If we carefully observe some high-end solid wood furniture, especially mahogany furniture, we will find that there is often a gap that is not wide or narrow on the side of the furniture panel.

This gap is called expansion joint or contraction joint, it is not caused by mistakes in furniture design and manufacture. On the contrary, expansion joints are intentionally smart"idea". Its existence has played a huge role in preventing the physical characteristics of wood "heat expansion and contraction" and improving the service life of solid wood furniture.

Expansion joint is a traditional processing technology of Chinese classical furniture. Anyone who knows classical furniture knows that a piece of pure classical furniture will inevitably retain the excellent craftsmanship of traditional furniture——The tenon-and-mortise structure does not use an iron nail, and the components of the furniture are assembled by the clever combination of tenon and mortise.

In spring and winter, the air is dry. When artificially drying wood to make furniture, it is generally necessary to leave expansion joints. Otherwise, the wet side will swell after the arrival of summer. The expansion joint is to prevent the furniture frame or corner tenon when the wood shrinks or expands due to the influence of the external environment, resulting in the looseness of the furniture components and the normal use.

Conversely, dried materials in winter. Come again after the New Year, although it can be fitted tightly. But the season when the rainy season is coming will definitely burst. Unless the furniture is made in a place with little change in the four seasons, it is used locally. There are also different materials with different stresses. The changes of R. chinensis and Huanghua pear are the smallest, and the changes of contraction of large leaves and red acid are large.

In order to reduce the deformation of the wood, the mahogany has a strict drying process before it is made into furniture, and some may be baked for more than a month. In order to control the quality of regulated manufacturers, the moisture content of products sold to different regions is also different.

Solid wood furniture should have expansion joints to contain wood"Heat expansion and contraction" to extend life.

(1) Expansion joint is to prevent the frame or corner of the furniture from cracking when the wood shrinks or expands due to the influence of the external environment, resulting in the looseness of the furniture components and the normal use.

(2) In order to reduce the deformation of the wood, there is a strict drying process before the wood is made into furniture, and some may be baked for more than a month. In order to control the quality of regulated manufacturers, the moisture content of products sold to different regions is also different. Even so, in order to prevent furniture deformation, expansion joints must be reserved.

Expansion joint size

Solid wood furniture, especially the expansion joints of classic mahogany furniture, are reserved specifically for adapting to different environments. The purpose is to not crack the frame or corners of the furniture.

The size of the expansion joint is very important, and the width is determined according to the specific gravity of the wood and the climate characteristics of the area where the furniture is ultimately used. The width of the expansion joint is generally0.3-0.5Within cm, more than0.5Cm is ugly, if the panel is not too wide, more than0.5No need at all. The expansion joint is too wide, generally the wood is not dry well when making furniture.

The need for expansion joints

Before the wood is made into furniture, there is a strict drying process, and some may be baked for more than a month to reduce deformation. In order to control the quality of regulated manufacturers, the moisture content of products sold to different regions is also different. Even so, in order to prevent furniture deformation, expansion joints must be reserved.

The longitudinal shrinkage of the wood is not large, generally no expansion joints are required at both ends. Some manufacturers leave seams on all sides, so it looks relatively beautiful.

There are also some manufacturers that do not leave expansion joints for furniture, but not leaving does not necessarily mean that there is no, because manufacturers are not absolutely sure about the drying of wood. Generally, the moisture content of wood is higher than the moisture content of air, so even if there is no expansion joint in the production, furniture production There will also be seams after finishing, and a considerable part of furniture will have seams in both wet and dry seasons, but the size is different.

In areas where there is a large difference in dry and wet environments throughout the year, expansion joints are a must. The air humidity in the rainy season is high. Although the wood is artificially dried, the wood will still absorb moisture during the furniture manufacturing process, and the volume will increase. Generally, there is no need to leave expansion joints. The expansion joints will also appear when the weather is dry in winter; When making furniture by artificially drying wood, it is generally necessary to leave expansion joints, otherwise, the wet side will swell after the arrival of wet summer.

Other considerations

If it is solid wood furniture, there will be no expansion joints on the surface of the desktop and board. If there are, it may be the following two reasons: First, the desktop board is a frame structure, and second, it is caused by other special processes or materials on the desktop. Among them, the frame structure is the most commonly used board and wood combined furniture, we should pay attention to distinguish.

Finally, remind everyone that the expansion joints are made of solid wood furniture"Self-protection system", there is no need to worry when the size is uneven, most of them will return to their original appearance after the season changes.