Restoring the octagon of a violin bow

A repair method that avoids having to rebuild the whole octagon from scratch

Lutherie

Bow maker based in Verona, Italy

Amusician brought me an old French violin bow (a Lamy, according to her) to be rehaired, but the part that needed the most maintenance was not the hair but the octagon at the frog. It was so worn that at some points it had reached the mortise containing the eyelet, especially at the corners. Many years of use and poor maintenance had consumed the wood, which was cracked in several places. This is not a particularly strange kind of wear, especially after decades of use, but not all players use bows in the same way and a lot depends on the way they hold the bow, as well as the acidity of each player’s skin.

In some previous cases, similar to this one but in even worse condition, I had been forced to rebuild the entire octagon. I had cut the original below the silver lapping to hide the joint, and inserted a completely new wood part. In this case I preferred to rebuild the missing wood.

The damaged bow

Making a spatula from a piece of bamboo

1 After removing the hair and the lapping, the first stage was to clean the cracks as much as possible, both from the dirt that had infiltrated them over the years and from previous awkward interventions to fix the wear made with various glues, which obviously hadn’t worked. In this case I used a bamboo stick sharpened with a knife to create a sort of very thin spatula, with which I applied some acetone and removed the dirt.

ALL PHOTOS ERICH PERROTTA

2 I then decided to restore the worn wood with some pernambuco shavings. I chose the closest wood in terms of density and colour that I had available, bearing in mind that the glue I would use afterwards would darken it slightly. With the plane I obtained numerous shavings of different thicknesses, so I decided to stock up on shavings for future repairs as well.

Planed pernambuco shavings

The shavings are stiffened with glue

Ready for the repair

3 I stiffened the shavings with a very diluted glue, in order to make them more easily manageable, keeping them on a piece of baking paper and then closing them with a glass plate to keep them flat as the glue dries.

Applying sturgeon glue

4 When the shavings were ready, I first inserted the thinnest ones into the cracks, using the strongest glue I had available: sturgeon glue. Then I did a sort of progressive lamination, overlapping the various layers like brickwork, to create a more compact surface.

Stretching the shavings

5 Obviously it was not possible to use clamps of any kind. So during the drying I ‘stretched’ the shavings, keeping them in the correct positions with a hard stone nib used in bookbinding.

Finishing with a file

6 When the layers reached a thickness slightly higher than the original one – verifiable by looking at the octagon from the side – and the glue was completely dry, I started to finish the new wood, first with the file, then with progressively thinner sandpaper. 

7 After the reconstruction and finishing, I touched up the colour with alcohol-soluble pigments mixed with a small percentage of wax-free shellac. I concluded the varnishing phase with several days of shellac pad varnishing. Since this process creates very thin layers, I had to apply a layer every day and wait a day for it to dry. It took around ten days to create a sufficient thickness to protect the retouches.

8b

8 Once the restoration was finished, I decided (in agreement with the customer) to protect the octagon with a layer of kangaroo skin. It’s not a solution that excites me and many musicians don’t like it because, however thin, it modifies the thickness of the stick and the support point of the right hand. In this case, however, the extreme wear to which the bow was subjected convinced us to adopt this solution.