading deep into the wood.
Below ... a "Pin Meter Accessory Kit"
Surface Reading Wagner Moisture Meters
I have been using these types of meters for many years for reliable moisture content readings. I am confident when I arrive at the wood supply store I can use the meter to know exactly what I am buying and can even pick and choose which boards based on their moisture content *TIP - often the boards at the back vertical boards are drier.
Dual Depth Readings ... I highly recommend a meter that allows different depth readings, if you are using 3/4" to 1" boards a shallow depth is best but if you are using slab wood for resin pours, farm house table tops and or course all manner of lets, a deeper reading is imperative.
Selecting Species ... different kinds of woods have different wood hardness. This information needs to be given to the meter in order to get the most accurate readings. It takes seconds to re-set and ensures you get the most accuracy.
Species information and charts AND DOWNLOADABLE FILE (can be used on your phone)
Audio ... this is a nice to have feature. For me, any wood over 12% moisture content will need to be further dried. I set the audio on my meter to 14% so that when I am quickly scanning boards, when the meter beeps, I know the wood is over 14%, which is still fine, just alerts me to check it more closely.
How to select a Wagner Moisture Meter .. very easy
There are 4 basic models, all operate very similar.
Entry Level Orion 920 is a shallow only, measuring meter
Entry Level Orion 910 is a deep only, measuring meter
Colin's Pick - Orion 940 is DUAL Depth measuring meter, with audio
Advanced Woodworker - Saw Mill - Orion 950 Dual Depth plus advanced features
See ALL METERS - CLICK HERE
Any serious woodworker
