Wood moisture meter is a device used to determine the percentage of water content in wood. The design of the machine is usually a compact, portable design, the top has an electronic screen and has two probe needles on the front for touching the material.
Wood material is very sensitive to its moisture content. Just a slight change in the water content of wood can lead to variations in its physical properties. Therefore, the craftsman usually measures the moisture content of the wood material before putting it into production to ensure the quality of the product. A wood moisture meter will be a powerful tool to help workers grasp humidity information easily.
Table of Contents
- What is a wood moisture meter?
- What is the moisture content of the wood?
- How to use a Wood Moisture Meter Accurate?
- Top 7 Best Wood Moisture Meter Review 2021
- #1 General Tools MMD7NP Pinless, Non-Invasive, Non-Marring, Digital Moisture Meter
- #2 General Tools MMD4E Digital Moisture Meter
- #3 Protimeter BLD5365 Surveymaster Dual-Function Moisture Meter
- #4 Tramex MEP Moisture Encounter Plus Moisture Meter
- #5 EXTECH MO257 – PINLESS MOISTURE METER
- #6 Lignomat Moisture Meter Mini-Ligno E/D
- #7 Protimeter Mini General Purpose Moisture Meter
- Working principle and construction of a needle wood moisture meter
- How is the impact of humidity on the quality of wood products?
What is a wood moisture meter?
A hygrometer is a device used to determine the percentage of water content in a material. Is an application used very popularly in various industries. Especially for the wood industry, it is indispensable to have a moisture meter. The design of the machine is usually a compact, portable design, the top has an electronic screen and has two probe needles on the front for touching the material.
What is the moisture content of the wood?
Wood is a material made of Cellulose, so it is easy to absorb or release water from the surrounding environment. For a seasoned craftsman will understand that, wood needs to put a certain humidity to be produced. Industry experts all say that the moisture content of wood is related to 75% of the quality of the product. Therefore, the wood production and processing workshops must always monitor and control the moisture content of the wood to ensure the output of product quality. The problem is how much wood moisture is up to the standard?
As mentioned in the first section, the wood will be least affected by moisture when it reaches the EMC state. So to standard the moisture content of wood must be equal to EMC. Wood moisture meter also allows reading relative humidity of wood (EMC). If you are an experienced person, it will be easy to see that the equilibrium moisture content of the wood in the drying room: 8-12%, and the equilibrium moisture content of the wood when left in the air for 15-18%.
Wood moisture is the percentage of water present in the wood relative to the volume of dry wood. Under normal circumstances, wood and wood products have a certain moisture content. The formula for calculating moisture is as follows:
W = (Gs – Ggo) / Ggo × 100%
W1 = (Gs – Ggo) / Gs × 100%
Gs is in the amount of wet wood
Ggo is the weight of the dried wood.
W is the absolute moisture content of the wood
W1 is the relative humidity of the wood.
How to use a Wood Moisture Meter Accurate?
Press the Power key “Power / H” to start the system, and the LCD shows “0.0%” and start measuring the symbol “SCAN”.
Press the “M” key to select the relevant crop in “1,2,3,4” displayed on the LCD screen. See Table of types of wood and materials for details. If the tree species is unknown, it is a suggestion to select default tree species 3.
Insert the 5mm probe into the material for measurement. This time, the reading on the LCD displays the moisture content of the measuring material.
When the “Power / H” key is pressed during measurement. This reading will be organized and “Fixed” the results will be displayed on the LCD screen. Press “Power / H” for the second time, the fixed function will be canceled.
After the measurement is complete, press and hold the “H” key (more than 2 seconds) to turn off the screen display system. The machine will be in shutdown mode. Close the probe guard cap, and the measurement ends.
Top 7 Best Wood Moisture Meter Review 2021
#1 General Tools MMD7NP Pinless, Non-Invasive, Non-Marring, Digital Moisture Meter
This wood meter from General Tools is a precise, powerful, and versatile digital model. You do not need to puncture the wood material to measure its water content and thus save your effort.
Besides, this model can also act as a leak detector. It can work with materials other than wood such as drywall and bricks. This will limit the dangerous problems that can occur when the humidity exceeds the limit causing rot from the inside.
Moreover, the device is also equipped with a color digital display to show the results after measuring the humidity. Thus, users will easily grasp information in the fastest way. However, this type of machine suffers from a limitation that is difficult to read information in low light conditions.
#2 General Tools MMD4E Digital Moisture Meter
General Tools MMD4E is chosen by many users because of its compact design, which can fit comfortably in the palm of the hand. Therefore, the use process becomes a lot easier. In addition, the machine is also equipped with a large LCD screen for users to easily read the parameters. Along with that, the control buttons are installed openly, so users can operate and control more easily.
In addition, the machine is also made up of high-quality materials such as stainless steel. In addition, the machine is manufactured from a modern technological line. Therefore, product life expectancy is quite high. If you are looking for a hygrometer to serve your work, this is the best choice.
#3 Protimeter BLD5365 Surveymaster Dual-Function Moisture Meter
The Protimeter Surveymaster moisture meter is not only suitable for casual users but also selected by many experts. Because it gives accurate and immediate results after measurement. Similar to other machines, the Protimeter Surveymaster is also equipped with a digital display that clearly displays the results so that users can grasp the current humidity situation. From there, there will be suitable solutions to overcome problems to ensure work efficiency.
