The various types of plywood have found a home in a wide range of uses. From construction to furniture, with hobbies and trinkets in-between, we can find various sorts of plywood all around us, each and every day.
Of course, not all plywood is created equal and it can’t all be used for the same purpose. Trying to make furniture out of construction-grade plywood results in poorly finished furniture. Using particle boards for subflooring in a moist-rich environment will ultimately lead to failure of the floor, with the potential of people being injured in the process.
When it comes to furniture, higher grades of plywood are usually used, although there is plenty of furniture out there made of particleboard. In either case, treating the edges of the panels is important, so as to hide the end grain. By and large, the end grain of boards is hidden in most furniture, unless it is being used for a specific accent purpose, such as for end grain wood cutting boards and countertops.
The problem with plywood is that all edges contain end grain, unlike boards of solid lumber, where only the ends contain end grain. So there are cases where it is impossible to hide the end grain by using a piece of trim or structural member. Some sort of trim must be applied.
Wood Edge Banding
Wood edge banding is nothing more than strips of wood veneer. As such, it is available in a wide variety of wood types and grains. Since it is actual wood, it will usually match a project quite well, looking as if it is the edge of the board.
There are two types of wood edge banding available, either with heat-activated glue or without glue. The type with the glue on it is easier to install, as the glue is essentially the same as that used with a hot melt glue gun. It can be installed to the edge of the panel with a clothes iron to provide the heat and press the banding onto the edge of the board.
Be cautious when applying wood banding in this manner, as too much heat can scorch the wood. Ideally, the temperature of the iron should be just enough to melt the glue, no more. With the glue just barely melted, it will solidify rapidly, preventing the banding from lifting.
Once applied, the wood edging should be pressed down, by rubbing it with a bunched-up rag, to ensure that the banding is smooth and snug up against the edge of the wood panel. If high points are encountered, they can be repaired by going back over them with the iron.
Working with the type of wood edge banding that does not come with the glue applied is a bit more difficult, but not extremely hard. This type of edge banding is applied with normal wood glue. In order to do so, glue is applied to the edge of the panel with a roller bottle. Then the wood edge banding is set in place, “clamp” it in place with masking tape to dry.
In cases where edge banding is not available that matches the type of plywood being used, it is possible to create edge banding by cutting off the face veneer of some scrap plywood pieces which are longer than the finish size of the edge banding needed.
To do this, set the table saw fence up so that it is close enough to the blade, so that only the thickness of the face veneer is visible on the other side of the blade. Then rip the piece of plywood, making a slot that is ¾” to 7/8” high. The now loose strip of face veneer can be cut the rest of the way through with a hobby or utility knife. This strip can then be applied to the panel in the method listed above for wood edge banding that doesn’t already have glue applied.
Wood Strips for Edging
Some people don’t like using wood edge banding because it can be chipped easily. To create a stronger edge, which is more resilient to rough handling, it is better to cut wood stripes of the appropriate type of hardwood and glue them to the edge of the boards. This is especially good for shelves, where things will be put off and on the shelf constantly.
There are several different ways of doing this, as shown in the diagram below. The key, in all these cases, is accurate cutting, so that the two pieces fit together snugly, without leaving any gaps.
One nice design option that this allows is to use a contrasting wood for the edge than what is used for the main part of the panel. For example, birch plywood might be used for making shelves, with an oak edge strip applied for accent.
When installing any edging like this, it is necessary to clamp the edging to the board, while the glue dries. Due to the edging being very thin, a backing board should be used, spreading the clamping force of the bar clamps over a larger area.
Leaving the Edge Exposed
Mid-century modern and “industrial” style furniture is popular these days. While mid-century modern would never leave exposed plywood end grain showing, it is very common with industrial style furniture. One common place this is seen is with plytabletops, often made out of plywood sheets that are 1” to 1 ¼” thick.
These are made out of cabinet-grade plywood, providing a quality surface finish, as well as thin veneers in the core. The large number of thin veneers provides an attractive edge, especially when milled. However, the core veneers used in this type of plywood are not void-free, like marine grade plywood is. There may be some voids that need to be dealt with.
Since the finish applied to the edge grain is usually nothing more than polyurethane varnish, filling those voids must be done with care, so as to ensure that the fill is not visible once the tabletop is finished. This is best done with tinted putty, rather than “stainable” wood putty.
Tinted wood putty is available in a wide range of colors, intended to match common wood tones. It can also be tinted with standard tints, allowing special colors to be created, if needed. But in this case, standard colors will usually work, as the core veneer layers of cabinet grade plywood are usually softwood or beech, colors that are easy to match.
To determine the color that will be needed, it is helpful to wet the edge of the plywood with mineral spirits. This will cause the wood to darken, just as it will when varnish is applied. With the wood darkened, it is easy to select a tinted wood filler that matches the color of the veneer layer that needs to be filled. If the exact color cannot be found, these types of putty can be mixed to come up with other shades.
One thing that can be useful when working with this type of putty is mixing in either chalk dust, also referred to as “painter’s whiting” or sawdust. If sawdust is being used, only the finest of dust should be added, after passing it through a sieve to separate out the larger pieces.
Always overfill when working with any sort of putty, as the putty will shrink slightly while drying. The wetter it is, the more it will shrink. So if sawdust is added to the putty, thickening it, it will not shrink as much. Once the putty has dried, it will need to be sanded with 150 to 220 grit sandpaper, making it flush with the edge of the panel, before varnish is applied.
Edges with Painted Panels
Painted plywood panels do not require any special treatment in the form of installing an edge banding. However, much of the commercially produced furniture uses a vinyl strip, which is installed into a slot routed into the edge of the panel. This type of edging is available, although it usually has to be procured through a commercial outlet, rather than a lumberyard or woodworking supply.
This sort of edging is installed by hammering it into a slot cut into the edge of the panel. For commercial installations, this is done with a pneumatic repeating hammer, but it can also be installed with a normal hammer or rubber mallet.
Another other common option with painted plywood furniture is to simply paint the edges. The problem with this is that the edges aren’t always smooth enough for painting, as there are voids and the end grain may not be very smooth. A simple solution to this problem is to putty the edge and then sand it smooth before painting. However, that is time consuming, both in waiting for the putty to dry and in sanding it smooth.
To make that easier, use ultra-light spackling rather than wood putty. The fine grain of the spackling goes into the end grain easily and dries quickly. It can then be sanded smooth with 150 to 220 grit sandpaper, readying it for painting.