Wood warping is a common and frustrating issue for woodworkers, furniture
manufacturers and importers. Wood warping can affect the products’ appearance, function, and quality, so that it may waste your time and money.
There are ways to prevent and fix wood warping and keep your wood products in good condition. In this article, we will explain common reasons causing wood warping and tips to prevent it.
What causes wood warping?
Wood is a natural material with pores that can absorb and release moisture from the air. So, uneven moisture changes in the wood cause wood warping. When the wood is very wet, it gets smaller as it loses water until it is as wet as the air, which is called the same wetness point (SWP), or equilibrium moisture content (EMC). When the wood has a low moisture content, it swells as it absorbs moisture from the air until it reaches EMC. This relationship helps predict how the wood will behave as it adapts to different conditions.
However, other factors can affect the rate of moisture change and cause wood warping, such as the size of the piece of wood, coating, grain orientation, ambient air temperature, wood type and quality. So by understanding these factors, you can prevent wood warping.
How to prevent wood warping?
Now that you know what causes wood warping, you can take some simple steps to protect your wood products from warping and keep them in good shape. We provide some of the best tips on how to prevent wood warping.
Use stable types of wood.
Some types are more stable and less likely to warp or crack than others, depending on their density, grain orientation, and natural moisture content. For instance, cedar, fir, and redwood stay in shape better than pine, spruce, and poplar. You can also choose the wood that has been quarter-sawn or rift sawn, which means the grain is more perpendicular to the surface and less prone to shrinking or swelling.
Seal the wood with a high-quality sealer or oil.
Sealing the wood helps to create a barrier that prevents the wood from losing or absorbing moisture from the surrounding air. The seal protects the wood from heat, UV exposure, insects, and pests. You should apply the sealer or oil evenly on all sides of the wood and reapply it periodically according to the manufacturer’s instructions.
Lay it flat during storage.
Storing your wood products properly will also help to prevent wood warping. You should them flat on a level surface and avoid stacking them on top of each other or top of warped boards. By doing this, you can prevent the weight and pressure from causing the wood to bend or twist.
Before using your wood products, let them acclimate to their environment for at least a few days. This means letting them adjust to the temperature and humidity levels of the room where they will be used or installed.
Dry it well.
If your wood is fresh or wet, make sure it’s dry before you use it. You can choose to let it dry naturally or use a special oven to dry it faster.
Monitor moisture content regularly.
You can use a gadget that tells you how wet the wood is by poking two metal sticks into it. You want your wood products to be as wet as the air around them. For example, if your indoor relative humidity is 50%, you want your wood products to have a moisture content of around 9%. This will ensure that your wood products are stable and less likely to warp.
Avoid fast drying.
Fast drying is one of the main causes of wood warping. It happens when one part of the wood dries faster than another, causing uneven shrinkage and stress. Stay away from bright sun, hot things, blowers, or dryers. You should also avoid applying too much pressure or weight on your wood products while they are drying.
Avoid excessive drying.
It happens when the wood loses too much moisture and becomes brittle and prone to cracking. You should avoid storing your wood products in dry environments such as basements or garages to avoid excessive drying. Try not to use chemicals or solvents that can dry out the wood.
How to fix wood warping?
Sometimes, despite your best efforts, your wood products may still warp. If that happens, there are still ways to fix wood warping and restore your wood products to their original shape.
Using heat to fix wood warping
Utilizing the sun to fix your wood warping issue. With the sunlight method, you’ll need a damp towel, a few days of sun, and some time. Take your damp towel and wrap it around your warped wood. After that, put the covered wood on a level surface outside, with the sunken side up and the raised side down.The sun will heat the damp towel and the wood, causing the wood to expand and flatten. You may need to repeat this process for several days until the warp disappears.
Using an iron
You’ll need a damp towel, a steam iron, an ironing board or other flat surface. Cover your twisted wood with the wet towel and put it on the ironing board with the humped side up and the dented side down. Switch on the steam iron and make it as hot as possible. Press the iron over the wrapped wood slowly and evenly over the entire surface. The steam and heat from the iron will cause the wood to expand and flatten. You may need to repeat this process until the warp is gone.
You’ll need some weights and some time. Put your bent wood on a smooth surface inside, with the hollow side up and the bulging side down. Place the weights evenly over the entire wood surface, ensuring that they cover the entire warped area. Leave them there for several days or weeks until the warp is gone.
You’ll need a large container filled with water, such as a bathtub or a bucket. Submerge your warped wood in the water and leave it there for several hours or days until it becomes saturated. Next, you can remove it from the water and lay it down on a level surface inside, with the curved-in side up and the curved-out side down. Place some weights evenly over the entire surface of the wood and leave them there until the wood dries completely.
Sometimes, none of these methods may work to fix warped wood, especially if the warp is too severe. In that case, you may need to replace your warped wood with a new piece that matches your original product.
Conclusion: How to prevent wood warping and preserving product quality
Wood warping is a common and frustrating issue for anyone who works with wood. It happens when the wood changes its shape due to uneven moisture changes in the wood. This can affect your wood products’ appearance, function, and quality and cause you to waste time and money.