Gaetano Guadagnini Guitar - the Old and the New

      

I recently finished a model of an 1831 Gaetano Guadagnini guitar for a Toronto client, based on the original that I restored in 2016. Since we live in Montréal Susan and I took the train to Toronto. Lucas Harris, the owner of an original Guadagnini invited us to stay with him and his wife, Genevieve. This was a wonderful arrangement as the four of us were able to compare the original and the copy along with an enjoyable visit with old friends before I delivered the guitar.

 

Going back more than a year ago, Lucas played a program where he used his restored Guadagnini, shown in a earlier photo. A young guitarists was in the audience and was fascinated with the appearance and the tone of the guitar. After the show he got my name and email address and shortly after we began to discuss my building him a copy.

 

    Before I started the Guadagnini several months passed while I finished another instrument. Then, it was like I waded into deep water without knowing how to swim. The geometry of the guitar is the source of the problem. It is totally different than the baroque, romantic and modern guitars that I have built. 

The 3 mm thick top of the Guadagnini guitar is bent laterally downwards along a centerline forming an arch that is 7 mm high at the lower bout. The 3.5 mm thick back is also bent to the same degree of arch in the same manner.  The back also slopes toward the neck joint making the depth of the body 20 mm less, from 85mm to 65mm. I recognized that shaping the top and bottoms of the side ribs would be difficult because their heights would continuously change from one end of the guitar to the other. 

It was clear that it would be impossible to assemble the guitar body in any type of standard mold or with any standard building procedure. 

Gaetano Guadagnini was a member of the prestigious family of bowed  and plucked instruments makers. It seemed  logical that he would use a violin type of low interior form that had the advantage of being removed once the side ribs, blocks and the top or back linings were added.

I settled on the form shown in the photo. It consists of two pine boards cut to the exact contour as the original guitar. When making the two-part form I insured their symmetry by screwing the boards together, banding sawing their rough contour and finishing carefully to the proper contour, checking my progress with a square. 

The shorter of the four wood strips denote and support the positions of the front and rear blocks. The two wider ones that are the same height and serve as spacers that support the thickness of the mold. Because I glued these four strips onto their positions on only one of the boards, using the screw holes that were drilled for original alinement of the two contoured boards, the mold can be assembled and disassembled with the confidence that it will retain its symmetry as the guitar's body is constructed. The finished form is 5 cm thick.

I also built a retaining form for bending and holding the side ribs.  Although I have two commercial bending irons both are shaped for the violin family of instruments I prefer bending guitar ribs on a circular surface. This setup is dangerous and I use it with extreme caution.

     

Here I had cut out the recesses for the front and rear blocks on the form and with the blocks in place and side ribs positioned on the form I glued the ribs to the blocks. 

The contour of the waist is maintained during this procedure with the use of a contoured blocks, in this instance, a block was necessary only on one side of  the waist. It was held in place with rubber bands passed over a dowel let through holes that I had previously drilled.

 

    

The feature that defines Guadagnini's guitars is the highly arched top and back

When I removed the back of the original 1831 Guadagnini I made a curved form to hold it to its proper curve. I copied the curvature of that form and produced this concave sanding board. With the guitar frame in its mold, I proceeded to rub-sand the arch into the top surface of the guitar's frame. 

Before I could contour the bottom of the guitar frame I had to slope the side ribs from back to front. As an aid in insuring that the proper slope was maintained and that both sides were on the same plane .

I made a sloped stick with the desired slope and screwed it into position. Then I was able to return the frame to the concave sanding board and sand the bottom of the frame to the proper curvature.

     

The linings in the original Guadagnini appeared to be spruce. Making and installing the four linings was a lengthly procedure. 

They are 10 to 12mm deep and 3 to 4mm thick. I cut extra deep spruce strips from a sitka spruce board. Although I soaked them in hot water they fractured when I tried to bend them to the tight contour of the guitar's waist. I made forms, shown in the accompanying photo and eased them into them into shape using the violin maker's bending iron and a bending strap.

