 The Clarinet BBoard
|
Author: Bob
Date: 2002-09-21 13:42
I just acquired an older Lafayette Bb Sop. A search here indicates that L was a Bruno import. However, my horn has a metal bore liner in the top section that is a brass color. Further searching indicates that Pruefer marketed a "silver throat" horn. Furthermore,now, I wonder if there is a way to differentiate whether a horn is made from hard rubber or "plastic". My horn has a radial brushed finish. Any comments or info appreciated.
|
|
Reply To Message
|
|
Author: Gordon (NZ)
Date: 2002-09-21 14:02
Old hard rubber has a characteristic rubbery or sulphury smell and slightly green look. Most mouthpieces eventually get like this.
The smell is more obvious if the surface is scraped, say at the end of a tenon. The surface scrapings may be brown, where it has oxidized.
Heat the scrapings - quite hot - and the rubber smell is more obvious.
|
|
Reply To Message
|
|
Author: Don Berger
Date: 2002-09-21 15:18
Bob - There is an immense variety in what we generically call "plastics", so a look in dictionaries, in particular those which go into some "chemical" detail, is suggested. I'm trying to NOT go far into this "jungle", but for me, I classify firstly by "thermo-plastic" vs "thermo-setting", whether they melt/flow or just decompose when heated, examples for clarinets, are ABS [acrylonitrile-butadiene-styrene] TP vs "hard rubber" TS. Then the source of the raw materials and their chemical treatment, reactions such as "vulcanization-crosslinking" enter the picture. Then the manufacturing methods, machining vs molding need to be considered. Thats about as far as I want to go, Others, Please Help. Don
|
|
Reply To Message
|
|
Author: Bob
Date: 2002-09-21 18:21
Thanks Gordon and Don. Don, I have a good technical appreciation for the different kinds of plastics and I gave some thought about just how to word my query. Since the horn involved was made before ABS was in common use and because I know it is either "phenolic" or hard rubber I tried to keep it simple. It appears that this upper section uses the metal tube as an insert and that a simple split mold was used for the thermoset molding process. Thanks again. Bob
|
|
Reply To Message
|
|
Author: ron b
Date: 2002-09-21 18:35
I may be off the beam here, Bob, as my experience is limited to what I've seen and touched. Gordon has far more knowledge and experience about the subject than I; of that I am sure:) I've been told that old Lafayettes are pretty good.
I've found, personally speaking, that plastics look and feel shinier than hard rubber and plastics tend to chip and/or crack more readily than rubber. However, either will chip or crack under certain conditions and either will break if stressed too much.
Gordon's advice is also very good if you want to make an 'in depth' determination. Personally, I'd be content to find out how it plays before deciding whether to invest in making it mechanically sound. I know practically nothing about metal lined bores, how the expansion/contraction differentation might effect its longevity.
Fact is, I've never seen or touched a metal lined instrument. My guess is, if there's a good bond between materials, it may be perfectly all right. That would be my primary question... whether it will hold together for another few years.
|
|
Reply To Message
|
|
Author: Don Berger
Date: 2002-09-21 19:03
Bob, SORRY, I never know how to respond to such a question, and do apologise for any "talking-down", just didn't recognise that you have well above-average tech knowledge. On back I had a Schreiber & Sohn metal-lined UJ cl, believed it to be hard rubber, dull, a bit brown-green [to me quite conclusive], not much of a horn! Also have an old Conn HR [prob natural rubber heavily sulfurized], turn-of-the-century, "hybrid" model. My 1932 Selmer FB [wood] has a metal-lined barrel with about an inch extension into the UJ, not sure why!! Ron's and Gordon's comments/advice is good re: identification. Luck, Don
|
|
Reply To Message
|
|
Author: Dee
Date: 2002-09-21 19:28
Sometimes hard rubber will turn brown with time.
|
|
Reply To Message
|
|
Author: Synonymous Botch
Date: 2002-09-21 19:51
Easy enough to test with a little 800 sandpaper... give the tenon a twist on the sandpaper and look to the tailings;
Brown dust for rubber
White or light grey for composites.
If you get a whiff of your car overheating, that's hot rubber!
I love this old design, tough for the kiddies to break off one of THOSE tenons!
|
|
Reply To Message
|
|
Author: JMcAulay
Date: 2002-09-21 20:53
If you have a really good vapor degreaser handy, you could stick part of the instrument in it for an hour or two.... if the body is phenolic, it should melt away rather nicely.
Oh, wait, maybe that's not such a great idea....
Regards,
John
|
|
Reply To Message
|
|
Author: ron b
Date: 2002-09-21 21:22
Yes indeed, John. Good reminder to be careful how you clean plastic objects. Some kinds of plastic will 'melt' when exposed to (submerged in) alcohol for lengthy periods, such as overnight - while other plastics will be unaffected.
I don't believe, however, that either kind would be done harm by breath-test amounts :]
ron, "who discovered this the hard way" :|
|
|
Reply To Message
|
|
Author: Bob
Date: 2002-09-21 21:23
No apologies necessary,Don, as I often have similar problems understanding what the submitter really is after. The metal lined barrel sounds interesting as does also the vapor degreaser winner.
|
|
Reply To Message
|
|
Author: Gordon (NZ)
Date: 2002-09-22 13:18
Interesting.....
In my experience the exterior of hard rubber bodies get a dull greenish hue.
However I've jsut done scrapings from a tenon and they were definitely brown. I wonder if the brown is a reaction to enzyme attack from saliva.
Most early Chinese clarinets (Hsinghai & Lark) - and possibly current ones - were hard rubber. The silver-plated keys develop a black tarnish, supposedly from reaction with the sulphur fumes from the hard rubbber.
This tarnish probably happens to a lesser extent with any clarinet with silver plated keys if one keeps in the case and old hard rubber mouthpiece that has got smelly.
|
|
Reply To Message
|
|
Author: Bob
Date: 2002-09-22 16:16
Gordon: I don't think the brown is from saliva contact as I have some old hard rubber mps that are brown where mouth contact is not commonly made...I think it's just from contact with what's in the air...i.e. oxygen. But there's probably some oxy in saliva too.
Personally I find the idea of making a non-metal clarinet with a metal tubing bore technically challenging.
|
|
Reply To Message
|
|
Author: Dee
Date: 2002-09-22 19:11
The hard rubber clarinet that I have is brown all over on the outside and still black on the inside. The mouthpiece that came with it is brown all over the outside except where the ligature was seated. It is black under the ligature and on the interior of the mouthpiece. Since it had no case, I believe someone generally left it sitting out on a clarinet stand. In which case it is probably due to the effects of light, either visible or ultraviolet.
|
|
Reply To Message
|
|
Author: Gordon (NZ)
Date: 2002-09-23 10:57
Early wooden flutes frequently (perhaps normally) had a metal liner in the head. Perhaps it was in order to get a strong enough upper tenon, where the timber is very thin. When ithe liner corroded the timber dsplit.
The first section of bassoons often (perhaps normally) has a polymer liner which I think is normally hard rubber. This stops the bore of the timber rotting.
|
|
Reply To Message
|
|
The Clarinet Pages
|
 |
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
.jpg){kind=small}
