The process requirements for plywood are very high. Not only does it require sufficient space for the wood to have enough time to adapt and dry naturally, but it also requires strict drying process control through a drying kiln. Especially after the national mandatory implementation of limits on harmful substances in decoration and renovation, the adhesives used for plywood must be improved, which alone increases the cost significantly, and the price of raw materials is also constantly rising. Therefore, due to cost constraints, plywood priced below 80 yuan should not be purchased. Blindly pursuing cheap prices can harm human health. Many merchants use various methods to deceive consumers in order to make a profit. Therefore, when purchasing, the following points should be noted:
(1) The quality grades of plywood are divided into superior, first-class, and qualified products. Before leaving the factory, each plywood should have an indelible ink mark on the lower right corner of the back of each board, indicating the product category, grade, manufacturer code, and inspector code; the category mark should indicate indoor or outdoor. If this information is missing or unclear, consumers should be wary.
(2) Visual inspection: Select boards with a smooth surface and few knots or peeling. Observe whether the board surface is warped, bent, bulging, or dented. Observe whether there is any glue or putty filling around the board. Check whether the core strips are evenly and neatly arranged; the smaller the gaps, the better. The width of the core should not exceed 2.5 times the thickness, otherwise it is prone to deformation.
(3) Touch test: Spread your palm and gently smooth the surface of the core board. If you feel any rough edges, it indicates poor quality.
(4) Lift one side of the plywood with both hands and shake it up and down. Listen for any sound of wood stretching or breaking. If there is, it indicates large internal gaps and many voids. High-quality plywood should have a sense of wholeness and weight.
(5) After sawing it open from the side, observe whether the quality of the wood in the core is even and neat, whether there is rot, breakage, wormholes, etc., and whether the gaps between the solid wood strips are large.
(6) Put your nose close to the cut surface of the plywood and smell for any strong, pungent odor. If the plywood has a pleasant wood scent, it indicates low formaldehyde release; if the odor is pungent, it indicates high formaldehyde release, and you should not buy it.
(7) After purchasing, carefully check the plywood being loaded onto the vehicle to ensure it matches the sample shown at the time of sale, to prevent unscrupulous merchants from substituting inferior products.
(8) Be wary of merchants intentionally blurring the lines between E1 and E2 grades to sell counterfeit or substandard products. Plywood is classified into E1 and E2 grades based on its harmful substance limits, with formaldehyde being the primary harmful substance. Only E1 grade plywood should be used for home decoration and renovation. Even if an E2 grade plywood product is qualified, its formaldehyde content may be more than three times higher than that of E1 grade plywood.
(9) Request the plywood testing report and quality inspection certificate from the merchant. Plywood with a formaldehyde content of no more than 1.5 mg/L can be used directly indoors. However, plywood with a formaldehyde content of no more than 5 mg/L must undergo a surface treatment before it is allowed to be used indoors. Therefore, when purchasing, be sure to ask whether it meets the national standards for indoor decoration materials and make sure it is noted on the invoice.