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Rehairing cello bow
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The violin wouldn't be much without a bow, and yet until last century it was
considered almost an accessory along with the case and tuning fork. Having said
that, there have always been bows of exceptional craftsmanship and beauty
admired by those with eyes to see.
The development of the violin bow to it's modern form was perfected by Franois
Tourte (1774-1835). Trained as a watchmaker, he took to bow making as did his
father and brother. After a painstaking search he came to the conclusion that
pernambuco was the ultimate material for bows given it's weight, strength and
elasticity. Pernambuco was used in early times as a colorant for dyeing fine
chlothes and was then called Brazil. It grows in South America and the country we
know as Brazil actually got it's name from the wood and Pernambuco is in fact a
region in Brazil.
Until 1775 the bow's length and weight hadn't been established as standard.
Working on the advice of famous viruosi such as Viotti, Kreuzer and Rode, Tourte
introduced many features still used today and established the optimal length of
the violin bow at 74 0r 75 cm. in all, the viola bow at 74 cm. and the cello bow
at 72-73 cm.
Bows are generally made by specialist bow makers although some violin makers
have made bows as well. One of the tasks which a violin maker is trained in
however is the re-hairing of bows. Rehairing a bow is a time consuming and
troublesome job. The main reason for this is that to rehair a bow properly without
damage requires lot's of patience and skill. Too many good bows have been badly
damaged by people who have learned bow rehairing from a book and think that it
might be a lucrative way to watch television. Bows should be entrusted only to
trained professionals. Among the worst of the damage we come across are:
Split heads and frogs from forced wedges.
Scratched and indented metal fittings and pearl.
Distorted stick shapes due to uneven tension.
A bow which is being used regularly generally has to be fitted with new hair at
least twice a year. Over-used hair has lost it's capacity to hold the rosin properly
and the player will notice the bow's lack of efficiency to produce a good tone.
It is often heard that horsehair for bows must be quite white and exceptionally
smooth. While it is true that irregularities in the hair's structure can cause noise,
hair is a natural material and is seldom perfect. Completely white hair is very rare
unless it has been bleached. The hair's whiteness is not neccessarily it's most
desirable attribute. Often the finest hair is anything from light-beige to butter
coloured. Bleached hair is generally brittle and should be avoided as it doesn't last
very well. Fine bowhair is exported from Canada, South America, Australia,
China, Japan, Hungary and Russia.
The thickness of horsehair is around 0.04mm and it is entirely made up of dead
cells which have been converted into a protein called keratin. Keratin is the
favorite food of Anthrenus Museorum or the museum beetle, the larvae of which
feed on all kinds of animal hair. If you should come across such a creature, don't
panic. It is a very slow animal and can easily be brushed or hoovered from a violin
case. Cut out the old hairs and burn them as well as treating the case with a
common insecticide that kills larvae. These larvae detest sunlight by the way so an
old violin case with half eaten bow is well kept in open sunlight for a while. The
surface of the hair is covered with scales overlapping away from the "horse end" of
the hair.
The most important characteristics of a good bow for the player are:
Ability to sustain tension on the hairs without having to tighten the screw
too much.
Ability to maintain this tension and being flexible without the need for
unneccessary weight.
A nice well shaped cambre right to the tip of the bow, which results in the
stick touching 2/3 of the length of the bow from the frog, when the frog and
head are resting on a flat surface and the bow is under no tension.
The amount of hair to fit into a bow depends almost entirely on the bow's build and
style decided by it's maker. Although it is often said that a violin should have ca.
150 hairs, a viola 175 and a cello 175-200, this varies tremendously as each bow
has it's own size of mortice in the head and frog and every bow has a cambre and
graduation which tolerates a certain amount of hair.
Rosin is what makes the bow stick to the string until it slips back in a continual
cycle which generates the bowed sound. It is made of colophony-the residue from
the distillation of turpentine. It comes in various grades depending on the type of
distillation. Pure colophony is far too brittle to use on it's own for violin rosin and
makes an unpleasant scratchy sound. Therefore it is generally mixed with other
substances to modify it's consistency. Most rosin will contain small amounts of oil
to plasticize or soften it and sometimes there are additions of alkaline solutions to
neutralize the colophony which is quite acid. The acidity of colophony can be a
hazard to the varnish if it is allowed to build up on the instrument.