As we use it, it is what's called hard rubber. Its made by mixing a polymer with fillers, processing aids, some functional additives, colorants and a curing agent. The filler for black ebonite is carbon, the filler for colored and swirled ebonite is a type of clay. The main curing agent is sulfur which is what makes it stinky. The hardness is a function of how much filler is used, how little softeners are used and how much it is cured.
Not to be confused with the trademark Ebonite which was and may still be used for bowling balls which at one time were made from a similar mix.
As we use it, it is what's called hard rubber. Its made by mixing a polymer with fillers, processing aids, some functional additives, colorants and a curing agent. The filler for black ebonite is carbon, the filler for colored and swirled ebonite is a type of clay. The main curing agent is sulfur which is what makes it stinky. The hardness is a function of how much filler is used, how little softeners are used and how much it is cured.
Not to be confused with the trademark Ebonite which was and may still be used for bowling balls which at one time were made from a similar mix.
Being serious, this is all very consistent with the info Dawn & I gained in our meetings with the ebonite person, from Germany.
Additional information--the heat and pressure processing process is subject to great difficulty. While they are very proud of their extremely high quality raw materials, the "barrier to entry" that she cited most often was the "curing" process.
But, that was NOT what you asked.
Funny that this post should come up this evening. I was just looking at some trying to decide if I wanted to give it a try on one of my high end kits i just got. Any advise on what a good way to finish it would be? I would like some gloss to it, but don't want to lose the "feel" of the blank. BTW, don't want to hijack this thread, but figure it's all related...