Plywood thicknesses depend on the number of thin wood layers combined together with an adhesive. Each of the wooden ply layers is stacked in such a way so that the grain runs at right angles. Layers are thus bonded adjacently to lower shrinkage and improve strength of the finished piece. These flat sheets of plywood layers are pressed together and used during building construction. Plywood pieces of other forms may be compounded to be used for making boats, furniture, and aircraft.
Plywood was used as early as the 1500 B.C for construction use by Egyptian craftsmen. In fact, the earliest signs of such dark ebony wooden texture can be found in the tombs of kings at that time. Later, Romans and Greeks also adopted the art of plywood use to produce decorative object pieces and fine furniture items. This art of applying plywood for furniture making came to be known as veneering. Plywood pieces called vaneers also became popular for creating durable furniture and other decorative pieces made to long.
Vaneers when glued and laminated to form a thicker material is now known as plywood. However, it wasn't until the late 1800s when plywood was first used for commercial purposes. Gradually sheets of laminated vaneers were used to produce multiple plywood sheets that found application in not just doors and furniture, but even in buses, railroad cars, and airplanes. At this time, plywood sheets that are actually wooden sheets bonded or pasted together were criticized for their make, but given the varying thicknesses that could be achieved, it came to be known as plywood.
The first sheets for commercial purpose were applied in general building material. With years of advanced adhesive use and with newer production methods, plywood attained usage in various industries as well. With increased application and multiple usages laminated vaneers or plywood replaced lumber and thus emerged as a massive multi-million dollar industry worldwide. Plywood thicknesses of varying sizes started to be induced into building harder material laminates and provided considerable efficiency in terms of functionality, style, and durability.
Plywood outer layers are known as the face and back respectively. The outside surface which can be seen is the face while the inside that remains hidden with plying is the back. The central layer is known as the core and five or more layers together are known as cross bands. Manufactured from softwood and hardwood or both materials combined together come in various wooden types such as mahogany, ash, teak, maple, oak, cedar, pine, redwood, and spruce. Bonded together with adhesives such as phenol-formaldehyde resin, soybean protein, urea formaldehyde resin and blood protein these are commonly used in different sectors like transportation, construction, and agricultural industries.
Plywood sheets range in thicknesses from 1.6mm to 76mm. The most common are in the 6.4mm to 19.0mm range. Core, face and back and crossbands are of varying thicknesses each of these should balance the center. The material face and back is of equal thickness as well as the top and bottom. Common plywood sheet sizes in building construction are 1.2m to 2.4m long with varying length increments from 8ft to 12ft. This determines the pricing of the plywood material depending on the texture and thickness. Boat building compound curves require much larger sheets. Plywood sheets are assembled by layering and gluing together in hot press. Rough sheets are passed through set of saws for the final trim. The plywood grade varies from one type to another and different industries have their own standards.