Having recently completed two Torres replicas...each with its own wooden coffin case, I've become inspired to build more. This time I am really pushing the envelope - I'm using torrefied woods for the soundboard (European spruce) and the back and sides (birdseye maple)...AND...I am adding a brass tornavoz...AND...I am using Torres-like tolerances. For example, the thickness of the sides is ~1mm (or even less in several locations) and the average thickness of the soundboard, as measured in 17 different locations, is 1.5mm. These are all firsts for me.
I am quite late in posting this article, as the instrument is nearly completed - it has been strung up and played (which you can see and hear at the bottom of this article). It is called LA MADRUGADA, the dawn. I am still completing the French polishing and starting work on the wooden coffin case which I am building using Makore (African cherry) with a birdseye maple insert on the top and padauk bindings.
Using the torrefied woods for this project gave the instrument an already honey/amber "aged" look. I found both the European spruce soundboard and the birdseye maple very easy to work with and quite stable. I will certainly use torrefied woods again.
Although I normally make my rosettes "in situ", or inlaid section-by-section directly into the top, for this instrument I chose to build the rosette in another piece of spruce, trim and sand it out and inlay it into the soundboard as though it were a pre-made rosette.
The use of a tornavoz created some new challenges. While I have wanted to try building a guitar with a tornavoz for a number of years, I needed to find a way that I could remove it if necessary without having to remove the back. As it is conical in shape, not just a straight tube, I needed a way to compress it so it could be removed through the soundhole. But at the same time it needed to fit securely to the top and its ends seamed together, something normally accomplished by soldering. It wasn't until I saw an instrument by a Spanish builder featured on the Guitar Salon website https://www.guitarsalon.com/ with a tornavoz that I realized how to accomplish my goal. He used copper foil tape on the inside of the tornavoz to join the ends. Aesthetically, I did not really care for the look as seen through the soundhole (a big strip of copper foil against the brass of the tornavoz)...but I liked the idea! So, I put the copper foil tape on the backside, so as not to be visible, yet with an Exacto knife I would be able to insert it between the joined ends to slice the tape on the backside so the tornavoz could be compressed in order to remove it through the soundhole. At least, that is the theory. I have not yet tested it...and hope I never have to!
In the photos below, the copper foil tape is not visible through the soundhole. The tornavoz has a narrow "lip", or flange at the top that fits into a shallow channel in the wooden ring that secures it to the soundboard. In order to be able to compress the tornavoz for removal (if ever necessary), there are several holes into which a pincher-type device, something on the order of needle nose pliers, could be inserted to squeeze the cone into a small enough diameter to remove it through the soundhole. To facilitate this compression, in the upper left of the second photo you can see a section of the flange has been removed so the ends of the cone when compressed can overlap, facilitating the compression.
As with the other Torres replicas I build, the dark veneers used in the building of the rosette, the purfling, and in this case the Greek key motifs are all of Brazilian rosewood instead of dyed woods. The green veneers used in the "ears of wheat" of the rosette and in the purfling are dyed woods. All others are natural woods - mahogany, maple, and ebony. As per the original, the bindings, bridge, and headstock face are Brazilian rosewood.
Always a moment of truth is the routing of the channels for the bindings and purfling. For these tasks I use two separate routers, mounted on two separate carriages for the StewMac TrueChannel Binding Router Jig. The first router has a bit and bearing pre-set to rout the channels for the narrow 1.5mm wide bindings of my Torres instruments. The second router uses a modified carriage designed to accommodate a larger cutter (1 3/8") with its associated bearings to cut a much wider but more shallow channel for the wide purflings on my Torres instruments, in this case 1mm wide brown/white squares sandwiched between 12 separate veneers of black, brown, green and white measuring an overall width of nearly 6mm. Thus, the resulting cut with this router bit combination is ~7.5mm (purfling width + binding width).
April 26, 2019, DISASTER STRIKES!!!!! Anyone who knows me knows that I hate routers...I use them, but I hate them. Well, here is one example of why that is. Something I have never before experienced... While routing the channels for the purfling on the top, the small screw that secures a guide bearing to the router bit somehow worked loose and fell out, causing the bearing, which determines the depth of cut, to fall off the end of the router bit...and here is the very, very painful result. It nearly brought me to tears. No, I wasn't physically injured, but the guitar...
The only mitigating factor in this disaster is that the bearing failure occurred at a point over the end block, leaving a solid surface onto which to glue my patch. A few millimeters more and I would have had an open cavity into which to try and secure a patch.
Certainly not an invisible fix, but using some remnants from the top, I lined up the grain as best as I could. Clearly, the dark winter growth lines do not perfectly align as I did not have the precisely adjacent piece available . From a distance, however, the injury is not very noticeable...but that doesn't help - I AM STILL ABSOLUTELY SICK!!!!!!!!!
I'll be adding more photos when I am able. But, in the meantime...here is what it looks and sounds like so far (still working on the French polish). Michael Cruz performing and excerpt from Andrew York's "Yamour".