How to know if rosin gone bad
I’ve had my same rosin for about 12 years and now I’m getting back to playing the violin. I was wondering how do you know if the rosin has gone bad?
When I put it on my bow it seems like a lot of rosin dust falls onto my violin.
Should I have to purchase new rosin? Also, what is the difference in cheap vs expensive rosin? Does it affect the sounds ?
If you sniff it and it smells like rancid eggs, it's time to buy a new cake.
All I can say from my experience is that I have a cake of Kaplan dark cello rosin that I've been using since the early '90s, and since about 2010 (when my cello playing finished) have been using it on a gut-string violin with no problems. It's still intact, but getting rather thin, so I guess its days are numbered. My other cake of rosin, also dark, by Pirastro, I use on my other violin. That cake will probably outlive me.
Some rosins will get a little dustier, but rosin is relatively inexpensive you could just buy a new cake if your not sure. Hopefully you have rehaired your bow since your are just getting back into playing. The hair is definitely shot and the culprit of this if you haven't.
If there's a fossilised mosquito in it, it has gone bad.
I've been playing the violin for 70 years, and have tried many rosins, but none has ever gone bad.
I had a cake of rosin that I could reasonably date to 1929. It was still working in the year 2001 when one of my grandchldren may have lost it. But it was still working OK.
Sniffing violin varnish; smoking horse hair; stealing silver bow ferrules; staying out of its pouch to all hours;
You may just be putting too much rosin on your bow. I wouldn't worry about it.
I've been working with rosin for 45 years as an industrial chemist, I play the violin, I've developed one rosin that has been on the market for several years, and I had input into the formulation of another rosin mentioned in an earlier post. I've also done several studies on measuring the differences among rosin with regard to their relative hardness/softness as measured by their glass transitions temperatures. Here's my opinion.
When you apply it underarm and see no difference from deodorant!
You can be pretty sure the rosin had gone bad if:
Dear Jo J, with lighter rosins you get more dust, this is normal. Make sure to wipe your violin top, fingerboard, and strings, with a clean cotton handkerchief, every time before you are going to add new rosin to your bow. You should only add rosin to your bow if you have a rehearsal, concert, or lesson, and otherwise whenever you notice that the bow does not "grab" the string well anymore. There also exists darker rosin that has less dust, but also there you should wipe it off regularly, it is just not so visible, but it is there. So in the end it does not matter much which rosin you use. Anyway, as others have written, it does not really go bad. Typically you only buy a new rosin when you dropped your old one :-) Yes there are rosin connoisseurs and very expensive rosins, but I think this only matters for high-end violinists. All the best with the violin!
Fascinating, Tom Quinn. I await your research, but as a player, I agree with your conclusions thus far.
"That's why zipping a band-aid causes less pain than a slower peel. It gets brittle and loses adhesion."
I was thinking about this many times. And I really don't know. My friend, specialist in the wood branch (haha he is very clever building instruments and know the wood properties - but this sounds funny:)), thinks the rosin will evaporate some kind of substances inside and degrade slowly but in a matter of months or maybe few years when perfectly sealed and you have a small surface with contact with the air. Also, we were talking and discussing that already oxidized surface can seal it a little bit more (there are fewer holes and pores under a microscope) so I think that not used rosin in a shelf has a longer lifespan until the musician will disrupt the surface. Also, there is this effect during usage, we are still peeling off the oxidized particles and reach the deeper better part.
"Since the stick/slip of the rosin on the string happens at the same frequency of the note"
Jean, that's largely true, once the string has reached a steady state of vibration.
David - is that why the note sounds dull if you put too much pressure on the string? That would prevent the string from breaking free to vibrate. Thus, 'good tone' requires a consistent and accurate bow pressure (which obviously varies with contact point and bow speed).
Yes, it disrupts the cycle of the string breaking free at exactly the right time.
To illustrate string action during bowing - and the slipping process:
Tom Q -- another chemist here. Any idea what the oxidation reaction is? Looking at the structure of abietic acid I can guess, but I'd rather not guess if someone's got an answer. (I'm even less inclined to look it up.) Also is it possible that the hardening arises from the gradual loss of volatile plasticizing species (water, or a terpenoid or such)? I noticed (anecdotally -- not by any scientific means) that rosins that I melt down and re-mold are a little harder then they were when new, so I wonder if I'm driving off any "plasticizer" in that process.
Add a little vegetable oil during the melting Paul to soften it. Its great for rosin to use in those motels without any soundproofing...
I should have raised this question a lot earlier, but of course powdered rosin on a bow will oxidise a lot faster than rosin in a cake, and, as with stainless steel, we also need to ask, is the external oxide layer on the cake airtight or not? The two rates of oxidisation may make some of these arguments academic if the difference is great enough. These are all questions I don't know the answers to: I haven't done any chemistry since 1976.
Elise that makes sense. More sense than turpentine. :)
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