Veneer is manufactured of wooden logs. Plywood is value added veneer. It is a manmade material made out of the wood of different trees, the most popular being Gurjan, Oak, Poplar & Eucalyptus.  However, plywoods in different regions are made from the nearest available timber.  The logs are chosen for their straightness and roundness. For the actual manufacturing process, thin veneers of wood are laid in alternating directions and bonded with glue into strong, sturdy sheets. The stack is then pressed in a hot press to form a rigid panel of varying thicknesses, and the final product is laminated. It is made from layers of thinly peeled wood that are glued together. Usually, plywood contains odd number of layers like 3, 5, 7, etc. this is done in order to achieve balanced construction. Each layer of Veneer (called a ply) is arranged so that the direction of the wood fibers or grain is placed at right angles to the layer next to it. After pressing, the plywood is conditioned and finished for packing, testing & dispatch.

Broadly speaking, there are three major types of plywood.

• Interior plywood (Commercial Plywood) is made by using glues that are non-water proof but are moisture resistant (Urea Formaldyhyde). These are used in interiors for making furniture, paneling & other interior works.
• Exterior plywood (Marine Plywood) is made using glue (Phynol Formaldyhyde) that is capable of water proof qualities & can withstanding delamination even if in contact with water or very high moisture.
• Shuttering Grade Plywood which are made by using water proof glue (Phynol Formaldyhyde) of higher grade & may also have a film face on both the faces for manufacturing of film faced shuttering plywood. These can be reused as formworks repeatedly in shuttering. High density plywood in this grade are also used as compreg for floorings, seats, etc.

Tips for Buying Plywood

- Thumb rule test for shuttering plywood : Soak the plywood in water at room temperature for 48 Hrs. minimum. Then dry in sunlight for 4 Hrs. It should not delaminate nor swell more than 4%. Or for instant testing, boil a 15” x 15” plywood piece in water for 60 minutes. It should not delaminate nor swell more than 6%.

- When you buy plywood, lay the sheet down on the ground. Avoid buying plywood that does not lie flat.

- Avoid plywood where a thick core is sheathed with thin face veneers.

- The piles should be parallel to one another with the alternate layers set at 90 degrees. This will avoid warping.

- To avoid warping, select plywood where the number of veneers on each side of the core layer must be equal in number and thickness.