Plywood plays a big role in any cabinetry or furniture project as it quickly forms boxes for cabinets or sides for furniture.
But this seemingly simple piece of wood has many complexities when it comes to understanding construction, grades, plies and thicknesses.
Woodworkers will also need to know how to properly cut plywood with tools like track saws, finishing techniques and storage. In this guide learn how to buy, cut and finish your next sheet of plywood with confidence.
What Is PLywood?
Plywood is a type of engineered wood that is made by gluing together thin layers of wood veneer, known as plies, with the grains of each layer rotated 90 degrees to each other. By using this type of construction a sheet of plywood has greater strength, stability, and resistance to warping than solid wood.
The number of plies in plywood can vary, but commonly plywood comes in 3-ply, 5-ply, 7-ply or 9-ply thicknesses.
- 3-plies are common in a 1/4″ thick plywood
- 5-plies are often used for construction and cabinetry for 1/2″ sheets
- 7 or 9-plies or more make up most 3/4″ plywood
Plywood is commonly made from softwoods for home construction, hardwoods for furniture and cabinetry. Additionally, plywood may be treated with chemicals when used in high moisture or for fire resistance.
Types of Plywood
There are several types of plywood available, some of which are used commonly in woodworking and others for home construction or marine use:
Softwood plywood. This type of plywood is made from softwood trees such as pine or spruce. It is commonly used for structural purposes such as roofing, flooring, and walls.
Hardwood plywood. Made from hardwood trees such as oak, birch, or maple and is known for its durability and strength. It is often used in furniture, cabinetry, and decorative applications.
Marine plywood. This plywood is specially treated to resist moisture and rot, making it ideal for use in boats and other outdoor applications.
Fire-retardant plywood. This type of plywood is treated with fire-retardant chemicals to meet safety regulations.
Structural plywood. Designed for use in construction applications where strength and durability are important. It is typically used for flooring, roofing, and walls.
Choosing the right type of plywood depends on factors such as strength, thickness, moisture resistance, and visual appearance.
How Plywood is Constructed
Plywood construction is complicated.
While lumber is processed into finished form by simple cutting and finishing, plywood requires extensive processing:
- Bark is removed
- Logs are cut to length
- Moisture content is increased
- Logs are peeled into thin ribbons (plies)
- Ribbons are cut to width (usually 48-inches)
- Sheets are stacked and dried
- Glue is applied and a press adheres plies together
- Paint or protectant is optionally applied
- Lastly, the plywood is cut to finished size
Solid Core vs. MDF Core Plywood
There is a debate amongst some woodworkers on medium density fiberboard (MDF) vs. solid core traditional plywood.
First, MDF is a mixture of fine wood particles that are glued and compressed into a sheet, offering a few advantages such as uniform thickness, no wood grain and a perfectly smooth finish.
Second, plywood cores almost always contain some defects in the softwood inner plies which have to be fixed and sanded. Making a solid core plywood slightly less uniform.
The comparison however comes down:
- MDF plywood is heavy as it has a higher density
- Next, solid core is lighter, but the finished face may be slightly lower quality
- Which, finally, leaves MDF with an advantage for finished face quality
While there is no right or wrong answer many woodworkers will opt for lighter weight or make a decision based on cost.
Understanding Finish Grades
Most woodworkers know that hardwood lumber that has a complex grading system based on quality of the wood.
And, since plywood is almost always visible in a project, plywood has a similar grading system.
Fortunately the grading system for plywood is fairly easy to understand and sheets are easy to inspect for quality:
- A-grade is defect free and most suitable for finished surfaces
- B-grade has some blemishes or knots and is typically used for construction
- C-grade may have larger knots and splits and is most often found in structural applications where appearance is not important
- D-grade is less common and has many defects. It is often used for temporary construction
Manufacturers such as Boise Cascade offer a “C-plugged” grade that has open defects plugged. Weyerhaeuser goes a step further and offers many grades including marine plywood.
Lastly, to conserve cost it is common to see a combination “A-B” grade where the face grade is finish quality and the reverse side is meant to be hidden.
Plywood Manufacturers
Some of the most popular plywood manufacturers include:
Georgia-Pacific: one of the world’s leading manufacturers of plywood for construction and industrial applications.
Weyerhaeuser: major producer of plywood, lumber and engineered wood.
Boise Cascade: producer of plywood and other wood products, with manufacturing facilities throughout North America.
