Monday, February 21, 2011

RECOUVREMENT or the pearl slide.

This blog has been in existence for about two months. Its proving to be hard to post regularly especially during times like last week when I’m traveling. I think once or twice a week is possible.

Before cutting the coulisse and fitting the heel, a piece of shell is cut into a rectangle and glued to a strip of ebony. Now it is ready to fit by filing an angle or dovetail on each side and gradually bringing it down until it slides in snugly against the heel. The coulisse or channel is slightly tapered which ensures a tight fit. It would not be good for the hair underneath to push the slide up. Then the other end is trimmed carefully until the ferrule can slide back on and fit tightly against the shell. But the ebony strip underneath continues on under the ferrule to prevent the slide from lifting.

This particular piece of nacre or shell is very beautiful but for some optical reason it’s difficult to record this in a photograph. When the pearl slide is fit the frog is nearly finished and only the under-slide where the frog fits on the stick remains to be done. Since the stick hasn’t been chosen I will put the frog aside for now and think further about the bow and the choice of wood.

Friday, February 11, 2011


The pearl slide slides into a dovetailed slot called the coulisse at the end of which the silver heel is glued and pinned. Techniques passed on for generations allow this to be done freehand with great accuracy using two chisels. The pearl slide is made of a thin abalone sheet glued to a strip of ebony. Originally the small silver heel was also attached to this ebony strip and formed a joint with the larger silver heel running down the back of the frog.

But later both parts of the heel or 'talon' were glued and pinned together leaving the pearl slide independent. The heels are pinned by drilling a fine hole through the silver and into the ebony. Then a piece of silver wire is filed to fit and riveted with a small hammer.

Under the pearl slide, another channel leading to a mortise is cut to accommodate the hair, which will be secured with a wooden wedge.

Wednesday, February 9, 2011


The open flanks of the frog on the early bows probably piqued the human desire to ornament things, sometimes to excess. So eyes and other inlaid ornaments were soon common on the frog sides. Tourte, once again with all his creative intelligence, is most likely the first to make the silver rings around pearl eyes. But some of his most beautiful bows are without eyes or even a pearl recouverment or slide. But the simple pearl eye is found on the greater majority of bows from every tradition.

Later in the 19th century, eyes were often surrounded by silver rings, but in this case, stylistic convention required that the button be plain silver with no ebony showing. This may well have started with Voirin and certainly Lamy used that rule. Vigneron is also a good example and Sartory followed this style with the exception of the bows he made his friend Emile Germain, the luthier. These were without eyes and stamped with Germain’s name. Although I have always avoided trading in old bows, I once had a visit to my Seattle shop from a violin shop owner with one of these bow’s in hand. He asked my opinion and I told him it was a Sartory. He later confided that he was afraid to sell it as a Sartory because its authenticity could be questioned. So he wondered if I would buy it as an unknown entity. I took it to Paris on my next trip and sold it immediately because the bows were well known there. On the other hand, gold mounted bows in this period most always had a button showing two gold rings.

To put eyes on a frog we drill a very shallow hole in the frog using a special bit we make ourselves. Then a piece of pearl is filed round to fit tightly. This is glued in place and after the glue sets any excess pearl is filed flush. Traditionally the eyes are cut out in little squares with a saw and the corners are filed or clipped off making an octagon. Then the eye is filed round and fit. This can be done much faster and accurately than one might think. However today makers often use a lathe to cut out the little eyes. Interestingly, the hand fit eyes look livelier because they are almost imperceptibly out of round.

Tuesday, February 8, 2011


The pearl-shell or nacre has long been used to decorate bows, certainly since the time of Tourte. This was normally Abalone; species in the genus Haliotis that are found throughout the world. In the early 19th century an abalone found along the coast of Brittany known as Ormeau (Haliotis tuberculata) was used but the shells were small and curved requiring much labor to make a pearl slide. This was the typical recouverment or slide still to be seen on an original Peccatte with very tight and brilliant waves. This shell is still available for restoration work.

Around the mid 19th century, a lady of a certain class was obliged to carry a fan with which dispel harsh odors in the streets or strike boorish gentleman. Fans made of delicate Abalone pearl strips were much in vogue and this Abalone came from the Far East, no doubt creating a trade in the shells. Bowmakers soon adopted this material for its beautiful hues and its use continues to this day. Delaruelle, an intrepid supplier of tools and materials to the luthiers and archetiers around Paris during the 80ies discovered a cache of this shell dating to the 19th century. For quite some time we were able to buy parts of abalone shell fans from him. He continued to supply the trade with shell until his untimely passing a few years ago.

Although the normal shell is a bluish green with some pink striping, some shells are a blaze of red and gold, the colors boiling and bubbling to the surface.

Friday, February 4, 2011

CARVING THE THROAT. The frog part 3.

