Violin Bow Maintenance and Myths

Every once in a while I encounter information regarding care of the bow, how to rosin the bow and how a bow works. Most of what I see and hear is complete rubbish that has been handed down without question. I think many of these myths develop do to early instruction to keep students on timetables for rosining and re hairing the bow. It is easier to teach a student violinist to follow a schedule rather than use their own judgement. The problem is that the instruction on instrument care rarely expands beyond that initial training. Let's first dispel a few myths regarding the bow:

Myth: The horse hair has scales that "pluck" the string. The scales wear out and the bow must be re-haired. This may be the most prevalent bit of misinformation I see. There is the additional bit of misinformation that when the bow is re haired, the hair ends must be alternated to account for the up and down stroke.
Truth: Horse hair is "smooth and shiny." It is the rosin on the hair sticking to rosin on the string that makes the string vibrate, not scales on the hair.  The attraction of the collagen in the hair and particles of rosin are impossible to replicate artificially. It does not matter which direction the hairs face to make a sound. If scales actually "plucked" the string, there would be no need for rosin.

Horse hair strand magnified 400X
There is debate on whether the rosin melts with friction as the bow is drawn. I am not convinced this is true, but I'm not a physicist. I can make a sound with my bow with no pressure and hardly any speed, both of which are required to create frictional heat. Put rosin on your thumb and forefinger and touch them together. They stick together! Rosin sticks to itself at all comfortable temperatures without sideways friction. As to alternating the hair ends, this isn't needed or advisable.

Myth: The bow must be rosined often, even before each use.
Truth: Rosining the bow too often creates the need to rosin the bow more often and reduces the usable life of the hair. Rosin is sticky! It grabs dust and dander in the air, oil and dirt, cigarette smoke, etc. This crud accumulates and coagulates the rosin dust, preventing rosin transfer to the string. Therefor, a new layer of dry rosin is needed to cover the crud and the cycle repeats until the hair can't hold the fresh rosin anymore and it becomes a gummy mess.
Violinists often rosin the bow the same way people put salt on food without tasting to see whether it really needs salt. Usually no additional rosin is needed. Just for kicks, see how long you can go without rosining your bow after your next re hair. I guarantee you'll be surprised by how long it can go. I have used a bow that had not been re haired for 10 years and it worked perfectly. It is owned by a professional musician who performs with it regularly.
One point I should make is that the bow must be rosined properly during the re hair procedure. Powdered rosin should be applied to the backside of the hair and worked into all the crevices between hairs. (I use a make-up brush dipped in powdered rosin) The bow is then rosined normally as the last step. Theoretically, this is the only time the bow should need to be rosined. If your playing environment is relatively dust and cigarette smoke-free, the rosin will last longer. Alas, I often perform in pubs; not the cleanest place to play.

