It is interesting to know how plywood or engineered wood is made. Logs of wood are peeled into thin layers known as veneers. These veneers are laid side by side and one on top of another with high quality adhesive to hold the layers together. The quality of plywood depends on the timber or type of wood, the adhesive used to glue the veneers and the manufacturing process adopted by all the renowned commercial plywood manufacturers in India.
Most common types of plywood are made from raw softwood timber. Quality plywood sheets are manufactured using seasoned, kiln dried hardwoods. This makes a difference to the strength and durability of the plywood. The other factor is the adhesive. General purpose commercial plywood uses a standard adhesive whereas expensive, durable, water-proof and the best quality plywood in India may use better quality polymer based or phenolic resin adhesives cured under temperature and pressure.
One type that is commonly used for a variety of purposes is the MDF type of medium density plywood with a core of hardwood fiber. Manufacturers use sawdust and peeling instead of veneers to manufacture MDF board. MDF is uniformly consistent and does not have any blisters or gaps. MDF board is easy to cut lengthwise or crosscut.
There is another variety termed MDO and HDO or medium and high density overlay plywood. It is a mix of softwood veneers overlaid with fiber, a mix of MDF and plywood. The surface can exhibit wood patterns and it is more durable while being lighter than plain MDF board.
A third type is the veneer core hardwood plywood. The inner veneers are made of common hardwood while the surface veneer is made of high quality hardwood with a typical wood grain pattern. It can be cut in any pattern and it is stronger than commercial plywood. This type of plywood does not require a laminate to be glued since the surface can be finished with varnish for a natural wood grain appearance.
Though not strictly plywood, there is the blockboard, also known as lumber core plywood. Wood is cut into uniform thicknesses and then glued or held together with embedded corrugated shaped steel pins and overlaid with veneer. Blockboard is less expensive than plywood and is ideal for doors.
Finally, there is the particle board core type plywood in which coarse particles of wood are bonded together with glue. The strength is less but it can be cut into shapes and overlaid with laminates to make low cost furniture. There are commercial plywood manufacturers in India having formidable reputation both India and abroad for their high quality products. Some of these companies have been in the market for around 60 years. It is necessary for the buyer to be well aware of the type of the product along with the company manufacturing it.