Woods have Moisture Content (MC) in it, and it can’t be too high or low. If it happens, do you think too dry or too wet lumber is still for woodworking? Find out the answer in this article.
It is not advisable to use neither too dry nor too wet lumber in woodworking. If it’s too dry, it means it has a low Moisture Content that may produce fire and brittleness. On the other hand, too wet wood means too high Moisture Content resulting in fungi formation until it gets rotten.
Moisture is essential for a smooth and seamless cut. However, there are other pitfalls of using too dry and wet wood, especially for your tools. Find out what are those, and know the right Moisture Content for lumber.
How to Tell If the Wood Is Dry Enough for Woodworking?
There are some ways to tell if the wood is dry enough and ready to use for your woodworking. It prevents encountering common issues of having too dry or too wet timber, like splitting and shrinkage. Check out these secure method to check the dryness and Moisture Content of your wood.
- Use of Moisture Meter
Technically, the best way to tell if the wood is ready is to use is through a moisture meter. You can purchase it for as low as $20 or $50 and higher for the branded ones. A Moisture Meter is a tool that will give you accurate readings of the MC. It is an excellent investment, especially if you want to be a professional woodworker in the future.
Cut a 1/4 inch off the long grain side the whole timber. Record its weight, width, and length and set it outside in the sun for a day. Then, measure the wood all over again using the Moisture meter. If it got thinner or smaller by 1/32″ or more and lost 5 to 10 percent of its weight – you have a wet piece of wood. Know more about Moisture Meter when you read our article about cutting damp wood with a Circular Saw.
- Feeling it Against Your Skin
It may be less accurate and a longer process than using a Moisture Meter, but it’s worth giving a try if your wood is small and tiny. Hold it against your skin on your forearm. If it feels cold, it’s probably above 7 percent MC. If it feels noticeably chiller than the current temperature, it may not be dry yet.
- Comparing Wood’s Weight
Another test that you can do is to use a weighing scale and get the weight of the wood. Let it sit for a month up to three. After that, recheck the lumber and see if there’s any difference in its mass since the last time you record it. If not, your wood is ready for some woodworking actions.
- Heating a Small Part of Wood
Start by cutting off a small piece at the thickest part of your wood. Get the weight of it, and place it in the oven for approximately 100 degrees Fahrenheit. Do it for every two hours at least four times or until the weight stops going down.
The Moisture Content percentage is the mass of the water that you lose as you heat the wood, divided by the weight of the current dry lumber, times 100. Heating helps in getting the right Moisture Content of the lumber because sometimes it can be dry outside, but the center is still wet.
What Happens When Wood Have Too High or Too Low Moisture Content?
Moisture levels vary from piece to piece, and from source to source. Wood is a hygroscopic material, which absorbs condensable vapors and releases moisture in the environment.
The cycle never stops and will continue to work as it tries to balance the atmosphere. No matter how Sawmills closely monitor wood’s Moisture Content and remove excess moisture from the timber, somehow, it’s an uncontrollable factor. However, anything too high or too low can be problematic and disastrous while woodworking.
- Disadvantages of Too High Moisture Content
- Shrinkage. Wood with a high MC level will start shrinking in all dimensions once it begins losing excess moisture. Timber’s width and thickness affect the most, which may lead to different awful sights like buckling, gaps, or cupping.
- Wood Damage. Too high MC level causes wood fibers to soften, which generates easy tear and rip out. Even sanding can break the surface. It would be almost impossible to use any tool on too wet wood. Additionally, High MC wood is more prone to kickbacks as well.
- Tool Wear. Some tools, like a plane, jointer, sander, and other cutting tools, can experience damage and post danger to you. Moving parts of any device can catch wet sawdust, which may cause rust on metal parts and reduce their lifespan.
- Adhesive Problems. It’s harder to glue up wood joints that have high MC levels. It can’t hold appropriately for an extended period and can be at risk as the glue dries because the wood tries to pull away from one another due to shrinkage.