Since the side ribs very in depth on the top surface by 7 mm and the depth of the side ribs fall 20mm from the tail to the to the neck joint I find it easier to clamp the deep linings into place with the tail end just proud of  of the height of tail block for both top and bottom, clamping them securely to the side rides. The linings overhang the side ribs going from tail to the neck joint. Reaching between the clamps I marked the top surface of the linings. I dismantled the assembly and marked the bottom of the linings 11or 12 mm from the top line. Then I trimmed the bottom of the lining to its depth line and glued them in place, being careful that the lining was continually proud of the side rib. I repeated the procedure for each piece of lining. I finished the procedure by rubbing both top and bottom on the concave sanding board.

I often assemble 19th century guitars by shaping the braces, letting them into the linings and gluing them. With this guitar I followed the same procedure but I shaped their arches on the concave sanding board.

I glued the top and back separately, under tension, using  screw clamps that I made for a cello that I built many years ago.

The protruding tongue of the soundboard is visible in this photo. It retains the arch of the soundboard which is important because the fingerboard is radiused and the tongue takes on the soundboard's arch during this procedure.

 I didn't photograph a number of steps in the construction of this guitar so I will skip ahead to the nearly finished guitar to focus on and explain the features and their importance.

First of all, the historical guitar has a plain appearance. A thin band of ebony is glued to the inside edge of the sound hole and another ebony band is inlayed a little distance from the sound hole. The edge binding of the sound board is equally simple with a single 2x6 mm band. There is no binding on the back.

If you are curious, the lute is an old Kaiser theorbo that I built in 1997-much in need of repair.

At first sight the Guadagnini bridge is certainly odd. It is also fairly large. It measures 220 mm wide and 20mm front to rear, 14mm high on the bass side of the tie block and 12mm high on the treble side. The string holes are 6.5mm from the surface of the sound board. The wings are scalloped to a height of 3mm. The bottom of the bridge is caved out to match the arch of the  top.  The guitar retains the baroque feature not having a saddle by which individual strings can be tonally compensated, although Viennese guitars of the same era did. During the baroque era moustache bridges we an aesthetic necessity.  But Guadagnini ignored the fancy aesthetic approach in favor of a functional bridge that supports the arched top. In the earlier photo note that there are no braces in the lower half of the top. Even though the highly arched top offers a lot of rigidity Guadagnini obviously felt that a little extra was needed. The sturdiness of the bridge provides that. There is an element of fluidity to the design as the arms are scalloped and all surfaces are gently rounded. The rear platform blends into the style and the notch allows the arms to function independently.

The guitar has twenty one frets. The first eleven are made of bone with ten ebony soundboard frets. The bone frets are 1.5 mm wide and laid in slots cut in the fingerboard. Although the finished fret board is radiused I started with a flat board. Cutting the 1.5mm wide slots wasn't a problem. The saw blades that I use in my miniature table saw are conveniently .75mm thick. I glued two blades together so cutting the slots turned out to be a simple task. I glued the slotted board on the neck and planed and sanded it, creating the proper radius.

The frets are made from nut and saddle material that I cut and sanded to their finished dimensions.

The placement of  the soundboard frets were chosen by marking their theoretical location and then verifying the location with a guitar tuner. 

The original Guadagnini is finished with a deep reddish brown spirit varnish applied with many applications. I remembered this from having restored the chipped finish on the original.

I achieved a similar finish using lacquer finishes from Oxford Guitar Supply. The colors I chose match the colors used in sunburst finishes. I sprayed multiple coats of transparent Iced Tea and Tobacco Brown, alternating one after the other until I was satisfied. 

Priam and I found a quiet lounge with good acoustics at U of T for him to try his New Quadagnini.

The guitar is strung with a set of Aquila Gut and Silk 800 and fitted with ebony tuning pegs.

By the way, LF Edizioni has published a book, The Guitar in Italy, that features many guitars by this illustrious builder, with beautiful photos, interior views and measurements.  The text is both Italian and English.

                                                   All Photos by the Author