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       Jul 27-Aug. 1, 2014

I had the great the pleasure of being back East the first weekend in November and the timing was perfect to catch Mother Nature's colors at their best. It seemed like the window of greatest opportunity was about two days, and during that time - especially when the sun came out - the leaves were every color imaginable. As I think most of you know, I don't take trees and wood for granted and I'll never cease wondering at how much service, functionality, and joy this wonderful resource brings us.
And, Autumn marks the time when the cold weather forces us to spend more time indoors - and hopefully, more time on luthierie projects. This is a time of special care in the shop. Don't forget that heaters and stovepipes present a special hazard around wood and finishing materials. Please try to work diligently to keep your humidity and shop temperature at a constant level during the winter, to the best you can.

We just had another great Luthierie Camp, and one of the Campers suggested that we prepare a step-by-step document of the things to do when you leave Camp and do the finishing steps in your shop. While the list begins where we leave off in Camp - after the instrument is fully assembled and tap tuned - I thought the document might be helpful to the rest of you. If nothing else, if provides a step-by-step outline of sequence we like to follow once the instrument has been put together. I'm happy to share it with you if you drop me an email and put "Step-by-step" in the subject line.

In our last newsletter I presented my views on various types of truss rods, and the thrust of the discussion was that I much prefer one-way adjustable truss rods instead of non-adjustable or two-way adjustable rods. In that article, there was a typo and part of a sentence missing and it caused some confusion. The sentence read "And, lastly, carbon fiber is very light; much lighter than a steel rod, and much lighter that the wood around it." That statement is incorrect; carbon fiber is very light, lighter than a steel rod of the same size, but is about two and a half times heavier than maple, and much stiffer than the wood around it. My greatest concern with carbon fiber inserts is that they are not adjustable.

As always, we appreciate your communications and your business. Here's wishing you and your family a wonderful and delightful Thanksgiving!

It's not unusual for a luthier to spend 100-150 hours building a mandolin - especially when there's great attention to detail. After all that hard work, the real litmus test is the finish; a great finish can make a less-than-perfect instrument look GREAT, and a poor finish can make a beautifully executed instrument look shabby. And, beyond the issue of appearance, a poorly applied finish can rob an instrument of tone, sustain, and amplitude (loudness).

Most commercial builders today are spraying their finishes and using either a quick-setting lacquer or a two-part polyurethane finish (the "two-part" being the addition of a accelerator-hardener). For these larger shops, they are looking for efficiency, the ability to process many instruments per day, and a short time between the application of the finish and the buffing wheel. Further, for sales and warranty reasons, they seek a finish that is bright and shiny, can withstand the rigors of going from gig to gig, and one that can resist the dramatic changes in climates and seasons. Typically, these shops are equipped with spray booths, particulate collection systems ("fume scrubbers" to remove lacquer dust from the air), air-supplied masks, large ventilation systems, racks on which to hang many instruments, and so on.

Most private builders are forced to seek more simplified methods. And while there are a ton of finishes on the market that one could select from, some as simple as wipe-on oil-based finishes, it boils down to being only French polish and lacquer that really lend themselves well to luthierie.

French Polish
French polish is a method, not a compound. Simply stated, French polish is the method of rubbing a finish in place by using a specific compound of varnish along with alcohol which promotes evaporation; softens, levels, and helps move the previous coats of varnish; and speeds up the drying process, and a small amount of some kind of natural oil like linseed, walnut, olive, or similar oil which lubricates the surface and allows the luthier to keep rubbing on the finish without getting stuck. For those with military service, French polish is akin to "spit-shining" boots.

French polish is only mildly hazardous to use, the finish is light, it fills the pores well, it is very easy to touch up if there are scratches or wear marks, and the light application of the finish offers great acoustical properties. (In the true tradition of French polish, the wood first gets a sealer coat of thinned hide glue or egg whites to fill the pores.) The downside is that the process requires a lot of rubbing and handwork, takes several weeks to harden sufficiently before the instrument can be played, is only moderately durable, and can only be brought to a very good shine (which is not as sparkly bright as lacquer).

Lacquer
There are a few different types of lacquer, and the ideal one to use for instrument work is nitrocellulose lacquer. Lacquer needs to be sprayed, should be thinned to about 1 part lacquer thinner to 2 parts lacquer, and the best spray methods are done with a small spray gun (which some automobile body folks refer to as a "shading gun"). The vapors are hazardous to inhale, the overspray should be captured in some way, wet sanding is required between every three to four coats, and the finish while durable is brittle and prone to chipping. On the positive side, lacquer is very durable, can be buffed to a brilliant shine, and provides a long lasting protective shell for the instrument. (Some spray-can lacquers have retarders in them to prevent the lacquer from setting up in the spray nozzle, and not all of them have quality nozzles so it is wise to test these on separate wood before finishing your instrument.)

