Cabinet Grade Plywood
The term Cabinet Grade Plywood is a general term, applied to any hardwood plywood which can be used in the manufacture of cabinets or furniture cabinetry. While this can refer to specific hardwoods, such as oak, maple and cherry, we also find plywood that is listed only as “cabinet grade,” without the specific hardwood veneer being mentioned. In these cases, it is typically referring to lesser expensive hardwoods, such as birch or some types of mahogany.
What qualifies plywood as being considered “cabinet grade” is the quality of the veneer surfaces; nothing more. These faces are graded differently than softwood plywood, with a grading being provided for both faces. The “good” or visible face is letter graded while the back face is number graded.
The quality of the veneer and type of wood it is made of are really the only thing that defines a particular piece of plywood as being “cabinet grade” rather than structural grade. Due to the cost difference, you’d never want to use cabinet grade plywood for structural work.
Visible Face Grades:
- AA – Good or good sequence
- A – Good
- B – Good, sliced B, RC sound
- C – Rotary cut solid
Back Face Grades:
- Sound, same species, specifically cut
- Solid, same species, specifically cut
- Rotary Grain
- Reject Back
Typically, you’ll see the plywood marked in a way that indicates both the front and back of the sheet, such as A2, which indicates an A grade on the face side and a 2 grade on the back side. Grades A1 and A2 or above are considered good for staining and varnishing. Grades B3 and below are paint grade plywood products.
Not all veneers used for plywood faces are created equal. The quality of the veneer, its thickness and how it is cut are all things you need to be aware of. High quality cabinet grade plywood will usually have face veneers that are about 1/40” of an inch thick. While that isn’t much, it’s much better than the lower grades, which will have face veneers that are only 1/100” thick. Great care must be taken when sanding this sort of veneer, as it is easy to sand right through it.
Another important consideration is how the face veneer is cut. It can either be rotary cut or plain-sliced. This will greatly affect the appearance.
Rotary cut plywood is cut on a huge lathe. A log is placed on the lathe and the wood peeled off in one long veneer sheet, as wide as the log and as long as it can be. That is then cut up and used for the core or face veneer for plywood.
This is why common structural plywood doesn’t have much of a grain pattern. That pattern comes from cutting across the log’s rings, but this means of cutting rarely crosses the rings. All structural grade plywood is made this way, as well as the core veneers of hardwood plywood. Face grade C and back grade 3 are rotary cut. They are only used for applications where the finished item will be painted.
Plain-sliced veneer is cut in the same manner as boards, cutting across the tree’s rings, which allows the gain pattern to show. It can be live sawn, plain sawn or quarter sawn and is much more attractive, providing the contrast in grain color that make many hardwoods attractive. For furniture and fine cabinetry, where the plywood is being stained and varnished, hardwood plywood with plain-sliced veneer is preferred.
The best cabinet grade plywood won’t only use plain-sliced veneer for the face side, but that veneer will be book matched, providing the most attractive gain patterns. Careful project planning and layout for cutting is necessary when using these grades of plywood, so as to get the maximum benefit out of the book matched grain.
Cabinet Grade Plywood Thickness
Cabinet grade plywood comes in thickness ranging from 1/4” up to 3/4”. Generally speaking, 3/4” thick plywood is used the most for cabinetwork, although thinner plywood may be used for furniture, including such things as dressers. The thicker plywood is used for cabinets to provide stiffness and strength. Cabinets are expected to last for a long time, so it might seem that the plywood thicknesses called for in project plans are excessive. This is done intentionally, so as to provide that strength and stiffness.
Generally speaking, the only place 1/4” thick plywood is used is in drawer bottoms, where there is a rabbeted groove cut into the drawer sides, to hold the bottom and provide support. If the drawers are being used to hold heavy items, then 3/8” thick plywood should be used for the drawer bottoms. Sides are often made of 1/2” thick plywood, with ¾” thick plywood or hardwood boards used for drawer fronts.
Cabinet face framing and sides are almost always ¾” thick plywood, although it is possible to make the sides of cabinets out of 1/2” thick plywood, when using a raised or sunken panel design. In that case, 3/4” plywood is used for the outer frame of the sides, with the thinner plywood being used for the panel.
Shelves should always be made of 3/4” thick plywood, although they aren’t always on commercially manufactured furniture and cabinets. Thinner plywood, MDF or particle board, which are often used for shelving, is not strong enough to support the weight that is often stacked on these shelves, especially for a prolonged period of time. The shelves end up bowing with time, causing storage problems and making the cabinet unattractive.
