First of all, let's start with the rank beginner. Usually a new student will purchase a fiddle outfit that comes with the case and bow. Most beginner outfits come with very cheap bows. Some of these are okay, and some of these are not okay. Here at The Bluegrass Shack, I end up replacing about 1/2 to 3/4 of the bows that come with our beginner outfits. I do this at our expense, and I check every bow before it leaves here. I go so far as to rosin up the bow and play the fiddle with the bow. What do I look for in these inexpensive bows? I look for camber, warping, proper function of the frog (tightening/loosening mechanism), condition of the hair and whether it's real or synthetic, and general condition.
What are these things I mentioned and what do they mean?
CAMBER - Camber is the curve of the bow. It is important that bows have camber, which is different from a bow having a type of curvature called a warp. Good camber in a bow will allow the hair to touch the stick when the bow is in a loosened position. (Yes, you need to tighten the bow hair to play, and loosen the bow hair when you are done playing. We'll talk more about that in a minute.)
This picture shows a bow with good camber. Notice how the hair touches the stick in the middle of the bow.
I check for camber in a bow without hair by placing the bow on a straight surface and making sure that the middle of the bow touches or nearly touches the flat surface. For this test, the frog has to be on the bow.
Good camber (the shadow looks like hair, but there is not any hair on this bow) - You can see how the stick touches the flat surface.
Insufficient camber - You can see how the stick does not come even close to touching the flat surface:
WARP - A warped bow is one that is curved from side to side. You can check for warping by sighting down the bow from one tip to the other tip. It should be straight all the way down.
Here is a bow that is completely straight with no warping:
Here is a bow that has a warp in it:
FROG - The frog is the black square part that is attached to the end of the bow that you hold. There is a threaded fitting that goes into the end of the bow that allows the frog to move back and forth. This either tightens or loosens the bow hair, depending upon which way you turn the knob. You should be able to loosen the bow hair so that it is completely slack and can touch the stick, and you should be able to tighten the bow so that there is at least 1/4" between the hair and the stick.
This is what the frog looks like when it is removed from the bow. You can clearly see the mechanism for tightening and loosening the bow.
Here is a picture that shows all the different parts of the bow. You can click on the picture to enlarge it if you have trouble reading the labels.
This is what a properly tightened bow should look like. The hair in the center of the bow is about 1/4" from the stick.
This is what a bow that has been OVER-tightened looks like. Notice how there is almost no camber left in the bow.
Overtightening a bow can cause a number of problems, the most severe being warping or actually breaking the stick. Overtightening can also cause premature breakage of the bow hair and loosening of the wedges that hold the bow hair in the bow. The most common thing I see with the overtightened bow is that one of the wedges comes out of the bow and then the bow hair won't tighten, or it falls out completely.
HEAT can also cause a bow to warp, even if the hair is completely loosened. Don't leave your instrument in a hot car or directly in the sun!
The cheaper the bow, the easier it is to warp. This does not mean you can't use a cheap bow and that it can't be a decent bow that lasts a long time. It just means you have to take care of it!
THE BOW HAIR - Unless you are allergic to horse hair, you want to make sure that your bow has real horse hair in it. Real hair holds the rosin better and is not as slippery as synthetic hair. If there is no rosin on your bow, it will not make a sound when you pull it across the strings.
It is not uncommon for there to be a few loose strands of hair in a new bow when it is tightened. If they bother you, cut them off. There shouldn't be a lot of them. Don't pull the hair out. Since the hair is held in the bow by wedges, pulling the hair out can cause the wedges to become loose which can result in all the hair falling out immediately or prematurely. Any time you get a broken hair, the same applies. Simply cut it very close to both ends, but leave the ends in.
GENERAL CONDITION OF THE BOW - I check the general condition of the bow to make sure there are no cracks in the stick or the frog, and to make sure all the wedges are properly in place. You won't be able to see the wedge inside the frog, but if you look at the tip of the bow, the hair should lay pretty flat where it comes out of the tip. If it doesn't, then that could mean that the wedge is pulling out. If the wedge inside the frog is loose, then you won't be able to tighten the bow all the way. You'll tighten the mechanism as much as it will go, but the hair will still be loose.
