Tuesday, March 4, 2014

Vintage Hard Rubber Mouthpieces - Which Manufacturing Process was the Best?

There were two popular methods for producing vintage hard rubber mouthpieces.  One method used commercially available dowels of vulcanized hard rubber, called rod or bar rubber, and the mouthpiece was machined from the bar stock just as would have been done originally when making a mouthpiece from ebony wood.  The other method was to vulcanize the rubber in a mouthpiece shaped mold and then finish the blank.  Claims have been made over the years that one or the other method produced a superior product.  Let's get the opinion of an expert.
Chedeville mouthpiece Chedeville mouthpiece Chedeville mouthpiece Chedeville mouthpiece
Mr. Otto Link started finishing metal mouthpieces in the mid-1930's.  At first, Goldbeck had a patent on metal pieces and it appears that he used those for his original blanks until the Goldbeck patent expired in 1934.  He began marketing a hard rubber mouthpiece in the late 1930's.  Because of the long-term popularity of his hard rubber line of mouthpieces, he is going to be our expert.  He passed away in the 1970's by most accounts, but we can still use him as our expert based on his informed opinion as stated in his advertising material.  I'll put his statements in quotations and italics.
Link hard rubber link hard rubber link hard rubber link hard rubber link hard rubber
Mr. Link's first hard rubber mouthpiece was intended to "duplicate the Link 4 Star metal mouthpiece."  Metal was expensive, but vulcanized rubber, specifically vulcanized rubber of the same hardness as ebony, could be made into a mouthpiece.  This hard rubber was generically referred to as ebonite and was available in rod form for milling or it could be vulcanized into the shape of the mouthpiece to allow for less milling.
Chedeville hard rubber chedeville hard rubber chedeville hard rubber chedeville hard rubber
Mr. Link chose to use the rod form of hard rubber.  He called the material that he purchased "Eburnated Bar" hard rubber.  If you Google "eburnated bar" you will find thousands of web sites on which that term is used, but they will all refer to Otto Link mouthpieces.  If you Google "eburnated bar -Link" (i.e., without the search term "Link") , you'll get no hits.  So it appears that "eburnated bar" rubber doesn't exist anywhere else on the planet other than in Link mouthpieces.   Very curious. 
Chedeville rod rubber Chedeville rod rubber Chedeville rod rubber Chedeville rod rubber
"Eburnated" is a medical term that generally applies to the body's reaction to a degenerative bone disease.  The cartilage wears away and the bone structure rubs together, resulting in "bony sclerosisor an ivory-like surface referred to as "eburnated."  Ivory-like?  What's that all about?  Wait a minute, we have seen a similar claim.  Remember the ivory mouthpieces in the blog about Sorkin Music that were sold with the Revere Paris Model saxophones?  Are those ivory mouthpieces eburnated?  Sort of.  The Revere saxophones aren't from Paris and the Revere mouthpieces aren't ivory.  That was all just advertising hype.  Just like the term "Eburnated Bar" used by Mr. Link is pure advertising hype.

Here is a vintage Link mouthpiece allegedly made from "Eburnated Bar" rubber. 


Okay, but even if the claim of Eburnated Bar is clearly BS, we now know that  making a mouthpiece from bar stock or rod rubber is best because that's what Mr. Link chose (or at least chose to claim).  The only problem is that within a couple of years Link changed his mind and started using molded blanks.  But somehow the blanks that he purchased were still "eburnated" according to the Link advertising.  Maybe the secret eburnation process is the key to making superior mouthpieces.  Here's some Link advertising copy from 1940.


A new process of high compression actually hardens the rubber from which "OTTO LINK" MOUTHPIECES are fabricated to a degree heretofore thought impossible -- imparting a gleaming crystal quality in appearance as well as substance.  This process minimizes the possibility of warpage oft prevalent in ordinary rubber mouthpieces, and adds a new resonance and brilliance to tonal quality.
It is practically impossible to attain in ordinary cast mouthpieces the high degree of material hardness found in our EBURNATED "RESO-CHAMBER" Otto Link MOUTHPIECE.  Eventually ordinary cast rubber mouthpieces warp from heat and the absorption of moisture from the player's mouth.  This is practically impossible with EBURNATED "RESO-CHAMBER" MOUTHPIECES.
Many reed troubles start with mouthpiece warpage, for when this happens it becomes necessary to find reeds that will fit and play on this warped facing.  Not only will a defect of this nature change your embouchure, but most likely it is apt to set you back considerably in your progress toward mastering your instrument.

Well that explains my lack of progress toward mastering my saxophone.  I often play a 1940's Otto Link Tone Edge, called a "slant signature," that doesn't have the word "eburnated" stamped on it.  So it's just an "ordinary cast mouthpiece."  But it isn't warped.  And it has never gotten water logged.  What's going on here?  The "RESO-TONE" supposedly features a "new process of high compression" casting that differentiates it from other cast mouthpieces.  But just a few years later, Link stopped claiming to use the eburnation process, whatever that was, and just used cast mouthpieces.