Adding a lip to the front or both the front and back of the shelf can go a long way towards making shelving stronger and longer lasting. The lip, which is normally made of hardwood, works like an I-beam, fighting against any deflection (bending) of the shelf, by increasing the effective thickness of the shelf.
When choosing cabinet grade plywood for a particular project, it is important to take into consideration the quality of the two faces. While in some applications, such as a carcase (the casing of a dresser) the back side of the plywood won’t be visible. In others, such as kitchen cabinet doors, the back side will be seen whenever the door is opened. Therefore, although kitchen cabinets aren’t considered in the same class as fine furniture, the grade of plywood used may have to be higher.
When selecting plywood for a project, you want all of your plywood coming from the same mill. If you were to build a set of kitchen cabinets, where half of the plywood was freshly bought and the other half had been sitting in your workshop, but had come from a different mill, it is quite possible that the plywood will be of different thicknesses, even though the nominal thickness is the same.
This difference is not intentional, but is a result of the way the plywood is manufactured. In any plywood manufacturing process, the plywood is put under pressure while the adhesive or rosin that holds the veneers together is setting. Depending on the actual wood types used in the veneers, the moisture content in them and the type of rosin or adhesive used, the amount of compression can vary. This results in the finished pieces varying slightly in thickness, from batch to batch and from mill to mill.
How to Buy the Good Stuff
When looking to buy cabinet grade plywood, there are three things you should look for:
- The face veneer – How thick is it, what does the grain look like and is the grain book matched. Any cabinet grade plywood that is to be stained and/or varnished should look like boards laminated together, not plywood.
- The overall flatness – All plywood is going to have a little curvature in the sheet, but you don’t want it to be extensive. An excessive bend or warp indicates problems with the core. These will not come out as you assemble your project, but will apply constant pressure, which could lower the life of the finished product.
- The edge – When looking at veneer core plywood, the more layers of veneer there are, the better quality it is. Hardwood cores are always better than softwood ones, even if low-grade hardwoods are used. Check how straight the lines of the rosin or adhesive are, as that will indicate how much of a likelihood there is of a problem in the core affecting the look of the face veneer.
While you can buy cabinet grade plywood from your local home-improvement center, the selection will be limited. Their inventory consists mostly of structural softwood plywood, with only a few types of cabinet grade plywood thrown in. Unless you are willing to allow them to dictate the materials you use, you are probably better off going elsewhere.
The best selection, as well as the best quality cabinet grade plywood is going to come from businesses which specialize in selling architectural trim. Even then, they will not have every grade and type of cabinet grade plywood available. You may need to visit several of these businesses in your area, in order to find the best cabinet grade plywood for your product.
If you are fortunate enough to have a lumberyard in your area, which specializes in carrying hardwoods for woodworkers, chances are that they will carry a good selection of hardwood plywood as well, allowing you a greater selection for your projects.
In addition to the face grades that are used, cabinet grade plywood is also graded by the type of core used in its manufacture. Depending upon the manufacturer, a number of different core types are available; each with its own characteristics and qualities:
- Veneer core (V/C) – This is the standard plywood core, with an odd number of layers of veneer, laid at 90 degree angles to each other. The actual number of layers can range anywhere from 3 to 11, depending upon the thickness of the plywood sheet and the quality of the plywood. Generally speaking, the more layers, the higher quality the plywood is considered to be. One risk with veneer core plywood is that imperfections can easily “telegraph” to the face layer, showing as indentations or stains in the finish. This is especially true with thin face veneers.
- Fibercore (MDF) – The entire core is a single medium density fiberboard (MDF). This tends to produce the most stable panel. The panel is extremely machineable with no voids. The fibercore’s smooth surface provides a superior core for the finish of the face and back veneer. The only drawback to MDF is its high weight.
- Pro–Core – A new “pro-core” is available from some manufacturers. This combines layers of hardwood veneer, with layers of MDF. In doing so, it adds structural strength that the MDF is lacking, while keeping the smooth, flat surface of the MDF for the veneer to be glued to. The veneer cores will be towards the inside, with the MDF layer just below the face veneer.
- Particleboard Core (PBC) – This is similar to MDF, with the exception of having a particleboard core, instead of MDF. Like the MDF, PBC provides an extremely smooth surface for the veneer’s finishing. However, it is nowhere near as strong as MDF.
