How to tell if wood is dry enough for woodworking? Let’s learn how to measure the water content of lumber and the right equipment through this article!
Testing the humidity of wooden pieces
One of the common properties of wood is its ability to absorb moisture as strong as a sponge. It will cause quite a few problems for the woodworking process.
A piece of timber that dries out and releases water tends to shrink. It contributes to damage and warping of your work.
So, how to know if wood is dry enough for woodworking? The optimum wood moisture content for most projects is between 6 and 8%. The best way you can test it is to use a measuring meter.
To learn more about how to use this tool and fantastic tips, let’s read on!
How Dry Should Wood Be For Woodworking?
You can not use wet lumbers
If you are just a regular home woodworker, the wood you pick up in the lumber yard is dry enough for immediate use. It’s safe for your project and has just the right amount of moisture.
Acceptable moisture content for lumber species is usually 6-8% for interior wood, and 9-14% for exterior wood. There are two factors to assess the acceptability of moisture, including:
- The intended end use.
- Average RH of the environment using lumber.
These two factors make determining ideal humidity quite challenging, but you should keep these numbers in mind. Wood with a moderate level of humidity is suitable for any of your carpentry projects.
If the humidity range exceeds the allowable level, wait a little longer for the lumber to dry completely.
How To Tell If Wood Is Dry Enough For Woodworking?
To determine optimal humidity levels, you need to have a way to measure and calculate them. Fortunately, you won’t have to do it alone. There are many simple tools and methods that you can follow.
This section will introduce you to both traditional and modern methods. Depending on the situation, you can make a more suitable choice for yourself.
Oven Dry Testing
Oven dry testing
The oldest method of measuring the moisture content of lumber is the kiln drying test. Although this process is quite time-consuming, it gives incredibly accurate results.
Take a test wood sample and check the weight periodically. Usually, you will dry it in a special oven or drying oven. When the importance of the lumber sample stops changing, compare it with the original weight.
The weight difference is the basis for calculating the original moisture content.
Some limitations of this approach include:
- It can render the wood unusable: If you over-dry the specimen, you won’t be able to use it again. Temperature alignment is essential with this step.
- This method requires a specialized oven or drying oven: This appliance is not the same as the basic stove on your kitchen counter. Other ovens will not give accurate results.
- It takes time: You need to do the drying process slowly and slowly to avoid burning the lumber. This method can take up to hours.
With the above disadvantages, the furnace test method is not suitable for those who want to do carpentry as a hobby. It takes time and requires quite a bit of skill. You can refer to this video to get a better overview of the method.
Moisture Meter Testing
Moisture meter testing
Currently, you can use a moisture meter to check the water content in wooden lumber. There are two main types of gauges, pinned and unpinned.
Pin-Type Moisture Meters/Sensors
This type of meter attaches electrodes to the lumber and uses a resistor to calculate the humidity inside. Usage is straightforward, just take lumber and insert the electrodes, you can start reading.
The greater the water content, the bigger the resistance. It would help if you dug deeper into the lumber as it would give more accurate results. This action also helps you spot potential pockets of moisture.
This device’s ability to measure and detect deep water content is a plus point. You can read the results continuously until you get an overview of your lumber. It also takes a little time but is still faster than the first way.
The most significant limitation of the pin-type meter is that it can only measure accurately around the area of the pins. So, you won’t tell if there’s a bag of moisture if you don’t detect it. This feature, in contrast, allows for precise positioning of the moisture bag.
Pinless Moisture Meters/Sensors
Instead of penetrating the wood, the pinless meter uses a sensor pad to read the lumber in contact with the surface. This unit’s humidity reading is available from ¼ – ½ inch depths.
This meter is the perfect choice for quickly scanning large areas of the subject. It won’t take long to stick electrodes on your lumber.
Repeat this process on different areas of the lumber for the most accurate results. However, this device also has a few limitations.
Pinless gauges are suitable for lumber with flat surfaces. If you have a rough log, it won’t work.
The scan depth of this device is also not fixed. With pieces of wood that are too thick, the results will not be detailed and comprehensive.
The method of operation of the pinless meter is to use electromagnetic waves to scan the surface and check the wave’s distortion to calculate % MC. Metallic materials can interfere with the signal, causing false positives.
How To Dry Wood Properly?
One thing that you need to keep in mind, wood is a damp sponge. The surrounding environment dramatically affects the ability of the lumber to absorb and release water vapor.
The term equilibrium moisture content (EMC) means when the wood is in equilibrium with the humidity of the air around it.
The wetter the air will increase the water content of the lumber and make it bigger. In contrast, dry air makes lumber drier and smaller. The secret to keeping lumber in tip-top shape is to balance the wood’s humidity with the most waterless interior environment.
Air-drying is a process that takes a long time. You need to stack lumber blocks on top of each other and expose the sides to the air. The rule of thumb is one year for every inch of thickness for the wood to be dry enough for work.
This process is extremely time-consuming and laborious. Therefore, professional workers will need the support of a specialized drying oven to quickly dry materials under controlled conditions. These furnaces are shaped like large, insulated rooms with an ideal drying environment.
As the temperature and airflow increase, drying takes place. The outer shell tends to be easier to dry than the inner core.
Poor kiln management can lead to uneven drying. When the outer shell dries too quickly, it separates from the core layer and creates a honeycomb condition. This condition damages the material and loses its aesthetic appeal.
You need to choose quality and qualified wood for successful woodworking projects. Whether you are a hobbyist or a professional carpenter, there is always the right tool for you.
We hope this article has brought you helpful knowledge. To find out more information related to woodworking, don’t forget to visit our website.
Thank you for reading!