Wikipedia meaning of plywood means thin layers of plies of wood skins that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another.
While the layers of plies are glued together pressure is applied to bind them together. This pressure could be applied hot or cold. In hot pressure process hydraulic press is employed to press and temperature may range from 150 o c to 260 o c. For cold press it could be pressed at room temperature only. Pressure applied for cold press may vary from 0.70 to 140 N/mm.
Plywood is available in different form and different thickness and size. Thickness available may vary 4mm to 25mm depending on usage. Various thickness of plywood is used for furniture or other construction purpose. There are different grades of plywood available in India.
Following grades of plywood are available in India -
Plywoods In India
MR grade plywood
BWR grade plywood (IS 710 Indian standard)
BWP grade plywood (IS 710)
Advantages of MDF are - that it is generally cheaper than plywood. MDF is not as hard as plywood and can sag under heavy weight. MDF does not handle moisture very well. MDF is not as hard as plywood and can be damaged easily when roughly handled. It is not as stiff as plywood.
BWP / BWR grade plywood
The Indian standard quality specification for marine types of plywood are described in the standard document IS 710.
Standard sheet sizes1) 6’ x 4’
2) 8’ x 4’
Standard thickness of plywood1) Marine – 4mm , 6mm, 9mm, 12mm & 19mm.
2) Commercial – 4mm, 6mm, 8mm, 12mm & 18mm