Introduction:

The finish of your instrument is what is supposed to protect the wood from the elements, add durability to the surfaces, and while at it why not add some color.

Well, the finish can only protect the surfaces it is applied to, and many instruments have vulnerable areas exposed, like the recess for a bolt on neck, which can dry and crack or soak up moisture and with that expand, and even mold.  Its ability to protect the instrument from scratches and dings is almost non existent, if applied thin enough for the instrument to resonate well.  The color thing is a mater of taste, and the timeless look of wood grain can easily stand on its own, even more so when the woods are naturally figured.

There are many types of finishes like lacquer, varnish, urethane and others where not only the names are often used interchangeably even by manufacturers, but often the chemistry too, so being very specific is not possible given the vast possibilities.

The following paragraphs should give you some information on the various finishes, and an idea of my dealing with them, and why I avoid most of them like the plague.

Important Information:

The chemistry and physics involved with a finishing media dictates the preparation of the surfaces prior to, the necessary environment for, and the method of its application.  If any of them are not adhered to closely, and conditions are not right, the final results can range anywhere from pretty bad to completely unacceptable.

Some finishes require a controlled environment in the form of a spray booth that not only handles ventilation for the person in it, but also temperature and humidity control, and isolation from dust and debris, add to that some finishes need light in varying wavelengths as a catalyst.

I do not have a spray booth yet, nor the spray equipment required to guarantee great results.  On the other hand I am well skilled in finishing except for matching colors (even computer aided matching is hit or miss).

I do include finishing as part of repairs with limitations, but do not offer, repaints, restoration, or cosmetic touch up.  I do not offer relicing either as I not only consider it cheating, but down right silly.

French polishing:

French polishing is a process of applying Shellac, an ancient resinous substance made from the secretion of a bug used for its cocoon, dissolved in denatured alcohol with repeated coats.  As a matter of fact, so many coats are hand rubbed onto the wood that the process takes weeks to complete, and it is mainly used on classical guitars of very high quality.  It is not used very often anymore as the amount of labor is cost prohibitive.  I do not use this method, as there are other ways to apply shellac, and its derivatives known as lacquer.  The most distinguishing property of shellac based finishes, is that they are shiny even without sanding or polishing.  I would be surprised to come across an instrument finished in shellac or lacquer these days.

Nitrocellulose:

Nitrocellulose is a very common finish used mainly between 1933 when it was invented until the early 1960's where plastic based finishes started appearing.  For the most part it is made through nitration of cotton, and to this day is heralded as the best media for acoustic guitars by discerning players, because it can be applied very thin, and dries to a rather hard finish that does not mess with the sound to much, and can be redissolved for repairs.  It will darken over time, and is highly flammable both before application, and once dry.

Due to the fact that nitrocellulose can be redissolved, it is also prone to doing just that, when a guitar spends a large portion of time in a case with little room for fumes of the solvents used in it and in similar glues to escape.  Even the binding and pick guards are often made out of or with a form of nitrocellulose, that can turn to gel, and give off fumes causing trouble.

I do use it whenever an instrument comes across my bench that is finished with it, although it is nearly impossible to match colors including the discoloration from aging, and if it does look right when done, it most likely wont a few years down the road.