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What Is The Moisture Content Of Wood
- Apr 10, 2018 -

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The existing wood furniture in the market, whether solid wood furniture or board furniture, contain certain moisture. Some people say that wood is drier and better, but there is another objection. What is the best water content of wood?

In general, as long as the log of wood placed in certain environment, after long enough, the moisture content of timber tends to a stable equilibrium value, known as the environmental balance moisture content of EMC. If the moisture content in the wood is too high, the equilibrium moisture content of the environment is exceeded, and the thermal expansion and contraction principle of the wood itself will be wet and shrink, and moisture absorption and expansion. But either way, the wood will be deformed, so the wood should be dry and not as dry as possible.

The wood material that uses in general family, moisture content should be in 8 or so appropriate. The moisture content is too high or too low, can cause the wood in the home to do quality problem. As furniture material, the moisture content of plank should keep at around 12%, to guarantee the storage process of wood won't be affected by the environment is too big, common practice is on the side of wood coated with a layer of coating to prevent the wood is dry or absorb moisture from the outside world.

1. What is the moisture content of wood? To understand this concept first, let's start with the sources of wood water.

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Everyone knows that everything depends on water, a tree in the process of growth of a steady stream of absorb the moisture from the soil for its growth, tree has a very developed root system, in deep soil to absorb nutrients and moisture, and then nutrient and moisture transport through developed transport system by the end of each organ and branches, so as to complete the photosynthesis.

In cutting down trees made of wood when most of the water will still be left inside the wood, and even be sawed into different specifications of the board or the material, most of the water still does not leak, and in the storage, transportation or use in the process of production, also can absorb moisture from the outside. This is the concept of wood moisture content. Different species, different age, different times and different parts of a variety of factors will affect the moisture content of wood, so is very uneven distribution of moisture in wood.

 

There are three kinds of water in wood: absorbed water, hydration water and free water.

Exist in wood cell wall in the microfibril, composed of filaments between micro capillary system or adsorption in the surface of the microcrystalline cellulose molecules and the amorphous region of the free control based on known as absorbed water, all the tree species difference is relatively small, absorbed water is generally not more than thirty percent, the water absorption is not easy to escape, need specific environment will evaporate from the wood.

The hydration water will be in a strong chemical bond with the cell wall, and the water content in the general wood is very low, and it is difficult to dry or remove the water.

Free water remaining on the timber in physical way, is the largest proportion of wood moisture content, can reach sixty percent, to seventy, it exists in the pit on the cell wall of wood or the end of the catheter perforation and the cell cavity and the intercellular space of mutual communication of the capillary system, easy to evaporate, also easy to absorb the moisture in.

As furniture material, the moisture content of board to remain at around 12%, to ensure that the storage process of lumber won't be affected by the environment is too big, common practice is on the side of wood coated with a layer of coating to prevent the wood is dry or absorb moisture from the outside world, common safflower pears can see Africa side has a layer of red paint, a lot of people thought it was originally red wood decorative pattern, but actually it is coating, used to prevent moisture loss.

2. The importance of wood moisture content.

Why some wooden door, wooden floor, wooden furniture to wait for woodwork to sell go out to have the quality problem such as craze, deformation? How to reduce the loss of these problems to wood enterprises?

When the wood products are finished, the shape and material will not be changed again. The key factors that determine the inner quality of wood products are wood moisture content and dry stress. Manufacturing enterprises need to correctly grasp the water content of wood products. When wood products are used to achieve a balanced moisture content, the wood at this time is least prone to cracking and deforming.

In cutting down trees made of wood when most of the water will still be left inside the wood, and even be sawed into different specifications of the board or the material, most of the water still does not leak, and in the storage, transportation or use in the process of production, also can absorb moisture from the outside. This is the concept of wood moisture content. Different species, different species, different age, different times and different parts of a variety of factors will affect the moisture content of wood, so is very uneven distribution of moisture in wood.

The distributor that sells wood products should also test the moisture content of the products sold and master the quality status of the products sold. Choose the product quality good manufacturer, the manufacturer that pays attention to the product quality, can inspect the moisture content of its product.

The department that buys wood products with high quality, with the constant increase of professional knowledge,also pay more and more attention to wood product moisture content index. In the past, foreign buyers paid much attention to this indicator, and many of the wooden manufacturers who made export products and semi-finished products experienced this.