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I am in the process of learning how to rehair a bow and have looked at several Youtube videos to visualize the process before I start work on my own. In all of the videos, the luthier cuts off the old hair with a pair of scissors before removing the tip and frog wedges. If the old hair has not been obviously stretched out, one would think that the old hair would be retained to determine of length the new hair requires between the knots.
A lot of time is spent (in all of the videos except that of Daniel) in creating an elaborate knot on the ends of the hair. I would think that a 1/8" or so length of electronic heat shrink tubing would be adequate. I would still expand the hair with rosin/glue on the short ends behind the knot/shrink wrap.
If the microscopic scales on the hair are so important to bowing, is half of the hair hank switched end for end so that half of the hair would be of the proper geometric orientation for each portion of the bow stroke?
Little regard appears to be given to the comb used for removing hair tangles. I would think that a very fine comb, similar to that once used for delousing, would be optimum.
Is there any reason why white hair is used for the violin and black hair is used for the double string bass?
Without deviation from the norm, progress is not possible. —Frank Zappa
The future is already here—it’s just not very evenly distributed. —William Gibson
I don't think you need to change the direction of half of the hairs, since ultimately the rosin is what grips the strings, those microscopic 'teeth' simply cut the rosin better when you apply it and provide a pocket to store it in. But as you're bowing some of that powder constantly gets released to the full surface so it should keep your bow gripping in both directions. However I don't see any harm in doing it either, at least if you're patient enough haha (If it was me I'd probably be unlucky and entangle them while flipping half of them.. then spend half an hour separating them lol :D).
Anyway, black hair is more coarse / strong, it can hold more rosin and it has a stronger grip. Probably that's why bass players use it along with much stickier rosin. But generally for violins it's not needed as the strings are easier to get moving so generally you can achieve a pretty extreme grip even on white hair if you use a dark rosin. Though I saw Fiddlerman using a bow with black hair in one of his videos and in the comments section someone asked about it and he told them that he simply had one of his old bows rehaired with black hair since it allows him to 'dig more into the strings'
Regarding the comb :))) I can't help you as people claim I wouldn't even know how to use one lol.. But tomorrow I'm getting a haircut! (should've grown it longer.. would make for a fine bow...)
The direction of the hair doesn't matter, and most luthiers ignore it. What makes real hair much more valuable than synthetic hair is that rosin sticks to it.
You might want to try and experiment with the heat shrink tube idea before putting it on the bow. The glue may be enough to keep the hair from pulling through, but I'm a little sceptical.