Plywood is used in many applications that need high-quality,
high-strength sheet material. Quality in this context means resistance to cracking,
breaking, and shrinkage, twisting and warping. In India, plywood is more commonly called
"Kitply" after a leading brand which pioneered the concept of waterproof plywood in the
Plywood is a sheet material manufactured from thin layers or
"plies" of wood veneer that are glued together with adjacent layers having their wood
grain rotated up to 90 degrees to one another. It is an engineered wood from the family
of manufactured boards which includes medium-density fibreboard (MDF) and particle board
All plywoods bind resin and wood fibre sheets (cellulose cells
are long, strong and thin) to form a composite material. This alternation of the grain
is called cross-graining and has several important benefits :
it reduces the tendency of wood to split when nailed at the edges, it reduces expansion
and shrinkage, providing improved dimensional stability and it makes the strength of the
panel consistent across all directions. There is usually an odd number of plies, so that
the sheet is balanced—this reduces warping. Because plywood is bonded with grains
running against one another and with an odd number of composite parts, it is very hard
to bend it perpendicular to the grain direction of the surface ply.
Softwood Plywood :
Softwood panel is usually made either of cedar, Douglas fir or
spruce, pine, and fir (collectively known as spruce-pine-fir or SPF) or redwood and is
typically used for construction and industrial purposes.The most common dimension is 1.2
by 2.4 metres (3 ft 11 in × 7 ft 10 in) or the slightly larger imperial dimension of 4
feet × 8 feet. Plies vary in thickness from 1.4 mm to 4.3 mm .
Hardwood Plywood :
Hardwood plywood is made out of wood from angiosperm trees and
used for demanding end uses. Hardwood plywood is characterized by its excellent
strength, stiffness and resistance to creep. It has a high planar shear strength and
impact resistance, which make it especially suitable for heavy-duty floor and wall
Tropical Plywood :
Tropical plywood is made of mixed species of tropical wood.
Originally from the Asian region, it is now also manufactured in African and South
American countries. Tropical plywood is superior to softwood plywood due to its density,
strength, evenness of layers, and high quality. It is usually sold at a premium in many
markets if manufactured with high standards.
Aircraft Plywood :
High-strength plywood also known as aircraft plywood, is made
from mahogany and/or birch, and uses adhesives with increased resistance to heat and
humidity. It was used for several World War II fighter aircraft. Although the
British-built Mosquito bomber, nicknamed "The Wooden Wonder", was constructed of a
plywood monologue, this was formed in moulds from individual veneers of birch, balsa and
birch, (citation needed) rather than machined from pre-laminated plywood sheets.
Flexible Plywood :
Flexible plywood is designed for making curved parts, a practice
which dates back to the 1850s in furniture making. Aircraft grade plywood, often Baltic
birch, is made from 3 plies of birch, as thin as 1/16" thick in total, and is extremely
strong and light. At 3/8" thick, mahogany 3-ply "wiggle Board" or "Bendy Board" come in
4' x 8' sheets with a very thin cross grain central ply and two thicker exterior plies,
either long grain on the sheet, or cross grain.