One of the main reasons for using plywood is stability; however, low-quality sheets of plywood can be anything but stable. When it comes to stability, the inner core is highly significant. It affects both performance and appearance. Thinner face veneers offer less support, making the core an even more significant part of the equation. As you search for plywood to meet your needs, one thing you need to consider is core.
Introduction to Veneer Core
The most commonly used core type, veneer core plywood is comprised of thin veneers ranging from 2 to 6.5 mm thick. The veneers are laid out in alternating grain patterns, creating an extremely stable substrate. Typically, the more layers used, the more stable the product becomes. (Glue quality and application are also factors.) Gaps between veneer layers are basically unavoidable, and the quantity and size of those gaps largely affects the sheet’s grade.
Appreciated for its superior screw-holding capacity, veneer core plywood is readily available due to the species from which it’s made. Speaking of species, the species used also impacts the performance of veneer core plywood. Often, a mill’s location determines the species it uses for its veneer core plywood, so consider that when you’re looking for a manufacturer.
Veneer Core Species Overview
Fir is the species used most commonly on the U.S. West Coast for veneer core plywood. With its weather resistance and high stability, Fir Core plywood has excellent screw-holding ability. Thanks to its relative softness, any inconsistencies will typically even out during the compression stage of the manufacturing process.
Poplar Core plywood is typically used by Eastern manufacturers in the United States. Heavier and harder than Fir, Poplar offers a stable core but lacks the weather-resistant quality of Fir; as a result, it’s not the ideal choice for exterior projects. Poplar is also harder than Fir, a characteristic that keeps it from compressing. Any knots and voids in the core will become apparent on the veneer face. Without proper drying, Poplar cores can easily delaminate.
Found in Northern and Western regions of the United States, Aspen Core plywood is less dense than Fir but otherwise similar to it. The result is a lighter core that’s soft enough to compress and offer a consistent face.
Maple and Birch Core plywood is considered a high-end product. It typically consists of a significantly greater number of plies than Fir or Poplar Core plywood. These harder species combine with thinner, more plentiful layers to create an incredibly stable product with no voids, whatsoever. The edge strength is also remarkable, offering an attractive appearance without risk of splintering. Maple Core is sometimes referred to as Apple Core; both Maple and Birch offer extremely dense cores. Ideal for decorative projects with exposed edges, Maple and Birch Core Plywood is considered the best of the best.