Columbia Forest Products: produces PureBond, a line of high-quality plywood that is made using formaldehyde-free adhesives and sustainable wood sources.
Roseburg Forest Products: manufactures a range of decorative plywood products, including Medite line of medium-density fiberboard (MDF) and SkyBlend line of composite panels.
States Industries: leading manufacturer of hardwood plywood products including the popular ApplePly line of rotary cut hardwood veneer panels.
Brand Name Plywood
With a few manufacturers producing a branded plywood the first question is what makes that special?
Well, these plywoods are popular and trusted because of their construction process and quality controls. For example:
- PureBond is a formaldehyde-free plywood that uses soy-based construction to reduce toxicity of the finished wood.
- Mediate offers moisture resistance, formaldehyde-free and exterior-grade solutions with high quality controls
- ApplyPly is a high quality rotary cut hardwood that has a hardwood core and comes in a variety of US domestic as well as exotic veneers.
Where to Buy Hardwood Plywood
Trying to find quality hardwood plywood can be difficult.
While local box stores may have common species it’s often best to find a hardwood supplier who has both.
Where to look:
- Local hardwood suppliers (use our directory found here)
- Big box stores for common species like oak, maple or birch
- Some online stores like Forest2Home will ship smaller cuts
Just be sure to check the quality of the wood and ask on grades.
Best Ways To Cut Plywood
After purchasing plywood the first challenge is cutting it. Because of its size the two options for cabinet-grade plywood are either a table saw or track saws, circular saw or miter saw:
- Table saws excel at cutting large sheets into thinner rips of plywood. However, for cutting narrow plywood sheets a table saw can be extremely dangerous with risks of kick back. Lastly, a table saw requires awkward lifting and shifting of the plywood that can cause injury or mar the finish.
- Track saws have grown in popularity as they allow plywood to be cut with minimal lifting. And, thanks to advanced technology like cordless track saws are easy to handle and connect readily to dust extractors.
- Circular saws are best for rough, lower grades of construction grade plywood as they often rip and chip the surface of the plywood.
Storing Plywood
Much like storing hardwood off the floor and well supported the same goes for plywood.
Keys to storing plywood include:
- Never store directly on concrete as plywood will absorb moisture
- If stored flat support the plywood every 16-inches to prevent sagging and warping
- Storing on edge is common in space limited garages.
While wall-mounted lumber racks are common for hardwood they are generally only suitable for “ripped” plywood that is under 12-inches in width.
Finishing Plywood
Unlike hardwoods, plywood requires minimal preparation prior to finishing. However, proper grade selection, care in avoiding mars and ents, and light sanding is often required as preparation.
For hardwood plywood the following steps are important to properly finish hardwood:
- Inspect the full area of the plywood for imperfections
- Optionally fill any nail holes (most woodworkers will use Color Putty)
- Sand lightly with high count grits of sandpaper
- Shine a light on the finished area to find imperfections
- Apply either a penetrating wood finish and let dry, or a clear topcoat (following manufacturer directions)
Frequently Asked Questions
Is MDF or solid core better plywood?
While MDF is less expensive and has a higher finish quality due to its manufacturing process, solid core is generally preferred for its lighter weight and higher strength. But, on a large project the cost savings of MDF can make it a solid pick for indoor work. Conversely, for exterior projects solid core is a must as it will resist moisture when properly treated and used.
Which plywood is strongest?
The strongest plywood is typically a solid core plywood with the maximum thickness, hardwood cores and number of plies. Like all structural elements, thickness is generally indicative of strength. And in plywood an MDF core is inexpensive but doesn’t offer structural rigidity. Lastly, plies are criss-crossed bands of wood that are glued together to make a sheet. More plies means more thickness and fewer failure points.
What is CDX plywood used for?
CDX is a low face quality plywood that is used in construction projects where the wood will not be seen. Because its surface contains defects and blemishes it is not suitable for cabinetry where a smooth finish is required.
Summary
Plywood is a core part of many woodworking projects and understanding the various types of plywood, grades and how to best use it are important.
- About the Author
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Eric has been a professional woodworker for over thirty years and has worked in small cabinet shops making everything from kitchen cabinets to hand-made furniture. Now working from a home woodworking shop Eric is sharing his passion for woodworking, tool advice and how-to knowledge from his Minnesota-based woodshop.
