 The Clarinet BBoard
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Author: Ruby
Date: 2002-07-12 13:31
My daughter's resin Selmer clarinet has a crack or scratch on the inside that runs a cm or so on either side of a keyhole. I think it might be a scratch from the exposed metal end of her pad saver, but I wanted to ask you guys if resin clarinets ever do get cracks (when not used as baseball bats, etc!). Thanks
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Author: David Spiegelthal
Date: 2002-07-12 13:47
I've never seen a resin or even hard rubber clarinet or mouthpiece crack as the result of environmental effects (changes in temperature and/or humidity) or aging --- every instance I've seen resulted from avoidable mechanical damage.
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Author: Fred
Date: 2002-07-12 15:52
"avoidable mechanical damage" . . .
Is that a polite phrase for being dropped from the football stands?
When I was in school as a chemistry grad student, "product loss due to mechanical error" meant we spilled it or accidently poured it out. Ain't words great?
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Author: Gordon (NZ)
Date: 2002-07-12 16:05
Yes. I have seen several Armstrongs split almost right around then instrument. All in the same place. I suspect the thumb tone hole insert was too tight a fit, so when in cold weather the plastic tried to shrink more than the metal did, the plastic couldn't, so it split instead.
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Author: Bob
Date: 2002-07-12 18:18
Personally I dislike use of the term "resin" to describe non-wood and non-metal horns. I prefer the word plastic which clarinet makers avoid because it sounds cheap. Plastic horns can crack and some of the causes are the same ones that result in cracks in wood clarinets. Gordon describes one type.
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Author: David Spiegelthal
Date: 2002-07-12 20:07
Bob,
Hard rubber is non-wood/non-metal, but I would not call it a 'plastic' per se. Certainly its thermal properties, mechanical properties (toughness, flexibility) and machining properties are much different than true plastics such as PVC, ABS, and the other materials currently used in student-grade 'plastic' instruments. And many professional-grade clarinets were made of hard rubber until maybe the 1960's --- I play a few of these on a daily basis. I have a Kohlert advertisement from the late 50's showing that their alto and bass clarinets were available in both wood and 'ebonite' (hard rubber) versions (same design), for about the same price. Personally, I've found that vintage hard rubber instruments are in better condition and play better than the same instruments from the same era in wood. Hard rubber seems to be in better condition than wood after 50 years or more. The point I'm trying to make is that hard rubber is a different animal than 'plastic'/'resin'.
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Author: Bob
Date: 2002-07-12 23:48
Dave: It's partly a matter of semantics I guess. The two plastics you reference are thermoplastics. "Bakelite" and, I believe, "hard rubber" are thermoset plastics.
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Author: Dee
Date: 2002-07-13 04:04
Hard rubber is NOT plastic or bakelite. It actually is rubber but processed in such a manner that it is a hard material rather than a soft one.
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Author: Karel
Date: 2002-07-13 06:21
Gordon, I think metal will shrink and expand more, and more rapidly than the surrounding plastic, so would not hot weather be the bigger problem with the metal forcing the plastic to crack?
Karel
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Author: Gordon (NZ)
Date: 2002-07-13 06:30
Not true, Dee. The term "plastic" is a very general one.
From Websters on-line:
"Main Entry: 2plastic
Function: noun
Date: 1905
1 : a plastic substance; specifically : any of numerous organic synthetic or processed materials that are mostly thermoplastic or thermosetting polymers of high molecular weight and that can be made into objects, films, or filaments"
This perfectly describes hard rubber, an organic material which has been polymerized using sulphur and heat to become a thermosetting polymer. It is also called ebonite. Ebonite is differentform Bakelite, which is made from phenol and formaldehyde.
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Author: Dee
Date: 2002-07-13 11:45
Ok, Gordon I will grant that. However, in "common speech" so to speak, plastics are normally considered to be the synthetic materials, of which there are a wide variety with dramatically different characteristics.
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Author: Bob
Date: 2002-07-13 12:03
Gordon..thanks for the technical support. General ignorance of lay persons regarding such matters is just what the marketing people who use common terms love. Although Websters is a good reference for general terminology it only suffices for technical ones. I used the term "Bakelite" (General Electric) as a catchall term. "Phenolics" are thermoset plastics and Bakelite is the most popular term albeit almost extinct in technical usage today. Most phenolics (phenol formaldehydes) contain fillers of various types...formerly asbestos,for example. Hard rubber is even an older thermoset than Bakelite and a perfectly good material as you point out....and the term describes a whole family of compositions.
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Author: Bob
Date: 2002-07-13 12:11
Hmm..I wonder what synthetic materials are. Resins are naturally occuring materials but some are manmade.
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Author: kenabbott
Date: 2002-07-13 14:52
My old plastic Bundy clarinet developed some cracks.
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Author: Terry Stibal
Date: 2002-07-13 20:57
Rubber is a "natural" 'plastic', which can be 'set' through the use of sulphur and heat into a 'solid' form that won't change as the temperature changes. As such, it was the first 'plastic' substance (organic, moldable, set in its shape) that came down the pike...or so my organic chemistry experience in the petrochemical industry has taught me.
However, it's not normally thought of as a "plastic" these days. Use of the term "resin" also clouds the issue. Resins are fluid substances that harden into solid material, cf pine resin. So too are most thermoplastics. Thermoset plastics as discussed above (of which group the rubber/sulphur mixture is part) take their form when heated, and then don't change again when additional heat is applied.
But, where do you put something like ebonite (which contained lead as one of the ingredients) or Buffet's "Green" instruments, whicb contain wood dust mixed with the thermoplastic resins?
And, I believe S. Bellison played an ebonite clarinet to the day of his death. No slouch there in the professionalism department, correct?
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Author: Dee
Date: 2002-07-13 21:10
The material used in Greenlines would simply fall in the category of "filled plastics."
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Author: Rene
Date: 2002-07-14 08:19
It is well known that plastic of almost whatever kind ages. Reasons are sun radiation, which can really demage it, and chemical influences. Modern plastics like rubber for wheels is protected against radiation, however, but not eternally. Though I tried to find out, I found no information about the aging of Greelines or B12. I guess, they last a very long time, longer than the keywork anyway. I guess I simply replace my B12 when the times comes.
Is there an English term like the German word "Kunststoff"?
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Author: Bob
Date: 2002-07-14 14:31
I guess no one of us knows it all. My impression was that Greenlines utilized epoxy resins which, I thought fell into the classification of "thermoset" even though they don't require heat to cure...and that they were composed mainly of wood particles with only a relatively small percentage of epoxy. As such, some would probably argue that they are not "wood filled". The materials technology lore and literature involving clarinets (and musical instruments in general) is filled with misinformation the purpose of which was and is to protect trade secrets. This BB does a great service to all "who would like to know"....the facts.
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Author: Gordon (NZ)
Date: 2002-07-15 13:11
I think you're right about the epoxy being thermoset, in that when you heat it it does not melt, but instead, breaks down.
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