A NOTE ON HUMIDITY AND BOW HAIR - The bow hair is very susceptible to humidity and heat. When bow hair is fitted to a bow, there is a very close tolerance to the length that the hair has to be so that it can tighten and loosen properly. The bow hair can be fitted perfectly to a bow, but if the bow is kept in a very dry environment, the hair will shrink up and you will be unable to loosen the bow hair enough to remove the tension from the stick. Likewise, if the bow is kept in a very humid environment, or if you are playing in a humid or hot environment, you may find that after a while, you are unable to tighten the bow hair any more. I always take two bows with me to my gigs, especially when I'm playing outside in the summer. When one bow reaches its limit and can't be tightened anymore, I loosen it completely and use the other bow. As soon as my bows are back in a "normal" environment, the hair shrinks back and the bows work fine.
ROUND VS. OCTAGONAL STICKS - Bows come one of two ways. Either the entire stick is octagonal, or the stick will start octagonal at the frog and will be round the rest of the way to the tip. In general, an octagonal stick will be stiffer than a round stick. Why does this matter? The stiffer the bow, the less bounce. Let's face it, a bouncing bow is not our friend! This does not mean that a round bow will always bounce, nor does it mean that octagonal sticks never bounce. Most inexpensive bows are round, so you probably won't have a choice in this as it will ship out automatically with your student outfit. If the bow has proper camber and is not severaly warped, this should not be a huge issue regardless of the expense of the bow. Bouncing can also be caused by poor technique, so think of this as an opportunity to improve your bow technique.
HALF LINED VS. FULLY LINED - This is something that does not matter at all as far as functionality of the bow is concerned. Less expensive bows are half lined. If you take a look at the picture of the bow parts that I posted earlier in the article, you'll see an arrow pointing to the back part of the frog that says "half lined." If the bow was fully lined, you would not be able to see the black part of the wood there. You would be seeing a piece of metal there instead that would continue from the slide all the way up the back of the frog to the stick.
COMPOSITION OF THE BOW (WOOD VS. NON-WOOD) - Bows can be made of a variety of types of wood and also of several other materials. Some old bows were even made entirely out of aluminum! Today, the most common materials a bow is made of are wood, graphite (carbon), and fiberglass. The main advantage to non-wood bows is that they don't warp easily and they are harder to break. In fact, it's almost impossible to warp a non-wood bow. As far as which is better, this is a personal preference. Some teachers and players prefer non-wood bows for their students. It doesn't matter to me as long as the bow works well for the student.
The main types of wood that a bow can be made of include brazil, pernambuco and snakewood. Brazil wood is the least expensive, but there are many very nice bows made from brazil wood. In general, brazil is not as stiff as pernambuco. Brazil bows start at $15 and go up from there. Most professional bows will be made from pernambuco wood. It is stiffer, harder to find, and it costs more. An inexpensive pernambuco bow will probably start around $150. They will go up in price to many thousands of dollars. Snakewood is a rarer, very beautiful wood that bows are sometimes made of. It is valued for its appearance more than anything, but its functionality is good as well. Snakewood bows start at $200 and go on up from there.
Bows are easy to break. They are very fragile. If you drop the bow, especially on its tip, you will be lucky if it doesn't break! If it drops flat, then it will probably be okay. Children sometimes tap the bow on its tip on the floor, a music stand, their shoe, etc. This will cause weakening of the bow, which can result in the tip breaking off even if the bow is not dropped. Many times, the tip does not break off immediately, but rather at a later time when the bow is tightened to play. This may cause you to think that there was a problem with the bow when it was actually misuse that caused the bow to break. Even so, I don't see this very often. (I think twice in five years out of thousands of bows.) Children also like to sword fight with their bows. Not a good idea if you want the bow to last!
So now, the million dollar question. Which bow is right for a student? I never recommend anyone purchase an expensive bow when they are just starting out. A beginning student has no consistent bowing habits and so it really won't make any difference what bow is used as long as the bow has camber and is not severely warped. (In rare cases, a student bow may be either very heavy or very light, and this can make a difference.) After six months or so of playing, a student will have developed some consistency of bowing, and at this time, the student may want to revisit the idea of getting a better bow.