To fit on the silver ferrule, a projection or tenon is cut into the ebony frog piece and this is shaped until the ferrule slides on tightly. Then the frog is brought down to the final height and length. The sides of the frog are scooped out with a gouge and then we are ready to start the ‘degorgement’ or throat. Like the head, the frog is a sculptural form defined by its function of holding a flattened band of hair a certain distance off the stick and sliding back to tension the hair as needed. Beyond that the frogs shape is defined by a combination of tradition and the desire of each maker to do something different, something a little different from the next maker. This is expressed most noticeably in the sculptural shape of the throat, the area between the ferrule and the thumb projection. The throat can be squared off and angular as in Persois’s bows or gently rounded as in Voirin’s or a combination of the two as in Peccatte’s.

The challenge of the throat’s design lies in the fact that the ferrule presents a steeply convex surface while the sides of the frog are hollowed out or concave. Then the thumb projection is steeply concave again so the throat’s shaping must gracefully traverse these opposing surfaces. In addition the continuation of the flanks of the frog into the throat can be abrupt or tapering inward to a small radius. So this simple shape bounded on three sides by the rest of the frog can manifest an almost infinite number of shapes that express the personalities behind them.

The throat is shaped with a knife and here as in the head we rely on tools that give us the measure of control we need. Once the shape is fully defined, some strokes of a needle file smooth it out and we are ready to go on. Now the frog looks complete except that there are no channels, mortise or pearl eyes and slide. The polishing will come later.

Wednesday, February 2, 2011

SILVER. The Frog part 2.

Bow making requires a number of techniques that a jeweler uses and that includes cutting and shaping silver or gold and joining them with solder. Normally we work with silver. Each nation has precious metal standards and England and the US have the Sterling system. France has had several standards over the last two centuries but for quite some time their silver has been called ‘argent premiere titre’ and it consists of 95% silver alloyed with 5% copper to harden it. Since Sterling silver has 92.5 % silver and 7.5% copper it has a slightly different luster than the French silver we use in this shop.

Gold commonly accompanies the finest work of a maker but this is not necessarily the case. All we have to do is look at the elegant silver mounted bows of the great makers Francois Tourte or Dominique Peccatte; it is often evident they went all-out to make a given bow, the stick is phenomenal. A silver bow may have been made for a great professional player who could not justify the expense of gold and indeed at the time gold mounted bows were likely destined for the nobility or the wealthy. It is also a fact that of all the precious materials in a great bow, gold is the most easily obtained. The gold is expensive but the stick is priceless. Gold also weighs more than silver; gold mountings will weigh about a gram more, which is sometimes an important consideration. But some contemporary makers consider a bow with gold mountings to be their highest grade so in this case purchasing gold mountings from them is well worth consideration.

After the rough frog piece has been prepared, we make the ‘passant’ or ferrule that contains and spreads the hair. According to Bernard Millant this ring was invented by Francois Tourte in 1782 or 1783 to accommodate the demands of Viotti and Kreutzer who were troubled with the hair bunching as they played at the frog. Prior to this time the frog was open with the hair coming out of a mortise in the same way it does from the head. A jeweler’s saw is used to cut out two pieces of silver, one of which is bent into an arch. Then they are heated to red-hot and soldered together to form a ring. This ‘D’ shaped ring is hammered out to shape and it is then filed to size. Now it’s ready to fit on the frog.

EBONY. Beginning the frog.

There are many living things that go into a bow but after the Pernambuco wood, the bowmaker is perhaps most thankful for ebony. This amazing wood grows initially a creamy white in color before turning after some years to a black as dark as coal. So the sapwood or exterior inch or so of the tree trunk is white and the heartwood or interior of the tree is black. Over time the wood’s pores become filled with the minerals from the earth and when the wood is polished these minerals shine in little silvery lines. The polished wood takes a luster like marble.

Ebony wood refers to a number of different species in the genus Diospyros and only a few are suitable for bow-making with a jet-black color and a tight grain. The ebony of legend, Mauritius ebony or Diospyros tesselaria, has not been exported since the 19th century. In fact it is exceedingly difficult to find ebony suitable for really fine bows. Years ago Stephane Thomachot and I bid for and won a lot of this ebony at the Drouot auctions house in Paris. It was from the estate of AndrĂ© Chardon and the crate, which had been stored in the coal cellar actually contained coal as well, which we dubbed ‘le charbon de Chardon’. Since that time it has been occasionally possible to locate ebony from Ceylon or Madagascar with the required qualities. A bowmaker needs only a very small quantity of ebony but nonetheless the conservation of these trees is of concern as the world’s forests are cleared. Replanting of the trees as we are doing with Pernambuco wood is necessary for the future.

The basic ebony piece that will become a frog is split or sawed from a larger block and worked down with a gouge and a plane. The minerals in ebony will dull a sharp tool in minutes so we have to sharpen often. When the blank is cut out we drill a hole where the ferrule will go and saw out the rough throat. Then we put the piece aside and prepare the silver for the ferrule.