- Disadvantages of Too Low Moisture Content
- Brittleness. Too dry wood leads to brittleness, which leads to splits, cracks, knots, loss, and other extreme damage. It’s harder to nail, turn, or saw especially across the grain. Carving may also cause splintering on the surface.
- Tool Wear. Using tools like chisels, drill bits, and saw blades over a super dry wood makes them dull faster. It shortens the lifespan of the tools and may get damaged easily.
- Splitting. Dry woods become easier to split – whether it’s a hardwood or softwood. It’s because they have less moisture. So regardless of the tree species, it has less resistance in cutting or breaking.
Understanding Moisture Content in Wood
It is essential to understand how Moisture Content works in wood whether you’re a woodworker, carpenter, builder, or anyone who works with wood.
It dramatically affects the whole process and the result of your project. We already know that either too dry or super wet lumber is not good, but here are more facts that you should know about Moisture Content.
- Its Relationship With the Surrounding
As mentioned, wood is hygroscopic and has a direct relationship with the environment. As the humidity in the air increases, the MC level also increases – and vice versa. These changes may cause the wood to shrink or become brittle. Hence, the end-use of the wood product is a vital thing to consider in determining the acceptable MC level.
- It’s All About the End-Product and Its Supposed Location
“The EMC of air is numerically equal to the MC that will eventually be attained by any piece of wood when stored indefinitely at a particular humidity,”Dr. Eugene Wengert – professor, and extension specialist in wood processing of the Department of Forestry at the University of Wisconsin-Madison.
Equilibrium Moisture Content (EMC) is when the wood neither gain nor lose moisture content. Always maintain a Moisture Content that’s within 2 percent points of the EMC of the location where the would-be. For example, if you bring home wood with 8 percent MC and store it to your garage, the wood could absorb an extra 6 percent MC or more. So, that would be an increase in the MC level.
- Consider the Wood’s Storage or In-Use Location
Depending on how you want to use the wood, you must allow it to come in balance with the Average Relative Humidity (RH) of the location where you will store or use the wood.
If the area has high humidity, lower the MC level of the timber, so it has space to absorb moisture once it reaches its final destination. This way, it avoids having too much Moisture Content.
On the other hand, make sure that the wood has sufficient moisture if the humidity in the place is low. It is to avoid getting it too dry once it gives off moisture in the air due to little steam. You can’t see moisture, but you can feel it. Using Moisture Meter is the best way to know the exact MC level – both in the wood and the surrounding.
What Is the Moisture Level Acceptable in Wood?
The MC of newly cut wood ranges from 40 to 200 percent. Then manufacturers will decrease it by drying depending on its final use. As a rule of thumb, the moisture level in wood for indoor purposes is at least 6 to 8 percent. On the other hand, it should be 6 to 9 percent for furniture and 9 to 14 percent for outdoor construction. Overall, the average moisture content (EMC) varies from 7 to 19 percent.
The moisture level depends on your project type and thickness of the wood. Always consider the Average Relative Humidity (RH) in the environment of the location where you will use the wood to determine moisture content accurately.
Failure to have a balance MC level in wood with the RH in its end-use location may result in warping, cracking, buckling, diminished wood strength, and corrosion of fasteners. Worst of all, wood may experience fungal growth after construction resulting in rotten timber.
At What Moisture Content Does Wood Rot?
Wood starts to suffer destruction if the Moisture Content (MC) maintained 20 percent and above for an extended period. Usually, the relative humidity of the surrounding air is approximately 80 percent.
Since all lumber correlates with the air humidity in its environment, staying at a 20 percent higher MC level, with more than 80 percent RH for a long time can ruin the wood.
Wood may start to be moldy within several months. Once the Average Relative Humidity exceeds 90% and the lumber remains at over 20 percent MC level, it begins to rot given that the temperature is between +0 to +40 degrees Celsius.
There are some places with sub-zero temperatures that have more relative air humidity of about 85 percent, but the heat is not enough for fungus and decay to develop. Hence, fungal spores and rot fungus also need oxygen and nutrients to thrive in the wood.
Are Rotten Wood Safe to Hold?
