First, blockboard
1. Concept: Blockboard (commonly known as large core board, wood board) is a plywood with solid wood core. Its vertical direction (different from core sheet) is resistant to bending and pressure, but the lateral bending strength is high. Most of the market is now solid, glued, double-sided sanding, five-layer blockboard, size is 1220 mm × 2440mm.
2. Characteristics: The blockboard has good clamping force, high strength, good quality, sound absorption, heat insulation, etc., and the water content is not high, between 10% and 13%, the processing is simple and the most widely used.
Blockboard is more stable than solid wood, but it is afraid of moisture. It should be avoided in the kitchen.
The processing technology of blockboard is divided into two types: hand-stitching is to manually insert the wood strip into the splint. The strip is subjected to poor pressing force and cannot be cut and processed. It is only suitable for partial decoration. Such as making a solid wood floor cushion board. The plate of the machine is subjected to a large pressing force, the gap is extremely small, the splicing is flat, the bearing capacity is uniform, and the long-term use is not easily deformed. The price of a good blockboard is between 70-140 yuan, and the difference between 40-60 yuan. The inner core of blockboard has many kinds of materials, such as poplar, birch, pine, paulownia, etc. Among them, poplar and birch are the best, the texture is dense, the wood is not soft and hard, the nailing force is strong, and it is not easy to be deformed. The texture of Paulownia is soft, the water absorption is large, and it is not easy to dry. After the long-term use of water is evaporated, the plate is easy to dry and deform. The hard wood is hard, not easy to press, the splicing structure is not good, the nail holding power is not bad, and the deformation coefficient is also large.
3. Uses: furniture, doors and windows and sets, partitions, false walls, heating covers, curtain boxes, etc.
4. Choice: The surface of the blockboard should be flat, without warping, deformation, no blistering or dent; the core strips are evenly arranged, the gap is small, the core strip has no decay, breakage, wormholes, thrift and so on. Some blockboards cut corners, and the gap between the solid wood strips is large. If nails are nailed in the gap, there is basically no nail holding force. Consumers can look at the sun when they choose, and the gap between the solid wood strips will be white. If the glue strength of the blockboard is not good, it will have a "å±å±" opening sound when it is self-financing. If the large core board emits a fragrant wood smell, it means that the formaldehyde emission is less; if the smell is pungent, it means that the formaldehyde is released more.
The quality of blockboard is very different and should be carefully checked when purchasing. First of all, see if the core material is dense, whether there are obvious seams and decaying wood strips, whether there are obvious seams and decaying wood strips, there may be eggs in the decaying wood strips, and insects will occur in the future; The phenomenon of filling the putty, this phenomenon is generally to compensate for the internal cracks or voids; then it is to use the sharp-mouthed instrument to strike the surface of the board, to hear whether the sound is very different, if the sound changes, there is a cavity inside the board. These phenomena will weaken the overall bearing capacity of the board, and the uneven long-term stress will cause the sheet structure to be distorted and deformed, which will affect the appearance and use effect.
Second, plywood
1. Concept: Plywood is made of three or more layers of solid wood veneer or thin-plate adhesive. It is commonly used with three plywood, five plywood, nine plywood and twelve plywood (commonly known as plywood, five plywood, Nine PCT, 12 PCT).
2. Characteristics: good structural strength and good stability. The plywood has a large amount of glue, and it must be edge-sealed during construction to reduce pollution.
3. Uses: Plywood is mainly used for various wood products such as the bottom plate of decorative panels and the backboard of panel furniture.
4. Choice: Select the plywood mainly to see its formaldehyde emission and bonding strength. If the gluing strength of the plywood is not good, it is easy to fall apart. When selecting, pay attention to whether the nominal thickness of the plywood matches the actual thickness.
Pay attention to the following points when choosing plywood:
1 plywood has the difference between front and back. When selecting, the plywood should have a clear wood grain, a smooth and smooth front surface, and no roughness.
2 Plywood should not be damaged, bruised, bruised, and smashed.
3 glue full board without degumming.
4 Some plywood is made by sticking two veneers of different textures together, so in the selection, it should be noted that the splint joints should be tight and there is no unevenness.
5 When selecting plywood, you should pay attention to the selection of non-dispersed plywood. If the sound is brittle when the hands are knocked on various parts of the plywood, the quality is proved to be good. If the sound is boring, it means that the plywood has been discolored.
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