What is Ebonite?



Hint: It’s not plastic!

Shop Notes Blog

Ebonite is a natural hard rubber and its name comes from the fact that it was invented as a substitute for Ebony the African hardwood. The potential of this food-safe material was discovered by flute makers not long after it was patented in the 1800s (and it should be noted that early ebonite recipes were probably *not *food safe). It is often used for saxophone and clarinet mouthpieces and because it is durable and not affected by moisture it has many advantages for woodwind instruments and has tone reminiscent of dense rosewoods.

It is significantly more costly than wood as a material. The beautifully colored types of ebonite costs about five times as much as African blackwood, a highly favored tonewood.

Richard Rockstro (1826-1906, the famous pupil of Richard Carte) endorsed the material in the following comments:

  1. Firstly, then in the matter of endurance it may be pronounced perfect for it is practicably indestructible.


  2. Secondly, as it is absolutely non-absorbent of moisture no change in the dimensions of the tube ever occurs, and a metal head-ling is unnecessary.


  3. Thirdly, an ebonite flute invariably improves by judicious use.


  4. Fourthly, this substance possesses just the amount of rigidity necessary for the retention of the enclosed air-column in its proper shape and dimensions, while its own vibrations sympathize so readily with those of the air within, that the sound is produced with as little expenditure of the breath as on a metal flute.

  5. 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.


  6. 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.


Ebonite is a pleasure to use. It is beautiful, stable and sounds amazing. Is it a better choice than wood? I would say that sometimes it is, though I would differ with Rockstro in describing it as “practically indestructible”. Ebonite is pretty robust, but if dropped on a hard surface or subjected to trauma it can certainly chip or break, so it is much like wood in that respect. The following quote is from an excellent article written by clarinet maker Tom Ridenour (The Grenadilla Myth). He refers to ebonite as “hard rubber”, which is perfectly accurate. Natural hard rubber is what it is, and the term “ebonite” is more like a brand name that has become a convenient way to refer to it.

“Hard Rubber vs Grenadilla

In my own clarinet design experience I have had the rare opportunity to design clarinets in Grenadilla wood, Rosewood and Hard Rubber. It has been an eye opening, almost shocking experience. What I have found to be consistently true is when a well-made hard rubber clarinet is compared to a Grenadilla wood clarinet sharing the same acoustical design, the hard rubber turns out to be the unequivocal better in every respect: tone, tuning, response, sweeter high tones, stability and consistency in manufacture.

Hard Rubber is Natural

The fact is, too many people operate on the unexamined assumption that hard rubber us just like plastic. But the truth is that hard rubber is not at all like the plastics used for clarinet building. It is not accurate to equate high grade, natural hard rubber clarinets with synthetic, plastic clarinets.

Why?

For one thing, hard rubber is not synthetic at all, but just as natural as any piece of wood in any forest. Hard rubber comes from the very essence of the tree, being its’ life blood. Besides being natural, it is superior to plastics in every possible respect. Musically speaking, pure, natural hard rubber clarinets possess many critical playing and tonal qualities that are almost identical to those of Honduran Rosewood; more so than any other material presently used for clarinet making, including Grenadilla wood!

Comparing Grenadilla and hard rubber clarinets from a pragmatic, logistical standpoint, hard rubber clarinets are consistently more stable, more uniform from clarinet to clarinet, take and hold much more precise and uniform bore dimensions, and are virtually crack-free. On the acoustical/aesthetic/performance side, well-made, well-designed, high quality hard rubber clarinets have quicker response, more even blowing resistance, better, more stable tuning, a darker, sweeter tone and are coloristically much more stable throughout the full pitch and dynamic range of the clarinet. In short, hard rubber clarinets give you the best of both worlds, satisfying the logistical needs of the manufacturer and the artistic needs of the clarinetist.”

This was the article that inspired me to try ebonite in the first place, and my experiences so far coincide exactly with the observations made by Mr. Ridenour. Ebonite is an amazing material for woodwinds.

UPDATE: In an earlier version of this blog post I made the following statement: “Ebonite is an all natural blend of rubber sap, linseed oil and sulfur and is a very sustainable alternative to wood.” I have since learned more about the sourcing of natural rubber sap, and I cannot honestly say that this is true. I don’t think it is any more sustainable than using tropical woods, simply because rubber production itself can have a strong impact in terms of deforestation. Ebonite is made from natural ingredients, so in a world where plastics are such a major problem it has the advantage of not being a polymer. All of it’s other virtues are intact, but I had been conceiving of it as a more “eco-friendly” material than it actually is. Can ebonite be made in an eco-friendly way? Quite possibly, and I think a lot of that comes down to how rubber is sourced and managed, but I have yet to find any information that leads me to think that such practices are being used.

As an instrument maker it is nearly impossible to operate using all-natural materials that are responsibly sourced. Even natural oils like linseed or tung oil are not sustainably produced, though many artisans choose them as a “natural” option for flute making. My current goal is to evaluate all of my materials on an ongoing basis and attempt to gradually reduce my eco-footprints to the degree that I realistically can. It’s a work in progress and some compromises are unavoidable. On the plus side, I only drive about 500 miles per year!



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Published Monday, August 6, 2018