Finishing Details

An old saw about the construction business states that the last five percent of the job takes as long as the first ninety-five While this obviously can’t be true it sure seems true. My guitar build is rounding the stretch but I don’t yet feel like I'm thundering down to the wire. Like fitting the rails and balusters to the staircase on a long remodel project, fretting the guitar’s neck, carving and gluing on the bridge and putting the actual finish on the box and neck are all steps that will “show”, either competent craftsmanship or that other thing that I always hated, sloppy work.

I had the fretboard glued to the neck already when my friend and actual luthier, Wade, told me he always installs the frets in the fretboard first. It didn’t take me long to find out why.

The frets are the half round wires in the fretboard that determine the string length and thus the notes played; you press the string behind a fret, which shortens the effective length of the string, raising the pitch of the note you strum or pluck. The half of the fret you can’t see is a barbed tang that seats in the slots precisely sawed in the fret board, hopefully seats I should say. I started out hammering the frets in and then realized that the fret board wasn’t yet tapered to fit the neck, a step that would become much more difficult with metal fret ends in the way.

These first four frets did indeed hang tough on their barbs, pulling them out did some damage. Still, I persisted. With planes, rasps, and files I worked the fret board down to the sides of the neck and then tried one more time to hammer in the frets. This time they wouldn’t seat…hammer one end in tight and the other end would pop up. A game of Wack-a Mole with no winner, and I gave up before long. Maybe they would seat if I pried the fretboard off the neck and tried it Wade’s way.

Using an old drywall finishing “knife” that was worn to a thin edge I popped up one end of the fret board and was working my way to the other end when the damn thing broke, which settled the immediate issue. Obviously I was going to start the whole process over.

I had a couple other pre-slotted fret boards, but monkeying around with the frets I had installed had bent several of them beyond repair. I sent an order for more fret material across the webs and turned to see what I could do to the guitar body.

Most production guitars today are finished with nitrocellulose lacquer, a durable, and when correctly polished, beautiful product. It’s also toxic to work with, requiring the use of a sophisticated positive pressure vapor mask, a dust free spray booth, and of course the compressors and guns to shoot it. Yuck. Thankfully there is another way, using non-toxic and natural products, a way that dates back centuries.

The product is shellac and the process is known as French polishing. I had been scouting this territory on YouTube for months and had already bought the supplies for the trek. Shellac is made from a resinous deposit left on trees in Asia and India by beetles as a protective coating for their eggs. People scrape off the resin, known as stick lac, sieve, wash and dry it in the open air, and bag it up for wood workers or commercial shellac manufacturers.

When ground and mixed with alcohol the resin dissolves into a clear varnish which can be brushed or rubbed on with a cloth pad onto wood. The alcohol flashes off leaving the resin coating behind, evaporating so quickly that several thin coats can be applied a couple of minutes apart before you need to stop and let them cure.

As a natural product, shellac has a relatively short shelf life, and commercial producers use denatured alcohol as the propellant. Instrument makers make their own in small batches, and grain alcohol works just as well as the more harsh denatured versions. I had a baggie of blonde lac flakes, I had an old coffee grinder, I had a jug of Everclear (95% potable alcohol), I was in business.

My buddy Jack pointed out that since alcohol is an intoxicant, my shellac technically wasn’t non-toxic, there’s always a smart guy around when you don’t need one. Using a diet scale to measure, I mixed an ounce of flakes with four ounces of booze in a used peanut butter jar, sealed it up, and sloshed it around whenever I remembered. In three days it had turned to a clear golden liquid, somewhere between a lager and a pale ale, now to make a “rubber”.

That’s what the French polishers call this sophisticated tool, basically a ball of cotton or wool wrapped in a single cover of clean, lint free cotton. You can use the same rubber to “body up” shellac layers as you use to French polish it out to a clear luster, no fancy, natural fiber varnish brushes needed. When you judge that you have applied enough body coats you wet sand the surface smooth, using fine wet/dry sandpaper and either water or olive oil for the lubricant, and then you are ready to rub.

This time you apply equal-ish amounts of the shellac and alcohol to the rubber, I used an eye dropper, lightly dab some olive oil to the rubber surface for lubrication, smack it on the back of your hand to mix the ingredients and then polish away, kind of like polishing your shoes (does anyone do this anymore?) without the polishing brush of course.

Results can vary, dependent on the feel you develop; let the rubber get too dry and it starts to stick to the surface leaving marks that have to be rubbed out, put too much shellac or alcohol on the rubber and it smears the polish you have already established. This is very much a Goldilocks technology, but if you haven’t got it “just right” you can always do a light wet sand of your mistakes and start again.

Turns out what looked like nice “figure” on the back and sides was actually sparkling, golden flecked figure, even though my French polished surface was nowhere near as perfect as some nitro cellulose jobs I have seen on the internet. I was totally stoked, and left it about 90% done to turn my attention to the top.

The first step for shellacking the top was to mask out the locations of the finger board extension and the bridge, both of which end up glued to the top. I bolted the neck on for about the fiftieth time and lightly penciled its outline, and then most carefully measured from the nut slot at the tuning end to mark where the bridge would land…measured wrong of course, locating and masking from where the saddle should be. The saddle is inlaid into the bridge and is where the strings actually make contact. Since it is set a quarter of an inch or two back from the front edge of the bridge, my masking was a quarter of an inch too far from the nut slot.

Well into polishing the top I checked this length, noted the discrepancy, grumbled a little, and peeled off the masking tape to reveal the unfinished footprint for the wrongly placed bridge. Not a major grumble however; some sanding and re-masking, body up the bare spot with more shellac, tomorrow I’ll sand it out and go back to polishing. This is something you don’t just do with a modern finish, though patches are possible. Thanking the old ways again, I’m in no particular hurry and that finish line is creeping closer;)




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John Griswold

John Griswold

Master carpenter, watercolor artist and beat up old jock…owned by Black Lab Bo who considers two tennis balls a minimum mouthful

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