David Migoya wrote:Jem, thought I'd address this minor point.
Do understand -- and unless i'm wrong -- that the ebonite of years ago had sulphur in it. This is the chemical reaction to air, sunlight and our perspiration that causes the greening effect.
It was not chemical impurities or imbalances. it was how it was made. Essentially, it was vulcanized rubber that hardened.
It was not Delrin (see the Capital letter? I believe it's a trademark, just like Xerox), which in today's world is much, much different!
Few flutes are actually made of ebonite today (if any!). They are made of a grade of plastic that is very, very different.
David, I'm well aware that Delrin (didn't realise it was a trade mark/name) is quite different from Ebonite (also a trade name, I've just discovered). No, you didn't say the Delrin goes green! Just Ebonite. I believe though, that I'm right about the "chemical impurities and imbalances" being the cause of the degradation of early Ebonite, both in colour and sometimes structurally. See the Wikipedia article below. Because it is a vulcanised rubber product, by definition it has sulphur in it. Still does today. I don't know the full chemistry (not educationally equipped!), but the sulphur/rubber+? mix is heat treated to "vulcanise" it - in the case of Ebonite to a very extensive and prolonged degree, apparently, compared to other vulcanised rubber products. Modern Ebonite made to modern chemical standards and with high-tech industrial processes and equipment doesn't degrade significantly. Quite a lot of things are still made from it. Google it and see. The early stuff did degrade because they got too much or too little sulphur, or got other impurities in, maybe in the latex, or didn't control the heating process finely enough, or whatever.
I've seen C19th Ebonite flutes (but not many, admittedly) that had gone sort of milk chocolate or milky coffee colours or even yellow ochre-ish as well as pond-slime greenish ones.
I'm not saying there aren't any, 'cos I haven't checked, but I don't know of any modern Boehm flute manufacturers working with Ebonite. We know Terry McGee has tried it - and complained about the smell! As I already said, some of the Pakistani/Indian "things" are being made from it - most notably by "Empire" from India who advertise direct sales on eBay regularly. (Incidentally, I have one of their [I think - no marks and acquired 3rd+ hand] Pratten style Eb flutes in the house, and it is tolerably well made, save for poor configuration of the touches of the Boehm-style footjoint keys and the rather crudely cut embouchure. It has a decent tone and is well tuned - better than some modern keyless ITM flutes I've come across.....!!!!!!! When I get around to tweaking the embouchure cut and shortening the foot key touches so they don't clash with R3 covering its hole, I think it could be half decent. Oh yes, and it does have a touch of the whiff of a car tyre depot about it!)
Wikipedia
Ebonite is one of the earliest forms of plastic. A hard, rigid and shiny resin, it was intended as an artificial substitute for ebony wood. It is actually a very hard rubber first obtained by Charles Goodyear by vulcanizing rubber for prolonged periods. As a result, it is about 30% to 40% sulphur. It is often used in bowling balls, smoking pipe mouthpieces, fountain pen nib feeds, and high-quality saxophone and clarinet mouthpieces. It is also commonly used in physics classrooms to demonstrate static electricity.
Hard rubber ('Ebonite' is a brand name that's not universally used) was used in the cases of automobile batteries for years, thus establishing black as their traditional color even long after stronger modern plastics were substituted. It is used in hair combs made by Ace, which survive, essentially unchanged, from the days of the US Civil War.
A Google search brought up German company SEM
http://www.sem-hitzacker.de who produce modern ebonite for the musical instrument industry, amongst other uses. Check out
EboForm on their website, especially any of our makers who want to try it! Seemingly doesn't have to be black these days, either! I didn't search further, but I'm sure there are other manufacturers of Ebonite rod stock out there.
More Googling - I've just found this useful link on flute materials....
http://www.chemsoc.org/chembytes/ezine/ ... _feb00.htm
which includes the following on Ebonite:
Rob Kingston
The first synthetic material to be used in flute-making was ebonite, also known as vulcanite. This compound, made by heating a mixture of India-rubber, sulphur and lead, together with a black pigment, was used to make flutes as long ago as the Great Exhibition of 1851, according to Rockstro. He adds that 'these instruments are now [ie in 1928] more popular in England than any others'.
In his book, Rockstro listed many advantages of ebonite over more traditional materials:
'Firstly then, in the matter of endurance it may be pronounced perfect, for it is practically indestructible.
Secondly, as it is absolutely non-absorbent of moisture no change in the dimensions of the tube ever occurs…
Thirdly, an ebonite flute invariably improves by judicious use.
Fourthly, this substance possesses just the amount of rigidity necessary for the retention of the enclosed air-column in its proper shape and dimensions…
Fifthly, this material is so bad a conductor of heat that ebonite flutes are far less affected than any others, in their pitch, by alteration of temperature.
Sixthly, its appearance excels that of the finest ebony, and it generally retains its original lustre with very little attention, though sometimes it loses its extreme blackness.'
Rockstro also noted that ebonite flutes required 'little expenditure of breath', rendering them 'peculiarly suitable for the use of ladies'. Despite this glowing praise, however, ebonite's popularity seems to have waned significantly by the middle of the 20th century.
Note: Mr. Kingston has made a simplistic error in assuming that Rockstro was writing about Britain in 1928. Rockstro (1826-1906) published his Treatise in 1890 and the 1928 version is a posthumous second edition! Ooops!
Even if Rockstro was statistically correct in his quoted comment (highly doubtful), he was writing about the 4th quarter of the C19th at latest.
Kingston's article goes on with some interesting stuff about carbon fibre composites, though - seems it is formed around a mandrel, doesn't have to be turned and reamed, at least, not the bore. You'd "only" have to machine a set of mandrels with the required profiles for the joint bores (for each different flute design you want to produce....)!
I agree with David that Ebonite finishes more attractively than Delrin, and it is available in suitable rod stock, so let's buy some of our makers gas masks, air fresheners and good extraction fans and get 'em working in Ebonite!
EDIT: I was writing this while Jim's last post came on - seems I've covered some of the points he raised. And I'll say again, Ebonite is still quite regularly used for student level clarinets and oboes - and some Boehm system piccolos, I've just coincidentally noticed.
