Written by: Michael Richardson - Sales & Marketing
When selecting hardwood plywood for a project, there are
many choices that we all face. What species of veneer do we want, what type of
cut, what grade?… But one question that is sometimes overlooked is what
substrate works best?
Almost all hardwood plywood is available in several
varieties of core, but not all core types are the same. There are three common
categories of substrates: Veneer Cores, Composite Cores and Hybrids or
“Combination Cores.” Although each may be different from the other, they all
have specific benefits that make them the perfect choice for various
constructions.
Veneer Cores are comprised of an odd number of
wood veneers laminated in alternating grain directions to achieve the desired
panel thickness. A thin panel may consist of one core veneer, while a very
thick panel might have 23 veneers. Core veneers may be softwood or hardwood and
the grades of the wood can vary significantly.
Veneer core panels are light in weight, high in dimensional
stability and bending strength, and hold screws better than other substrates.
They are less uniform in surface flatness and thickness, and edges are
generally not attractive. Veneer core panels are great choices for cabinets due
to their lower weight and higher screwholding properties.
ApplePly® by States Industries, is a
type of veneer core product constructed from 1/16” Birch innerplies
using a two-step lamination process. The innerplies are first assembled into a
core blank and size sanded to a metered tolerance before being overlaid with
selected face and back veneers. This process insures a solid, smooth, and flat
product that eliminates the telegraphing of imperfections in the core. The all hardwood
construction machines without tearout or burn. Because of its machinability,
ApplePly® is often substituted for solid wood. ApplePly® has long been a
preferred product for architects, designers, and woodworkers alike for its
solid construction and attractive edge. For more information on ApplePly®,
visit our website: http://www.appleply.com
Composite Cores used in hardwood plywood
construction are typically made of particleboard or medium density fiberboard
(MDF). Both particleboard and MDF are made from small particles of wood
compressed with an adhesive to create a solid, flat panel of uniform thickness.
Although similarly made, there are differences between the two.
Particleboard is perhaps the least expensive core for
hardwood plywood because its particles are less refined than MDF, yet it is
perfect for many applications due to its flatness and uniform thickness.
Medium Density Fiberboard is manufactured from highly
refined wood particles into an extremely dense panel that in addition to being
very smooth and uniform in thickness, will machine more like solid wood than
either particleboard and veneer cores.
Composite cores are valued for their flat, smooth surfaces
and tight tolerances, as well as their relatively low costs. They are also
heavy, can spread or shrink as much as 3%, and are not as strong as veneer
cores.
Combination Cores are a hybrid of veneer and
composites that take advantage of the best properties of both by using veneers
to build the center portion and thin MDF on the outer layer of a core, directly
under the face and back veneers.
The veneer centers are light, strong, and dimensionally
stable and hold screws well; the MDF surfaces provide a smooth, flat and solid
support for the decorative face and back veneers.
Combination Cores are popular with case good manufacturers
for their ability to support high value, very thin face and back veneers. This
is especially important in geographic areas with very low humidity which can
cause veneers to split or “check”. Combination Core's low weight, strength, and ability to
hold fasteners exceed that composite cores. While their flatness, smoothness and
tight tolerances exceed that of veneer cores.
How important is the substrate to you when buying hardwood
plywood? Do you have a preference for your specific projects?
