The word "vulcanite" or "ebonite" is like the word "bread".
How many recipes are there for it? As many as people want to come up with.
Before the Plastic Age, vulcanite was used in all manner of common things, from radios to telephones to writing pens to fishing reels to musical instruments to bowling balls, and every manufacturer of the stuff (undoubtedly) claimed theirs was the best.
As for "grades" today, there is no industry standard upon which to base scores. The guys who work with it just learn what's best for their application from experience.
How many recipes are there for it? As many as people want to come up with.
Before the Plastic Age, vulcanite was used in all manner of common things, from radios to telephones to writing pens to fishing reels to musical instruments to bowling balls, and every manufacturer of the stuff (undoubtedly) claimed theirs was the best.
As for "grades" today, there is no industry standard upon which to base scores. The guys who work with it just learn what's best for their application from experience.