In addition, this machine also has a built-in feature that automatically turns off when not in use. This can both minimize the obvious risks and help save energy. The intuitive control buttons are integrated onto the surface so the user can operate the most easily and conveniently. In addition, the device is also fitted with a batteryless sensor on the back for convenient use.
#4 Tramex MEP Moisture Encounter Plus Moisture Meter
Impresses users with the ability to accurately measure moisture through materials such as paint, roof coverings, ceramic tiles, etc. This model also has a function that emits a sound to warn of excessively high humidity levels. Thus, users will easily detect unusual problems so that they can come up with suitable solutions to ensure work efficiency and product quality.
Not only integrating many features, but the Tramex MEP moisture meter also has a compact design with eye-catching colors. Users can completely store it in their carry-on bag for use when needed.
#5 EXTECH MO257 – PINLESS MOISTURE METER
Extech MO257 is one of the top 10 best selling hygrometer today on Amazon online market. This machine has a very unique and innovative design. It allows the user to use a ball to measure moisture instead of a pin like other devices. Therefore, you will not need to worry too much about the surface of the material being damaged.
In addition, the machine is equipped with 2 adjustable alarm functions along with a storage bag. Not only that, many users also prefer the product because of its ability to read data even in low light conditions. In particular, the machine also has a measuring range running the interface from 0% to 100%.
#6 Lignomat Moisture Meter Mini-Ligno E/D
Lignomat Mini-Ligno moisture meter includes 2 pairs of measuring pins, carrying case, wristband with 9V battery, wood spot chart, manual. This machine is designed to be portable with a compact weight, so users can easily carry it with them to use anytime, anywhere.
The machine is equipped with two metal measuring tips with Led-shaped welding to display the results. After the moisture measurement of the material is finished, the results will be fully displayed on the screen.
This device is suitable for people specializing in furniture. Because it is used to measure the moisture content of wood in different states and conditions such as plywood, industrial wood, hardwood, wet wood, etc. In particular, the machine works quite stably and is not affected by the surrounding environment conditions.
#7 Protimeter Mini General Purpose Moisture Meter
The GE Protimeter Mini moisture meter is chosen by many users because of its ability to measure humidity for many different materials such as floors, wood, concrete, painted or varnished surfaces, etc.
Not only does it have a rugged design, but it also delivers accurate results that help ensure optimal work efficiency thanks to faster humidity reading. In addition, the led lights also have a color change feature to display humidity conditions. As such, users will find it easier to collect information.
In addition, the machine also has a compact, solid design with intuitive easy-to-use controls. With the auto-off feature, users will not need to worry too much about forgetting to disconnect the power after using it to ensure safety and limit fuel waste. In addition, the GE Protimeter Mini is used to measure moisture for other materials such as paper or fabric.
Working principle and construction of a needle wood moisture meter
#1 Principle of a wood hygrometer using a needle
The relative resistance of wood is greatly influenced by its resistance. The drier the wood, the greater the resistance. When we increase the moisture content of the wood, the resistance of the wood by the head decreases. Experts have taken advantage of the changing nature of the resistances present in wood to measure the moisture content of the wood. The method of measuring the resistance is based on two electrodes in contact with the wood fibers, from the resistance parameter obtained, the machine will automatically convert to the moisture content of the wood.
The needle resistance meter can have 2 or 4 probes. Each needle represents one electrode. When you need to measure the moisture content of wood, you just need to insert the probe into the grain of the wood. Automatically the screen will display the measurement results corresponding to the available humidity on the wood. The lower the moisture content of the wood material, the higher the impedance will be, whereas the higher the moisture content, the lower the impedance will be.
In addition to the resistance factor, the ambient temperature is also a factor affecting the moisture content of the wood. Therefore, when measuring humidity you need to note at what temperature you are measuring. Because when measured at a temperature of 35oC will have a completely different value than when measured at 25oC.
#2 Structure of the moisture meter
Body: Above is a large LCD display screen. There are 5 function keys. 1 side key and 4 front keys.
Contact sensor: Includes 2 needles as probes, mounted in front of the body. A measuring probe detachable from the camera body, when needed, plug it back in. Together with the electronic system, the parameters of resistance are converted to humidity.
Battery according to the device: 04 AA batteries, common type of battery.
Specialized carrying case.
How is the impact of humidity on the quality of wood products?
For natural wood products, moisture is the most noticeable factor that shows us the change. Because, the main characteristic of changes in humidity is the change in the water content of the wood. Once, with this change, the wood will also deform. Specifically, when the water function in the wood changes, it changes the volume of a block of wood. This changing feature is extremely important to carpenters.
For a block of wood with a higher moisture content, the greater its volume. If the product is made from wood with high humidity is put into an environment with low humidity, after a while the block will shrink and create loose gaps. In addition, the high water content in the wood will easily cause the wood to deteriorate, mold, and rot. In contrast, a wood product with too low moisture is put into an environment with high humidity. After a while, the wood will start to absorb moisture, causing swelling, to an excess of compressive force, the joints will swell, causing warping and shrinking for the product.
Therefore, to avoid the above cases, it is common to bring the moisture content of the wood to the ideal state of equilibrium moisture content (EMC). EMC is the moisture content of the wood in equilibrium with the relative humidity of its surroundings. That is, the humidity of the wood will be equal to the relative humidity of the surrounding environment.
When the EMC moisture content is reached, the wood will not absorb any more or lose moisture. In fact, achieving EMC is extremely difficult, because you cannot control the relative humidity of the air. One can only bring the moisture of the wood closer to the EMC to minimize the effects of moisture on the product.