Plywood

Uncommon card · No. 91649

Plywood is a composite material manufactured from thin layers, or "plies", of wood veneer that have been stacked and glued together. It is an engineered wood from the family of manufactured boards, which include plywood, medium-density fibreboard (MDF), oriented strand board (OSB), and particle board (or chipboard). All plywoods bind resin and wood fibre sheets (cellulose cells are long, strong and thin) to form a composite material. The sheets of wood are stacked such that each layer has its grain set typically (see below) perpendicular to its adjacent layers. This alternation of the grain is called cross-graining and has several important benefits: it reduces the tendency of wood to split when nailed at the edges; it reduces thickness swelling and shrinkage, providing improved dimensional stability; and it makes the strength of the panel consistent across all directions. There is usually an odd number of plies, so that the sheet is balanced, that is, the surface layers have their grains...

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