GLUES

Glues are comprised of compounds from nature such as “hide” glues and “paste type” glues which, when hardened or cured, can be broken down with water and steam for reuse. This is why hide glue is used for some fine furniture repair or the repair of musical instruments. When taking a musical instrument apart for repair or replacing parts, hide glue can be steamed loose. The area that was once glued can be cleaned and re-glued with the replacement part without damaging the instrument. Adhesives, on the other hand, are based on artificial, man-made compounds such as epoxies and PVA glues (i.e. the yellow and white “carpenter” style glues).

The type of glue I found to be the best for inlay, is a type of super glue, sold on the shelves in hobby stores as “Cyanoacrylate”. This is great stuff for quickly gluing small pieces of inlay. It sets in about 10 to 20 seconds depending on: moisture content of your wood; the PH or acidity level of your wood; and of course your workshop temperature and humidity. Generally, after 15 seconds, your piece of inlay is permanent. As you can see from the photos, you can create colourful, finished inlay work by using the natural colour of the many exotic woods available.

WOOD SELECTION

There are many beautiful, exotic woods with outstanding colour available at many wood and lumber supply stores.

I use African padauk or Burmese padauk (a nice orange colour), purple heart (purple in colour), African blackwood (both black-early wood and yellow-late wood – gives a beautiful contrast for inlay), Brazilwood or pernumbuco (carmel to deep brown), cocobolo (very rich brown to almost black), Magassar ebony (black to rich brown). Burled rosewood also makes for attractive finished inlays. Our domestic species, such as walnut, osage orange, cherry and apple will also add a great deal of colour to your inlay projects.

TOOLS AND ACCESSORIES

Super glues are available in various thickness or densities – thin, medium and thick. I use the thin-density glue for hardwoods with a close grain (such as hard maple, beech and birch) and the medium or heavy-weight glue for woods having a wider more porous grain (such as oak, ash and some cuts of walnut).

Plug cutters are required. Important: use the straight cutter as opposed to the tapered cutter. Tapered cutters will not give you a tight inlay and, depending on the manufacture, the taper will not match the exactness of the forstner style bit, creating an inlay with gaps.

When choosing your cutters you have the choice of metric or imperial measured diameters I choose the imperial measured diameters. Plug cutters come in diameter cuts of 1”, 7/8”, 3/4”, 5/8,” 1/2”, 7/16” 3/8”, and 1/4”. With these sizes you can create almost any type of inlay.

DESIGNS

Although the inlay designs are quite easy and uncomplicated, the number of design creations are endless. Especially when using exotic woods with their natural colour.

Shown are sample drawings or patterns which I use for some of my designs. They are drawn with the use of various templates. When your inlay becomes a little more complex its best to number each plug so you know which plug to inlay first. This will help you to overlap each insert in order.

FIRST STEPS

Match your forstner bit size with your plug cutters; get thin and medium viscosity glue; have a smaller clamp handy; and precut a number of different size plugs – if for no other reason than to have a ready supply available for your inlays.

CUTTING

When cutting your wood plugs, cut 1/16” and 1/8” thick strips from 1 1/2” to 2” thick stock. This allows for easy plug cutting through a thinner material. A plug 1/16” or 1/8” thick is sufficient in thickness for most of your inlaying. Sometimes you may find it necessary to cut 1/4” or even 3/8” thick plugs. If you decide to get into curvature inlay work you will want enough material to file and sand to produce curved, convex or concave work.

When plug cutting hardwoods, reduce the speed of your drill press to avoid burning the edge from your cutter. When cutting softwoods you can maintain your drill press’s normal rpms.

The “swirl” design, showin in the lead photo, is very easy to do and very attractive.

INLAY

Once you have decided which inlay pattern to go with, you have all your plugs ready and you have your pattern drawn on a piece of wood, then you can begin to drill your first inlaid piece (or plug) with your forstner bit. Be careful not to drill deeper than the thickness of your plug. REMEMBER it’s better to sand off than to fill in.

I used a piece of birdseye maple to inlay. It has a close grain and is quite dense so I used the thin viscosity super glue. Drill the first cavity and quickly brush the piece of padauk with sandpaper to remove natural surface oils. This ensures better adhesion. With this type of “swirl” design it isn’t necessary to draw anymore circles. Just let the forstner bit do your circle drawing and follow the circumference of the large circle.

Evenly distribute just a few drops of glue in each cavity, to secure your inlay. Press-fit your plug and then, quickly, clamp for 10 or 15 seconds.

Use walnut, or wood with a contrasting colour, for your second plug. Make a second cut partially overlapping your first inlay. Repeat this around the circle using alternating wood colours. You may wish to add an ebony inlay with every fourth inlay. Remember to clamp each inlay, or press firmly with your finger for the required time.

Once all your plugs are inlaid you may wish to go a step further and inlay the last 1” diameter plug with smaller inlays. Sand and finish for exquisite results.

TIP

Some of the hardwoods will adhere faster if you roughen the plug to be inlaid on a piece of sandpaper. Because cyanoacrylate glues are somewhat sensitive to acids and moisture in woods, brush each plug with sandpaper. This removes some of the natural resin in the exotic woods and increases adhesion.

TIP

There are a couple of things to be mindful of when applying a finish to your creation. Using a lacquer coating with a nitro cellulose (a type of an industrial solvent base) can force the natural colour out of some of your exotic woods such as padauk and purple heart. Therefore, it is generally best to apply a very light coat of lacquer over your inlay. Allow it to dry, then apply the desired number of coats. You may wish to use a urethane finish, which has an oil base and is less harmful to the wood. Hand rub each coat with a least 0000 steel wool to produce a much nicer finish.