If you’re reading this article, you probably already know what moisture meters are. However, if you don’t, here’s a quick overview…
Moisture meters are small, hand-held devices (either analog or digital) that measure the moisture levels of various materials including wood, paper, concrete, drywall, and even soil. Wood moisture meters are very common and this article focuses exclusively on them.
Wood moisture meters are used by both serious hobbyists and professionals. They use them because when you’re working with wood, too much moisture can cause serious problems with your projects. It doesn’t matter if you’re building a simple kitchen cabinet or an entire house, wood needs to be at the correct moisture content (and this varies) before it’s used in construction.
The only way to ensure that wood is at its correct moisture content is to test it using a quality moisture meter.
Two Types of Moisture Meters: Pin and Pinless
Wood moisture meters come in two varieties: pin (also referred to as pin-type or pin-style) and pinless. In this section, we’ll go over the basics of each including their particular sensitivities.
Pin Moisture Meters
A pin moisture meter contains two small pins (probes) that need to physically penetrate the wood in order to take a moisture reading. After the pins have been pushed into the wood and the meter turned on, an electrical current flows between the two pins that measure the amount of resistance encountered.
Pin meter technology takes advantage of the fact that water (with salts and impurities) is a great conductor of electricity, while wood isn’t. That means the drier the wood, the greater the resistance.
The length of the meter’s pins determines the depth of the moisture reading. For the deepest readings, you can use something called a hammer probe. This is an external device that attaches to the pin meter and will allow you to hammer the pins deep into the wood.
Pin Meter Sensitivities
Pin meters are sensitive to both the wood’s temperature and its chemical makeup, which varies from species to species. This is why all pin-style meters should come with temperature correction charts or also ask you to enter the species of wood you’re measuring before you take a reading.
Although quality pin meters can be accurate, their most obvious drawback is the fact that they create holes in the wood. Remember, the pin meter is only measuring the moisture content between the two pins. This means that unless you’re measuring the moisture content of a very small piece of wood, you’re going to need more than one reading in order to get an accurate overview of the piece’s moisture content. In other words, more than one reading using a pin meter means more than two holes in the wood. This means that while pin wood moisture meters are great for measuring the moisture content of firewood and lumber, they aren’t the best choice for measuring the moisture content of fine furniture and hardwood floors.
Another drawback with pin meters is the fact that the pins tend to either bend or break. This happens because wood density varies according to species and the denser the wood, the harder it is to push the meter’s pins into it. Since bent or broken pins will need to be replaced, this is an additional cost of time and money that can really start to add up if your meter gets a lot of heavy use.
Perhaps the biggest problem with using a pin meter is that if you need to measure a lot of pieces of wood to ensure a batch of wood is at the proper moisture content it can take a lot of work. This effort is required as it takes a lot of time and energy to drive the pins into the wood so many times.
As with all moisture meters, pin meters require you to enter the species setting into the meter in order to get accurate readings.
Pinless Moisture Meters
Unlike pin wood moisture meters, pinless meters are able to take a moisture reading without causing damage to the wood. This makes pinless meters the option of choice when measuring the moisture content of fine wood furniture and hardwood flooring.
Pinless meters are also able to quickly scan large areas of wood in just seconds. This is in contrast to pin meters and the fact that each reading only measures the moisture content between the two pins.
Sensitivities of a Pinless Meter
Like pin meters, pinless meters also have their sensitivities, in this case, wood density of the various species. Therefore, before you take a moisture reading using a pinless meter you’ll need to enter the species setting of the wood species whose moisture content you’re measuring, which is typically calibrated to specific gravity.
Both pin and pinless wood moisture meters are sensitive to moisture on the surface of the wood. That’s why you should wipe away any visible moisture on the surface of the wood and then wait for around 30 minutes before taking a moisture reading. If you don’t, the reading could be inaccurate. However, there are some high-end wood moisture meters that have the advanced technology necessary to be much less sensitive to surface moisture. See our list of best wood moisture meters for more information.