Even fungus can only penetrate the wood’s surface; the spores that they spread is harmful to health. It can give people various allergic reactions and mild symptoms of poisoning. It may include severe runny nose, dizziness, and painful headaches. So, it is crucial to take the occurrence of mold seriously. Also, don’t forget to wear masks, goggles, and gloves when disposing of them.
Is It Easier to Saw Wet or Dry Wood?
It depends on the type of lumber that you’re trying to cut. Usually, dry woods are less complicated to cut because it is less dense and resistance. However, moisture in the timber also acts as a natural lubricant so it can make the saw blade dull.
On the other hand, wet woods are more difficult to cut because it is denser. If you split the lumber, it will give off moisture and dry faster, then becomes easier to cut. However, it is not a common practice to split wood, especially woodworking.
How Long Does It Take for Wood to Dry?
Drying out damp wood may take approximately one year per inch of wood thickness. Generally, it depends on the overall size of the lumber.
For most wood manufacturers, it is the amount of time they expect to create woodworking lumber like plywood. However, it may speed up the process of at least six months if you’re going to split the wood and expose it to the sun.
Can I Still Use Too Wet or Too Dry Wood?
For super dry woods, it’s better not to use them. There’s no good using dry lumber because it will only crack whatever you do. In the case of too wet wood, if there’s a chance to save it – do it. They have higher usability than too dry timber for as long as there is no formation of fungus, yet.
It is more common to have wet woods, but too wet is an extreme condition. There are times when you have to work with moist lumber, or if you need a water-resistant wood. So, as your guide, here’s a list of various wood types that you can pick.
- Mahogany. It has a beautiful grain that can stand well to water. You can do a durable boat using this. Mahogany can resist shrinking, warping, and swelling due to its ability to withstand wear and water.
- Oak. It’s flexible and sturdy even when exposed to moist conditions. Oak is resistant to absorption and warping.
- Walnut. It’s another strong and fine-textured wood that can resist shrinking and warping. Plus, it’s easy to work with it and offers beautiful finishes.
- Maple. It is a hardwood with a beautiful grain that can be tough when exposed to water. However, be careful as it may experience moderate shrinkage with non-stop exposure to water and other humid conditions.
- Pine. It is a softwood that gives adorable finishes and can resist moisture, shrinkage, swelling, and warping for extended periods.
- Cedar. It’s another softwood that has a uniform texture that adds brilliance to your workpiece. Best of all, it is excellent in resisting molding, decay, and rot. However, too much exposure to any humid conditions may cause moderate shrinkage and expansion.
- Teak. It is a prevalent option for its natural ability to resist warping, cracking, decay, and rot. Additionally, it stands up extremely high against moisture exposure.
FREQUENTLY ASKED QUESTIONS
Can You Still Build Something with Wet Wood?
If it’s treated wood, it’s a bad idea because it can cause shrinkage, cracks, gaps, and squeaks. It’s much better if you let it dry first and get the right Moisture Content level to avoid having any issues later in the process. It is recommendable to sit the timber for a couple of weeks to get accustomed to the environment’s air humidity.
Can Wood Get Too Dry?
It can get super dry to the point that it can self-destroy. Too dry wood has less moisture that can also produce fire – depending on the climate, storage, and other environmental conditions.
Does Cutting Wet Wood Dull a Chainsaw?
A chainsaw is the best kind of saw to cut wet wood. There would be no issue cutting it because the extra moisture content on the lumber can’t make any difference. Just be careful in cutting in wet conditions, because it may be too slippery and it’s more prone to accidents when running a chainsaw.
Some types of woods are water-resistant, but it doesn’t mean that it can withstand very long and non-stop water exposure. However, too dry wood is useless for any project because it will cause brittleness and splitting unless you want a unique design.
As a woodworker, consider your plan, the location of its storage, and where you will use it because air humidity affects the Moisture Content of the lumber. If possible, purchase a Moisture Meter to keep track of your timber’s MC level as well as your surroundings – it the most accurate way to know these critical factors.