How To Inlay A Fingerboard With A Pearl Design

I decided to show you how I am going step by step on the blue shark that will go on the chimera headstock classical guitar for Dr. Douglas Fields.

First things first; this is on a NON-radiused classical fretboard. That makes this one easier. It's totally flat. The board is ebony, also easy. So, this is an EASY inlay!

Here is the inlay so far. This photo includes the original art, (lower right), the photocopies for cutting the pieces, the odder materials, (blue/teal plastics in this case, and black Tahitian pearl) other more regular materials include ebony, and regular mother of pearl. The inlay is already cut out and glued up together. I use 003 jewelers blades, and a normal jewelers saw as well. Nothing special there. Recently I have started to use size 1 blades, as they seem to be much more tight against the cut, and give you a more even edge cut from top to bottom.

The main thing with inlay design is originality

For example....
Start out like this: "I really want a killer inlaid tropical rainforest scene on a guitar, how can I make that happen?". THEN worry about materials, etc. If you're staring at a single piece of pearl in front of you and wondering what to do with it you are limiting yourself a lot!

You'll notice design-wise that the shark is extremely foreshortened, it looks like it's swimming out of the fretboard. Also the top fins are cut off; he's swimming through the board. You don't need to shove or fit the whole design into a small space. The human mind will piece in what is missing as long as the main parts of the image are there. Too much and it looks off, but done correctly it adds a new dimension to the art, and looks completely unique. 
 

Some more on drawing up your inlays

1. Make sure all your lines join each other so they can be cut out separately later like a puzzle. Any un-joined lines mean starting over. You can create free ending lines with a graver tool as your engraving skills get better. More on engraving later
2. I draw all my art for patterning with a drafting pencil. I use #8H lead; very hard, for drawing thin clear lines. These lines will photocopy nicely, and are good for getting extremely close tight cuts. The thicker the pattern lines, the more off your cutting can end up and the more gaps between pieces you will have in your inlay. These are hard to hide, so just prevent them with a good pattern and good cutting to begin with.
3. When photocopying you can shrink the pattern a little, making the lines thinner.
4. Make about 15 or so photocopies of your original, and use these to piece out your inlay materials.

More on materials and thickness

I do not use any backing. I glue the pieces together with thin cyanoacrylate glue. I am most interested in the surface color of my materials. I will glue everything FACE down so that the surface of the inlay is completely even. It doesn't matter if the back is a little uneven. When fitting, I rout to the deepest piece, and use dust or something to life the other part of the inlay up. The glue will fill in the back. This preserves your surface colors. Just make sure the inlay sits flush to the surface in the rout pocket. Any shell sticking up will get sanded down, and your color patterns may change or even go away. This becomes a little more tricky on radiused fingerboards, but it can be done. More on that later.

Filing is for the areas where you didn't cut as accurately as you SHOULD have. Don't PLAN on doing it, and if you're going to make mistakes then cut outside the line, so you don't have to throw out the piece. The goal is to cut away the lines, leaving a completely tight fit, each piece having it's half of the original line shaved off, totally tight. You will gain those skills as you go. For a complete beginner some filing is going to happen. It happens to me in almost every piece (total piece that is, not each piece of shell). Most are tight from the start. Pierced pieces almost always need at least a little something filed off.

Next is positioning

Find the place where the inlay is going to go and glue it down temporarily with some contact cement. NOT CA or epoxy as those are too strong! You want to use something that you can release with acetone. Put a drop on the bottom, position your inlay and let it dry in place for a few hours at least.

If you don't let it dry you will mess up your scribing, and have to start over again, and that can be a real pain. Don't rush it, do it right, be patient, and fight the urge to touch anything. That's the hard part! Just let it sit until it dries.

Once the inlay is dry I use an exacto #11 blade and go around the inlay perimeter, scribing out the pattern.

I then carefully lift off the piece and go over the scribed lines again with the blade, deepening the cuts. This isn't really necessary, but I like to make sure I have a clear pattern to rout to. I then clean off any residual glue on the inlay and the board with acetone. This keeps everything clean, otherwise your depth and height of your inlay pieces could be thrown off by the glue residue.

I rout using a Foredom flex shaft tool. Basically a fancy Dremel. I use The Stew-Mac downcut carbide bits in decreasing size as I get nearer to the edge of the rout pattern. I normally end at the 1/32" size. These bits are great, last a long time, and cut extremely clean.

No pictures of routing, sorry. You guys know how to rout though, right?

So, we have scribed around the inlay, removed it, cleaned everything off with acetone, and rubbed white chalk over the lines to highlight them as a routing pattern. We then got our depth and routed to as perfect a fit as possible.