Which Moisture Meter Is Easier to Use: Pin or Pinless?
We get asked this question quite a bit and here’s our answer…
It really isn’t a question of which moisture meter is easier to use. It’s about which moisture meter is the right choice for you.
Are you measuring the moisture content of firewood, or do you need to find the moisture content of wood that’s going to be used to construct high-quality, custom wood furniture? If it’s cheap lumber or firewood, a pin-type meter is probably a decent choice.
If you’re working with wood intended for use in fine wood furniture, you’ll almost certainly want to buy a pinless moisture meter. Also, if you need to measure large quantities of wood, you will want to use a pinless meter.
Let’s take a closer look at how each wood moisture meter works so that you’ll have a better idea of what we’re talking about…
How to Use a Pin Moisture Meter
Step 1: Insert the pins into the wood. Push firmly, but be careful not to bend or break the pins. If you’re testing the moisture content of one of the denser wood species, this might be somewhat difficult. This is why it’s always a good idea to have spare pins on hand.
Step 2: Turn on the meter and take a moisture reading.
Step 3: Repeat steps one and two as many times as necessary to get an accurate overview of the wood’s moisture content.
How to Use a Pinless Moisture Meter
Step 1: Turn on the meter.
Step 2: Place the pinless meter’s electromagnetic scanning plate firmly on the wood and take a moisture reading.
Step 3: Move the meter to take another reading. Continue until you have an overall picture of the wood’s moisture content.
So, which one is easier?
We’d say that if you’re measuring the moisture content of firewood or rough lumber, the pin meter is probably easier to use. This is because rough lumber or firewood has a rough surface. This makes it difficult to place the pinless meter’s scanning plate firmly on the wood’s surface. Since you almost certainly don’t care about creating holes in the wood, a pin-style meter is a good choice.
On the other hand…
If you measure the moisture content of fine hardwood flooring or wood furniture, you probably don’t want a number of unsightly holes in the wood. Therefore, a pinless meter is your best choice.
If you work with large amounts of wood, you will want to use a pinless meter. It takes a lot of time and energy to drive the pins into the wood to ensure that the moisture content is correct for a large batch of wood.
Both high-quality pin and pinless wood moisture meters can provide accurate readings if used properly.
Which Type of Meter Is Preferred By Woodworkers? Pin or Pinless?
The short answer is…
Pinless meters are easier for woodworkers. But it’s worth taking a closer look at why this is the case.
Pinless Meters Don’t Poke Holes in the Wood
It goes without saying that professional woodworkers and hobbyists want their projects to look good. In fact, for professional woodworkers, beautiful projects that people want to buy are their bread and butter. Therefore, they don’t want to do anything that would negatively affect their physical appearance. That’s why — more than 9 times out of 10 — they prefer pinless wood moisture meters.
Pinless Meters Are Easy to Use
With a pinless meter, all you need to do is turn it on and start scanning. They really are that easy to use. You don’t need to worry about properly inserting the pins or struggling to push the pins into denser wood species. (Improper insertion of pins can cause inaccurate readings.)
Pinless Meters Are Quick
High-quality pinless meters are able to quickly scan the whole board and give you an accurate moisture content reading within seconds. Compare this with the fact that pin-style meters only measure the content between the two pins. In other words, with pin meters, you will almost certainly need to take several readings in order to get an accurate picture of the wood’s moisture content — some in the center of the board face, some near the edge, and some near the ends. This takes time and, as we’ve already discussed, creates unsightly holes in the wood.
Pinless Meters Are Accurate
Finally, pinless meters are accurate — at least there are some very accurate ones available on the market. They can typically take deep readings up to ¾” below the surface of the wood. If you want to take deep readings with a pin meter you’ll need to use an external device called a hammer probe using insulated pins. Otherwise, a pin meter will simply measure the path of least electrical resistance — whether that’s near the surface, or near the tips of the pins.
If you’re in the market for a quality wood moisture meter be sure to check out our review of the top moisture meters before you buy.