REPLACING BOW HAIR

A couple of weeks ago, a  customer of ours,  who lives in Vienna, called me  to tell  that she was   by a great French master  working  in her city that , after having replaced the horsehair,   said that  her bow was crooked and that this problem could not be solved  because the material used was not seasoned enough. A cold shiver went through my back. The wood we use is of course not fresh but seasoned and of a high quality, but you may also understand that when a craftsman, especially French, let you know such a thing it  means that the bow moved in an  abominable way. When  the bow came back to us, we felt reassured. The bow  actually moved, but the fault was not ours, but because of his  abominable rehairing.

In this particular case, the hair had not been properly stretched, and there was not the same  tension on both sides of the bow. You see, a violin bow stick is longer than 70 cm and its  diameter slightly exceeds  8 mm at its widest point, so  if hair is  more stretched on one side, the bow will have the tendency to move in that direction. We can see the same effect on a gig, if  the tension on the harness is the same, the horses go straight, when you  pull one more than the other, they turn   in the direction of the  increased tension.

Photo 1
 
So if you collect a bow after rehairing and find it  has become crooked but before it was not like this,  try to  feel the tension of the hair from both sides  with your  thumbs (Photo 1), and if it is not homogeneous, you have to  redone  it , or better , change craftsman.

 Photo 2

Photo 3                                                                                           Photo 4
     
Another important aspect of the reharing is the combing. If the hair is  mixed and twisted the adherence will not be uniform , and inevitably this will cause unpleasant noises. To determine if the hair  is  properly combed it will be useful  to separate a small portion with your  index finger (Photo 2), and let it run  along the stick until  the head. If the reharing  is properly carried out (Photo 3), the adherence  will be perfect, otherwise some sound problems will be evident (Photo 4).

 Photo 5
 
When the hair is  just fitted, even if the craftsman can do his  job, they  do not have a uniform tension, some are more tense than others. That's why you need to wet them,   let them in tension, and after it finish them with fire. To check if the reharing has been  properly carried out, turn the screw on the button until the hair  begins to be tense , and holding the frog with your  right hand, slam  the head on the left side  (Photo 5).

 Photo 6                                                                             Photo 7

If the reharing has been properly finished, it will appear  as in Photo 6, otherwise it will look  like in Photo 7.

Photo 8

Another thing to take into consideration  when you make a reharing is the direction of the hair. The horsehair is same as our hair, just a little stronger  and with a scaled surface (Photo 8). When you carry out a  reharing,  in order to obtain the best results, it is essential to  mount the hair with the scales towards  the head. This will increase the grip at  the tip, and it  will  easen  the attack on the string  in the most uncomfortable position, where the weight of the arm helps less. Checking  if the hair is  mounted in the right direction is very simple,  you just have to watch its  color. The end of the horse tail is darker than the hairline, so if the hair is properly mounted,  those ones near   the head will be darker than those one by the frog.
 
Another important element  is the amount of hair used. Unfortunately, to determine whether the mounted  hair quantity is too low or too high, you need the  expert eye of the bow maker. The musician can nevertheless  hear the sound effect. If the quantity is low, the  sound will come out  as  very thin, on the contrary if it is  too much, this  will  act as  a  damper . In this way  we have disproved the legend more hair = more sound.

Small note for bass players:
As you know, on  bass bows are assembled using  black hair, the reason is because even if it is  less flexible than the  white one, it  is thicker and stronger, thus ideal to get vibrations from strings with such a big diameter. But the white hair still retain  its beauty even in this instrument, and for this reason bass players, perhaps trusting  someone's suggestion, ask very often for a rehairing with black and white hair .

WHAT A WICKED CHOICE !
The hair, black or white, is very sensitive to moisture,  it absorbs water and releases it in accordance with the percentage in the air. This is not a problem if the hair is all white or all blacks, the hair   will become shorter or longer, but the combing will not be affected.  If the hair  is a  B&W  mix, the comb  will be quickly damaged  and you must change it. Both types of hair have  in fact a different elongation coefficient to  moisture, so when  the  change becomes significant, for example by  passing  from  a  90% (Cremona)  to a 70% (Livorno), the hair will get ruffled , with a consequent   loss of adherence and attack.

Of course, these problems can be solved, it was enough to make a reaharing strictly  following all rules   and the bow  of our customers came back in a  perfect way. But changing the hair can also become a highly destructive or disabling operation for the bow. Next week we will see how this can happen.

So long
Paolo