Check your depth with a scrap piece of the shell that is the thinnest in your inlay, to make sure the depth is where you want it to be. Remember it's easier to rout deeper, raising an inlay takes a little practice as the glues in most cases shrink, so you have far less control over that. After the rout is done, and everything fits nice, fill the hole with your glue. If its epoxy make sure you mixed correctly, and add some to the hole, then add the inlay, then add more over the top. Make sure every seam and open area is filled with glue. If using CA, use the thinnest you can find, fill some in the hole, place in the inlay. In darker woods like ebony, take some ebony dust and pack dust fill the edges between the rout and the inlay with the dust. It will seep in making the edge look almost flawless after leveling, and it keeps the extremely thin glue under control from running all over as you add glue.

The thin glues are about the same viscosity as water, so be careful with them. It's easy to get it all over, AND it's superglue. Wear a mask and eye protection as well for any of the woodworking steps.

Superglue can cause a reaction almost like getting the flu. Trust me it is extremely lame. I work the glue with a mask AND a fan going. The ebony dust trick works nice in ebony and dark woods, however it does not for almost any other woods.

Train yourself to be patient and rout tight and clean. That is the real key to good inlay- good design, interesting use of materials, tight cuts, and clean routs. At this point your inlay should look like crap.

Clamp the inlay down. Epoxy doesn't shrink, and the inlay needs to sit as flush with the rout as possible.

You'll notice the two different glues in this picture. I use the green Duco cement to hold inlay to the wood for scribing, and the red 3M glue for piecing out the pattern on my materials.

Many people use CA for patterning, but CA won't hold paper well to gold or black pearl, and it lifts off easily while cutting patterns. That is a sure fire way to screw up your pattern during cutting, and you will have to re-cut the piece. The 3M glue is one part, and dries fast. It's a little gelatinous, so make sure your pattern sits FLAT on the material. Raised pattern means a mis-shaped piece. It sticks to every pearl and stone and metal I know. I really like it.

After 24 hours you can start to level the inlay down. I don't care how long the package says it takes the glue to cure, or how much of a hurry you're in because your so excited about the piece. You want your work to be around for years, so why not take the proper time making it? Let the glue fully cure. Otherwise you may be sanding wet glue.

Using a flat bottom solid wood block (any other will possibly have flex to it, sanding unevenly- a no-no on musical instruments- especially fretboards) start at 80 grit, and work your way down to 120, then 220, then 400 grit papers.

I start using 120 about when there is still glue all around the inlay, but the inlay itself is becoming visible. I go to 220 grit when the glue is almost gone, but there is still enough to see the glue clearly. When the glue is almost wisp thin, but still there, I go to 400. I use them all dry except for when leveling plastics. If I have plastics in an inlay, like the shark here, I'll go to 220 dry, then finish off with 400 wet, (or with oil) and then even go to 600 to buff out the plastics. Some may need higher grits.

About this stage in the photo I would still be at 120, but not for long. Just until I see the glue going away enough to make the inlay seem flat. You can switch to higher grits sooner to be safe, it just means a little more sanding time. If you go too far down on a fretboard kiss the board good-bye, especially if you can't re-radius it out. THAT is why I never support sanding an inlay going fret by fret.

After it's level you may need to go back and pick out any bubbles, etc.. the glue formed while it was drying. I like to use the #1 blade, and dig them out until the white dust is gone, and fill them with the CA. It fills clear and fully. If it's in ebony, and you can't get out the bubble or the white dust out all the way, I have a little trick- clean out the bubble as much as possible- take some black India ink and fill the bubble with that, then seal that with the CA. Of course it only works in ebony, but its fast, cleaner than filling with ebony dust. Re-sand the new glue down again starting at 220.

If you're happy with the inlay you can stop at this point, and you should be pretty proud. I am almost never happy with it at this stage, so I break out my graver tool to add all those details you can't get with cuts.

The graver is the silver one with my technical pencil on top. Most people use a handle on it as well, but recently I have been having a better time without the handle. I feel like I have more control without it. Gravers are used for engraving, and I am FAR FAR from an expert on that. I am learning as I go on engraving, but I can tell you far less people hand engrave these days than do inlay. I wish I knew of a good tutorial on it, but I don't. Gun engravers can teach you how to engrave, but they are few and far between as well.

What little I know basically is this. Draw out your pattern on the material you want to engrave on with the pencil, or pen if you're good enough to control the ink. When using pearl try to choose the most pattern free/plain MOP you can find. High figure pearl with blur the lines with the pattern, and it fractures out easier.

After you draw out your pattern, gently (one wrong scratch means you just ruined all your previous work- not fun on a 75 hour inlay... - No I'm NOT kidding- you can't fill an incorrect deep graver scratch. You can only SAND it out) and gently scratch away at your pattern going deep with the graver each time. You will make a little "track" for your graver to follow as you go, but the key I have found so far is relatively low pressure, and smooth tracking. Stop after each pass, and replace the cut. Fill your cuts with either colored wax paste or inks.

Remember, the engraving will wear with play, so keep your highest engraved areas toward the more non-used regions of the fingerboard if that's where the inlay is going. Proper engraving takes hours. It's a separate art to inlay, with rules and skills all it's own. Take your time and don't rush it. Some engraving artists' engraved pieces took years.

Here is one last complete parting shot with engraving you can see the details make the piece.