By Kenny Hill
Rosette Making, A Real Labor of Love
From ACOUSTIC GUITAR, July 2001
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One of the first things a guitar maker has to confront is the rosette. It's one of the most in-your-face visual elements of the guitar, often the first detail a client will comment on. It's a purely decorative feature, and if hand made, it's the most time consuming task in the making of a classical guitar. A lot of uninitiated folks ask if it's a decal. Nothing could be farther from the truth.
The fact is, a traditional style mosaic rosette is made up of hundreds, or thousands of tiny squares of colored veneer in intricate design patterns, like needlepoint or pre-electronic pixels. This graphic centerpiece is outlined by pinstripe lines that are also made of veneer, cut into strips and wrapped together to make concentric circles. There are many painstaking steps in the preparation of these elements, which are either assembled directly into a prepared soundboard, or made separately in a mold and later inlaid as a unit. Either way, it's time consuming, detail oriented, and labor intensive.
The essential design element of a classical rosette begins in the middle with the mosaic tile section that makes up the most pictorial feature. After that come the inner and outer rings, which are usually made up of many black, white and colored lines, often including another, simpler geometric mosaic band as a part of those lines. In the traditional construction method, the rosette is built and inlaid in stages directly into the blank soundboard, first the mosaic, then the inner and outer bands.
Making the mosaic tiles is a couple of days work in itself. It is a dizzyingly clever process, and without clues I don't think you could guess how it's done. The person that evolved this process must have felt pretty smug. First the graphic design is drawn on graph paper to convert the graphic idea into squares, usually between 9 and 13 squares per side, with the finished squares being about .5mm (.022"). Each vertical line must be isolated in the graph, looking at it like a bar code. For each of those vertical lines from this disassembled graphic idea, a kind of club sandwich of veneers must be made: for instance white-white-black-black-red-black-white. These stacks are smeared with glue and clamped together, usually all between some boards, so that they come out exactly the same thickness. After the glue is completely dry these stacks are sliced lengthwise into strips. These lined strips must be finished down to the same thickness as the veneers you started with, so the little cross sections will be square. This is usually done with a sander, but can be done with a scraper, and I've even seen it done quite easily with a sharp block plane.
Are you with me so far?
Now that the vertical graph lines are made into assembled veneer strips, one of each pattern is arranged to make the graphic design in cross section. This is when you start to be rewarded for all of the wooden alchemy. There it is, your original idea, transformed into little teeny squares of wood.
Next the assembled rectangular "log" must be glued together. As with so many processes along the way, this is easier said than done. With the amount of glue surface that is being smeared around, it's harder to control than several bars of soap in a bathtub, but you can find a way to keep them in place, clamp it and let it dry.
There is still another dimension to go. With this completed mosaic log you then slice it up cross cut - like slicing bread. By now this log has cost you a couple days work, so use a very thin blade to avoid waste, and slice off the little tiles at around 2mm thick. These are the pieces that get fitted together shoulder to shoulder, and inlaid into a channel into the soundboard.
This work produces enough tiles for many rosettes, depending on the size of the veneer sheets. For all this work, you had better like the design, because you will be sure motivated to stick with it for a while. I must say though, on seeing the completed circular mosaic design appear in the soundboard after all of this intellectual/geometric/mechanical effort, it's a beautiful thing.
Now on to assembly. First the three channels are laid out in the soundboard with some kind of compass. Then the middle channel is cut out, either with deep scribe lines and a chisel, or with a router. (I use the router). The tiles now have to be arranged in this channel. It's a job of fitting rectangle pieces into a round slot. Either the tiles have been pre-curved in their building process (that's another story) or you need to fit them together side by side with the small angle determined by the radius lines from the center. This isn't too bad, it can be done with a sanding block if you've left a little margin built into the tiles. When they all fit together nicely they are glued in. Any glue will do, though hide glue is old reliable.
Once the glue is dry, the mosaic ring is sanded or scraped down to the level of the top and the channels are cut for the inner and outer line bands. The cutting of these channels should clean up the ragged edges of the mosaic circle.
The inner and outer bands are usually the same design, mirrored, and often have their own little mini-mosaic pattern that is glued up in strips. It might be a herringbone, a zigzag, a checkered pattern, or what have you. This strip will need to be bent into a circle over a hot bending iron. The rest of the stripes are usually single or double veneer lines, cut into strips, and coaxed into place by the handful. It's fiddly work, and easy to get flustered, such as when the strips break, or fly out of your fingers like 52 card pick up. Eventually the pattern comes together, all of the lines are crowded into their places, and they are ready to be glued.
You can take them out, smear the little strips with glue, and try to get them back in. Problems arise when the veneers swell from the moisture in the glue. Then you go crazy, because they won't fit back into the channel. With a lot of trial and error you can learn how much looseness is necessary for a particular glue, and then the swelling actually makes everything fit tighter. It takes practice. Nowadays I fit all of those little pieces in dry, and I don't take them out again - I apply thin cyanoacrylate glue to the surface. It wicks into all of the little spaces, glues them, fills them, and hardens the whole thing up. I know, maybe it's cheating, but life is short, and I am not ashamed.
Finally the rosette is again sanded smooth, flush with the soundboard, and you get to look at the whole thing. It is exciting. For all of that work it should look beautiful. It will change again when you put the finish on and the colors all come out. It should be something to be proud of.
Of course there are unlimited variations in technique and design. I have watched Daniel Caro in Mexico make a rosette with just a knife, a block plane and a scraper - and fast, too. It's amazing. The original makers - the old masters - made their own veneers with a big wooden plane, and someone pulling on it with a rope. No matter how you do it, it won't be easy, but it could be fun.
There are other options. If you have a design that you plan to stick with, you can have your rosettes made by a jobber in Japan, or in Germany. The minimum order will be pricey, but it saves a lot of time. And of course most luthier supply companies offer a wide assortment of well made, varied, and lovely prepared rosettes ready for inlaying.
In the world of hand made guitars, the individual maker has to deal with this signature issue. Sooner or later you won't be happy with a store bought rosette that anyone can use - colleagues and competitors - and you will find the need to make your own. It's a lot of work and daunting to begin, but when it's finally done it is rewarding, and it makes the overall guitar integrated, and for better or worse, all your own.
© Kenny Hill, Felton, CA