Maintaining your bow:
  • Never, ever tap the bow-tip on anything. Don't "applaud" by tapping your music stand. Just wave the tip a little in the air. Pernambuco wood has a very tight grain structure. This makes it very strong under tension with excellent "memory," but it is easily fractured. The wood can even have a deep hairline fracture that is invisible until it ultimately fails weeks after it was originally damaged. Tips have been known to spontaneously fly apart, to the surprise of the owner, not realizing the coup-de-gras occurred days before without incident.
  • Always loosen the hair after each use. This will prevent the stick from pulling to one side and requiring straightening or re cambering. Loosen it just enough to take the tension off the stick. Hairs that are too loose might snag on a bow spinner or other object.
  • Avoid the urge to rosin, but when you do rosin, apply it lightly with a few even strokes from one end to the other. Do not end each stroke by vigorously stroking quickly at each end of the bow, a common mistake (guilty!). It only takes a few long, smooth strokes to complete rosining.
  • Use only a round cake of rosin and vary the rubbing pattern to avoid wearing a groove in the cake. Rectangular rosin cakes and grooves put pressure on the side of the hair and bow, damaging them.
  • Clean the strings and wipe the bow stick after every use. Use a clean lint free cotton cloth (laundered huckcloth is perfect) that is used only for this purpose, not to wipe rosin off the violin, otherwise you will rub rosin into the varnish, damaging it. Use a second clean cloth to wipe the violin and bow stick clean of rosin dust. Pure alcohol (not rubbing alcohol, which is 20-30% water) can be used to clean the string from a special vial, but be very careful not get any on the varnish. A cloth will work just fine without taking the risk of dripping alcohol on the varnish.
  • Take the bow out of the case first to avoid knocking it while one hand is occupied with the violin. It's easier to turn the bow spinner, carefully remove the bow and then lift the violin out of the case. If you have a shoulder rest, put it on the violin first and set the violin down in the case before removing the bow. When finished playing, replace the violin in the case first and then place the bow in the holder.
  • There are many rosins on the market with various recipes and are perfectly fine to use. The use of dark or light rosin is entirely the musician's choice, however I reccomend Salchow rosin which is simply pure rosin with no additives. Several rosin recipes have metal additives such as gold. This is more marketing than science, in my opinion, and there is little evidence to prove that these add to the performance of the rosin to justify the additional cost. In fact, the metals in the rosin dust shorten the life of the hair and damage the violin varnish through its abrasive effect.
Re-hairing: Apart from bow makers, many violin shops view bow rehairing as a necessary evil, but it is a required skill to master. A shop's reputation is often determined by the violin professionals ability to re hair a bow and is likely the shop's most requested service. Make sure your luthier has put forth the required effort to learn this skill properly and gives it the same diligence as any other instrument repair. The easiest way to find out is to ask about the materials and methods used for each bow re hair.
Only unbleached hair should be used and it will have an off-white color. Though it makes the hair whiter, bleaching weakens the hair and is done to even out the color of lower quality hair.  
Cross Section Through a Bow Frog (Click to Enlarge)

The plugs should be cut to perfectly match the new hank of hair. Even a few hairs difference will affect a perfect fit. The mortise should never be filled with rosin to "make up the difference" in the fit. Pacific Coast Maple (soft maple) is often used for plugs and ferrule wedges, however best practice is to use a softer wood such as yellow poplar, basswood or beech for the plugs and basswood for the spreader wedge. These softer woods lessen the danger of "blowing out" the tip or frog with undo pressure on the mortise walls. 

When your bow is returned to you, try it out before leaving the shop. Check the balance, etc. to make sure everything feels right. Look to make sure the hairs are evenly combed and that the tension is even throughout. No hairs should cross over other hairs. Lastly, if there is a problem that needs correction, take the bow back to the same professional. No matter how skilled, no one gets it perfect 100% of the time. A reputable professional will happily redo the work at no charge if there is a problem due to a fault in the re hair. A shop's good reputation rests on this, so give them the opportunity to make it right and make you happy!

For a more technical explanation of how the bow works, click this link to a transcript of Norman Pickering's lecture to the 1994 SCAVM Violin Making Symposium, "How the Bow Produces Sound from a String"

Also be sure to look at Strings Magazine editor Erin Shrader's excellent article  "Rosin: A Sticky Issue" at the blog "All Things Strings."

-Sir James Beament; The Violin Explained: Components, Mechanism, and Sound; 2001. (This is by far the best book available that explains very technical information in a entertaining, accessible and witty manner. A must for any violinist's or maker's library.)
-Norman Pickering; The Violin World, 2003. (A short, delightful read. Norman Pickering is the violin making world's pioneering scientific guru. He has shed light where there was only darkness!)
-The Conservation, Restoration and Repair of Stringed Instruments and Their Bows -Volume 3:
 Edited by Tom Wilder- 2010
-Karl Roy; The Violin: Its History and Making, 2006. (Pricey, but the most complete volume on the violin family of instruments ever published. )
-Erin Shrader; "Rosin: A Sticky Issue", Strings Magazine Feb. 2011.
-My personal notes from a workshop taught by Lynn Armor Hannings, Bow Maker at the University of New Hampshire's Violin Craftsmanship Institute- June 2011.