Plywood is a remarkably strong composite typically made of thin veneers of wood peeled from logs (plies), that are sandwiched together with binders, pressed, and heated. The plies are laid at different angles, so the grain goes one way on one layer, then the next way on the next layer, and so on.
While wood tends to contract and expand with moisture across the grain, the alternating layers stifle that movement, making plywood more dimensionally stable than the average 2x4. The composition and materials of plywood make it resistant to warping, twisting, cracking, breaking, and shrinking. Three plies are the minimum, and generally the more plies, the better.
The grade refers to the physical appearance of the plywood.
Grade A: The face and back of the sheet is nearly free of defects, with a smooth, sanded surface and virtually no knots. Good for cabinet doors and furniture, the surface is meant to be seen (not covered with another material) and can be painted or stained. Other terms for
Grade B: Sanded smooth, but the face and back have a few defects, some of which have been repaired with patches or wood filler. Less costly than Grade A.
Grade C: Unsanded, with tight knots up to 1 ½ inches wide. There may be large areas that have been patched and filled. Good for subflooring or other applications where it will not be seen.
Grade D: Unsanded, with knot holes up to 2 ½ inches wide and liberal use of patches and filler and some unrepaired defects. Like Grade C, good for structural uses where it will not be seen.
When two grades are indicated, such as A/B, the A refers to the face and the B refers to the back.
ZMADTO Plywood Co.Ltd. is focus on construction plywood & wood formwork product. Our factory was established in 1993 and covers an area of 240,000 square meters with an average daily output of more 30,000 pcs plywood. Besides, the factory has more than 200 advanced equipment. After years of continuous development, it has become a leading company in the international wood formwork industry and exported to more than 20 countries around the world.