- Lumbercore (LBC) – This is a five ply construction, with two thin veneers (the face veneer and one backup layer) on either side of the lumber core. The core is made of a series of edge-glued strips of lumber, ranging from 1-1/2” to 2” in width. This type of core is only found in hardwood plywood that is 3/4” thick or thicker. It provides a plywood that is extremely resistant to buckling, twisting and warping.
While veneer core is the most commonly found core used in cabinet grade plywood, the more stable a core is, the higher a grade it is considered to be. Therefore, fibercore and particleboard core are actually considered to be the highest quality cabinet plywood. This quality, of course, reflects in the price of the plywood, but it provides for a better finished product.
However, veneer core plywood is stronger than MDF or PCB core. So the same project may actually use both; with MDF core plywood on the facing side of the cabinet, and veneer core plywood being used for the back and sides, where any imperfections telegraphing through the face veneer won’t be obvious.
Architectural Woodwork Institute Quality Standards prohibit the use of veneer core plywood for some items, like cabinet doors, where any printing of imperfections in the core will become highly visible on the exterior of the finished product.
It is rare anymore to find the core veneers made of the same type of wood as the face veneers. The cost of the raw material is such that manufacturers try to use lower cost veneers for the core of their plywood. One of the few cabinet grade plywood types, which may still have a matched wood core is Baltic birch. There are no voids in this plywood, even in the core layers.
By using the same type of wood for the core veneers, as is used for the face veneer, these manufacturers produce a cabinet grade plywood which is structurally strong and extremely stable. The face veneer tends to be thicker, allowing you to sand it, without worrying about sanding right through.
This is a European product, rather than American. So the sheet size is approximately five foot square, a bit different than what we’re used to. The 1.5mm thickness on the veneer layers makes for a plywood that is very strong and excellent for joinery work. It is also considerably flatter, on the average, than other cabinet grade plywood. This is often used to build furniture with the edge of the sheets exposed, providing a much more attractive appearance than the edge of most other plywood.
Prefinished Cabinet Grade Plywood
Some manufacturers are now providing prefinished cabinet grade plywood, where the staining and varnishing is already done for you at the mill. This is primarily done for major cabinet manufacturers, where they don’t want to bother with finishing operations. But it can provide the same benefits to the small-time cabinet shop, the contractor or the hobbyist who doesn’t want to deal with finishing.
Finish operations tend to be time-consuming, especially if you want fine finishes. In construction, it has become more and more common for the painting subcontractor to receive the architectural trim, doors and windows at his shop for finishing, before they are installed in the home. This saves labor time and cost for the painting contractor, as well as making it possible to provide a very consistent finish throughout the home. It is much easier to provide a consistent finish in the workshop, than with the trim scattered all through the home.
If anything, the high volume of finishing work done in producing prefinished plywood will generate an even more consistent product, because of the methodology used. Factory-type operations lend themselves to great consistency, which reflects in the finished project’s appearance.
These same concerns apply to cabinet grade plywood used in any project. By purchasing prefinished panels, you save yourself time and money, while giving yourself a more consistent finish on the project.
Cutting Cabinet Grade Plywood without Splintering
If you’ve ever worked with plywood at all, then you’ve probably had more than one cut sheet that splintered badly when you were cutting it. This is likely to happen anytime you are cutting across the grain. Since we can’t avoid cutting across the grain, it’s good to have a method we can use, which will protect the expensive veneer surface and provide us with a clean cut.
To start with, you need to have a blade that is designed for use with plywood. The blade that came with your saw, regardless of what kind of saw you bought, is not designed specifically for plywood; it’s a general use rip blade. That’s not what you want. Investing in a quality plywood blade is worth it. The more teeth the blade has, the smoother a cut it will provide; but a high tooth count also means cutting slower, as each tooth is taking out a smaller chip.
Always use a sharp blade. Once you get used to using a quality plywood blade, you will begin to recognize when your blade is getting dull, as it will be even more likely to splinter. It’s time then to change the blade, sending your old blade off for resharpening.
Be sure that as you make the cut, the face side of your plywood is towards the outer perimeter of the blade. This means that you want the face side up when using a table saw, and down when using a circular saw, radial arm saw or miter saw.
Finally, add a strip of masking tape right over the cut line, on both sides, before making the cut. This will help hold the grain of the wood together, rather than splitting. Make the cut smoothly, maintaining the same speed. Be sure to remove the tape when your cut is finished, especially in the heat, so that the adhesive doesn’t stain or stick to the wood.