Acoustical properties
In my book The Luthier's Handbook, I performed some tests to measure the acoustical response from pieces of wood that have received several coats of finish. Most builders have to spray about 12-14 coats of lacquer to get the desired finish. Up to about 4 coats of lacquer, the finish appears to have minimal impact on tone, sustain, or amplitude. While one would think that applying the comparatively heavy lacquer would weigh the soundboard and backboard down and lower its pitch (which it does when it is wet) the change is offset as the finish hardens, making the soundboard and backboard stiffer which results in raising the pitch again. But this offset only works positively during the first 6-8 coats. After that, the lacquer begins to impede the flexibility of the soundboard and backboard and begins to have a negative affect on the instrument's tone, amplitude, and sustain.


Herein lies the great benefit of the French polish technique. In French polishing, the finish is continuously applied and wiped off at the same time, leaving a very thin coat of varnish on the surface of the wood while allowing the pores to get filled. In the lacquer process, even after wet sanding, there are still many layers of residual lacquer on the surface that results in a comparatively thick finish. It is this attribute of French polish that makes it superior from an acoustical standpoint over varnish or any of the poly finishes.
 
The above chart shows my subjective opinion of the comparative features of French polish vs nitrocellulose lacquer. Higher ratings on the chart refer to "better," "more" "harder," "faster," while lower ratings suggest "worse," "less," "softer," "slower," and so on.

The scroll of the F5 mandolin and H5 mandola are beautiful and delicate, and crafting them perfectly is an art. Key to developing good scrolls is understanding what they represent. During our Luthierie Camp programs, we spend some time talking about Orville's scroll shapes and embellished pegheads and suggest that they are highly representative of the Florentine Art period (1400-1600AD), an era in which nature had a great influence on the development of art styles centered mostly in Florence, Italy (at that time). In this style, asymmetrical and rounded shapes were typical, and the influence of natural elements and plant forms played a key role.
 
Before our Campers begin the final shaping of their scrolls, I bring into the classroom a leaf and suggest that the Campers think of themselves as Mother Nature crafting this leaf into their body scrolls. It is my hope that this helps guide the mind and hands more effectively than just making a curly "peak" in the wood, and several Campers have commented that playing the role of Mother Nature has helped them.

Many builders today embellish on the body scrolls making the peaks somewhat amplified and exaggerated. By contrast, the body scrolls on the original F5 mandolins were rather subdued, but extremely delicate and well crafted. In the following photo, you can see the comparison of the front and back scrolls on an F5 (taken of Loar's personal F5).

Notice that the soundboard scroll (left) is not as pronounced as the scroll on the backboard (right). I don't believe this was intentional, but just a result of the instrument being hand crafted. The scrolls rise from nothingness, and their peaks raise gracefully as they wind up to the button of the scroll.

Of course, the right tools help, too. The scrolls can be shaped with sandpaper and slowly smoothed and sculpted. Another great resource is some well-crafted scrapers that enable curvature continuity during the shaping of the scrolls along their length. The scrapers work well in both spruce and maple. (We have an excellent set of miniature scrapers to meet this task, and I've listed them in this month's product section.)

Note in the photos that the peaks of the scrolls feather-off to nothing as they approach the backboard and soundboard. Also, study how the peak of the scrolls terminates as it reaches the scroll's button.

Q: I've been checking through wood books for Adirondack red spruce to learn more about where it grows and so on, but I can't find it. Is there some other spelling than the one used for the Adirondack Mountains?

A: This is a great question, and it comes up often, and yes, you are spelling "Adirondack" properly. Actually, there is no wood species named "Adirondack red spruce" it's just "red spruce" (Picea rubens). The wood is plentiful in the upper elevations of the Adirondack Mountains, a mountain range that runs through New York State, and around the lake regions (Lake Placid, Lake Saranac, etc.). The highest peak is Mt. Marcey at 5,344 feet tall.

Red spruce grows abundantly in Adirondacks and flourishes in the climates of that region, with most stands growing from 100' to 150' tall. Red spruce weighs about 27 pounds per cubic foot, has reasonably close grain as a result of slow growth in its climate, and is whiter than Sitka spruce in appearance. Red spruce is an excellent choice for mandolin and mandola soundboards.

Several members of the spruce (Picea) family have been given color names including silver spruce, white spruce, black spruce (from South Dakota) and yellow spruce. While Gibson reported in their early literature that F5 mandolin soundboards were crafted from Norwegian spruce, corporate documents actually refer to procurement of yellow spruce from Virginia; a resource of the Appalachian Mountain Range that borders the Adirondack mountains and runs from northeastern U.S. down through Virginia and Tennessee and into Georgia. Yellow spruce has a smaller girth than red spruce, but it is plenty wide enough for mandolin and mandola soundboard halves.

Have a question? Be sure to send it in and we'll answer it in an upcoming issue. We won't post your name, and chances are, if you have a question, someone else probably needs the same answer!