Finger joint boards are a type of wood product made by joining multiple wood boards together. Unlike traditional solid wood panels, the upper and lower sides of finger joint boards are not glued to a splint. Instead, the vertical boards use a zigzag-shaped joint that resembles the interlocking of two fingers, hence the name "finger joint board." This unique design allows for a stronger and more stable connection while reducing the need for excessive glue.
The application of finger joint boards is similar to that of regular wood boards, but they are much more environmentally friendly due to the reduced amount of adhesive used in their production. Traditional wood boards often require a significant amount of glue, which can release harmful chemicals over time. In contrast, finger joint boards typically use water-based polyvinyl acetate (PVA) glue, which is non-toxic, odorless, and safe even when it decomposes into acetic acid.
Finger joint boards come in various thicknesses, including 12mm, 14mm, 16mm, 20mm, and even up to 36mm for thicker applications. They are available in two main types: with knots and without knots. Boards without knots tend to look cleaner and more refined, making them a popular choice for furniture and interior design.
One simple way to assess the quality of a finger joint board is to examine the core material's annual rings. Fir is commonly used, and the more pronounced the annual rings, the better the quality of the wood. Larger rings indicate a longer growth period, resulting in a stronger and more durable board.
In addition to fir, eucalyptus finger joint boards are also available on the market. These are often used for closet shelves and have natural anti-moth properties, eliminating the need for chemical mothballs. However, they are generally more expensive and less widely available.
Finger joint boards can be classified into two types based on the visibility of the joints: bright teeth and dark teeth. Dark teeth are considered superior because they are less likely to show unevenness after painting. While dark teeth are harder to process, they offer a smoother finish and better durability. The hardness of the wood also plays a role—harder woods tend to deform less and display more attractive grain patterns.
Compared to solid wood boards, finger joint boards are not entirely solid wood, but rather a combination of smaller wood pieces joined together. This makes them more stable and less prone to warping or cracking. Solid wood boards, on the other hand, are made from wood-based panels, which may contain more adhesives and formaldehyde.
When it comes to environmental friendliness, the key factor is the level of formaldehyde emissions. Both finger joint boards and wood boards can meet E1 standards (formaldehyde emission below 1.5mg/L). However, finger joint boards typically use less glue, making it easier to maintain eco-friendly standards. Boards with splints may still release formaldehyde, but finger joint boards do not have splints, making them a safer and greener option.
To produce a finger joint board, the raw materials go through several steps: cutting logs into shorter pieces, slicing them into slats, drying and modifying them in special equipment, sorting by color and defects, preliminary planing, shaping, assembling, further drying, sanding, and finishing. By breaking down the wood into smaller units and recombining them, the final product can achieve improved strength, stability, and uniformity. Boards made from larger units tend to be stronger, while those made from smaller units offer better homogeneity.
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