Industrial Grade Particleboard

Sometimes referenced as composite core, is made of wood particles of various sizes that are bonded together with a synthetic resin or binder under heat and pressure.

Medium Density Industrial Particleboard is used in the broadest applications of architectural woodwork. It is especially well suited as a core for veneers and decorative laminates.When used as panels without surface plies, the product is referred to as particleboard.

When used as an inner core with outer wood veneers, the panel is referred to as particle core plywood.Industrial particleboard is commercially classified by “density,” which is measured by the weight per cubic foot of the panel product.

• Medium Density (M series) = generally between 40-50 pounds per ft3 (640-800 kg per m3)
• High Density (H series) = generally above 50 pounds per ft3 (800 kg per m3)

Moisture Resistant Particleboard

Some Medium Density Industrial Particleboard is bonded with resins more resistant to swelling when exposed to moisture. The most common grades are ANSI 208.1-1999 Type M-2-Exterior Glue and M-3-Exterior Glue. Availability to the architectural woodworker is limited in some markets.

Fire-retardant Particleboard

Some Medium Density Industrial Particleboard has been treated during manufacture to carry a UL stamp for Class I fire rating (Flame spread 20, Smoke developed 450). This material is of-ten used as a substrate for paneling requiring a Class I rating. Fire-retardant Medium Density Fiberboard is also available in some markets.

Medium Density Fiberboard (MDF)

Wood particles reduced to fibers in a moderate pressure steam vessel, combined with resin, and bonded together under heat and pressure. Due to the finer texture of the fibers used in manufacturing Medium Density Fiberboard (MDF) it is smoother than Medium Density Particleboard. The uniform texture and density of the fibers create a homogenous panel that is very useful as a substrate for paint, thin overlay materials, veneers and decorative laminates. MDF is among the most stable of the mat-formed panel products. When used as an inner core with outer wood veneers, the panel is referred to as MDF core plywood.

Moisture Resistant MDF

Some MDF is made to meet the ANSI 208.2-(latest edition)reduced thickness swell criteria.

Veneer Core

Three of more layers (plies) of wood veneers pressed and glued into a single sheet. What many think of as traditional "plywood," a panel made up of alternating layers of thin veneers, is called veneer core. Adhesive is placed between the veneer layers, and the panels are assembled under heat and pressure until the adhesive is set. The two outside layers of veneer are often selected for species, grain, and appearance; and are called the "face veneers."

Combination

A balanced hybrid blend of veneer and composition core materials offering some of the properties of both. Typically these cores have internal layers which are constructed of three or five plies of veneer or a center layer of wafer board (randomly oriented wafers) or other wood fiber which are sandwiched between thin laminations of a composite product like MDF, particleboard, hardboard, etc. Typically these products result in stronger, lighter weight, dimensionally stable panels with increased screw holding ability, and superior surface flatness.

Hardboard

Hardboard is defined as inter felted fibers consolidated under heat and pressure to a density of 500 kg per M3 (31 pounds per cubic foot) or greater.Often used for casework backs, drawer bottoms, and divider panels, hardboard is available with either one side (S1S) or two sides (S2S) smooth. There are typically two types of hardboard core used by architectural woodworkers: Standard (untempered) and Tempered, which is standard hardboard subjected to a curing treatment increasing its stiffness, hardness, and weight

Lumber

The center ply, called the "core" is composed of strips of lumber edge glued into a solid slab. This type is usually ply, 3/4" (19 mm) thick, but other thickness from 1/2" (12.7 mm) to 1-1/8" (28.6 mm) are manufactured for special uses. There are three main types:

• Staved - is where the core strips are random length and butt joined.
• Full Length - is where the core strips are one piece in length.
• Banded - is where the outside strips run full length and the others are random length. Banding may be the same species of lumber as the rest of the core, but it is usually matched to the face and might include all four edges. Banded plywood is typically produced for special uses, such as furniture, desk tops, and cabinet doors.

Agrifiber

Panel products made from straw and similar fiber.

Forming (Bendable)

Assembled and/or machined cores made of hardboard, veneer, particleboard and/or MDF for radius work are manufactured under various trade names. When used for freestanding work these Forming Cores must be a balanced panel but if bound (restrained) the panel is not required to be balanced

Solid Phenolic (SP)

A composite of solid phenolic resins molded with a homogeneous core of organic fiber reinforced phenolic and one or more integrally cured surfaces of compatible thermoset nonabsorbent resins. SP has seen some use in recent years as wall surfacing, casework parts, and countertops

Other Panel Material

Shall meet the minimum performance characteristics of ANSI A208.1, ANSI A208.2 or ANSI/HPVAHP-1(latest edition) standards.

Engineered Wood/Panel

Is a general term used to describe any wood or plant fiber composite panel. Such products as Particleboard, MDF, SCL and LVL are described as an engineered wood or plant fiber. Typically they are made from wood or plant fiber or wood pieces and have specific esthetic and physical attributes.