Let's look at how vulcanized rubber is cast for a mouthpiece blank.  Hard rubber mouthpiece blanks were "compression molded," but the compression of the material into the mold doesn't change the material property of the rubber.  Cooking the rubber (vulcanization) hardens the material.  Mr. Link's process of "eburnation" supposedly imparted a "gleaming crystal quality in appearance as well as substance."  Every vintage Link mouthpiece that I've ever seen polishes just like any other hard rubber mouthpiece.  And natural rubber already has a crystalline structure, as does vulcanized rubber, so the process of "eburnation" sounds just like the same vulcanization process used for every other hard rubber mouthpiece.  But claiming that Link mouthpieces have a "gleaming crystal quality" sure sounds better than "it's vulcanized."

When rubber is vulcanized, it is cooked under pressure, and the amount of pressure determines the temperature and therefore the cooking time (just as with a stove-top pressure cooker).  Is Mr. Link implying that he orders his blanks cooked at a higher pressure (and therefore, temperature)?  Unfortunately, once rubber is vulcanized, going to a higher temperature doesn't do anything.  So the mystery of eburnation, if it ever existed, remains a secret.  My own opinion is that, if there is no evidence of something's existence despite years of searching, then it doesn't exist.  Call me an eburnation non-believer.  That same lack of evidence is why I don't believe that Mr. Link ever cast his own blanks.  

But a total lack of proof doesn't preclude attributing secret physical benefits to the process.  Mr. Link's secret process "minimizes the possibility of warpage oft present in ordinary mouthpieces".  So the claim is that eburnation doesn't eliminate warpage, it merely "minimizes the possibility."  Where is the proof, i.e., where are the warped Links?  And where are the "oft" warped ordinary mouthpieces?  It actually sounds like those "ordinary mouthpieces" may have dissolved in the player's mouth because of "heat and the absorption of moisture from the player's mouth."  

We know that heat and humidity effects ebonite.  That's what proved the "mouthpiece material matters" claims to be false, remember?  But a "warped" mouthpiece caused by playing?  Why has nobody ever seen one?  It could just be more hype.  In fact, it appears that "eburnation" is synonymous with hype.  It's like Sorkin's claim of "ivory" mouthpieces.*

But back to our quest in determining which is better, vulcanizing the rubber in the shape of a rod or vulcanizing in the shape of a mouthpiece.  One of these methods of shaping must be way, way better in order for us to argue about which finished mouthpiece is obviously superior.  Yet Mr. Link used both methods and advocated for both (depending on which he was employing at the time).  It turns out that, according to him, as long as the material goes through the mystical process of "eburnation," either process can produce a good mouthpiece.  It's too bad that the "eburnation" process for hard rubber wasn't patented (or ever used again by anybody). 

We can also look to another mouthpiece expert, Mr. Charles Chedeville.  Mr. Chedeville was also using rod rubber in the 'teens and 20's prior to the perfection of the molding process.  Some whopping claims are made that he also used a super-duper Grade A++ whing-ding secret formula rod rubber for his mouthpieces.  There is no evidence, of course.  And there is no evidence that Chedeville ever cooked the rod rubber himself or had a proprietary recipe that the manufacturer used only for him.  In fact, if you do a search for his business addresses, just like Otto Link, he was never located at an address where he could have the machinery necessary to vulcanize rubber.  He simply sourced material from a rod rubber manufacturer like Mr. Link sourced his material.  "Please ship 100 sticks of ebonite rod rubber."  Where's the mystical "material matters" evidence in that?

Beginning in the 1920's, Mr. Chedeville used molded blanks (like Mr. Link) and his "golden era" spans his rod rubber and molded mouthpieces.  Since there is also no evidence that he cooked his own molded blanks, it is most likely that he sourced his blanks from Riffault (like many others), which accounts for why many Lelandais and Chedeville pieces are identical to Riffault production pieces.  After all, Riffault was just down the road and sold their clarinet and mouthpiece blanks partially finished.

I know this is heresy, but I'm only going where we have evidence, logic, and common sense while leaving out the hyperbole, fantasy, and delusion.  Of course, that's easy for me to claim that Chedeville probably used Riffault blanks because I don't have any Chedeville mouthpieces for sale and I don't claim to be fabricating present day knock-offs of Chedeville mouthpieces.  Here's how to make a knock-off.

Back to Mr. Link.  There is another interesting "hard rubber" usage by Mr. Link.  In 1930, Mr. Link applied for a patent, along with his then-partner Frank Meyer (later of Meyer Brothers mouthpieces).  The patent was for a tooth guard on a metal mouthpiece.  A slot was cut into the metal mouthpiece and a rubber/sulfur mixture was compressed in to the slot and then vulcanized into place.  You have probably seen this on an old Link or an old Lelandais metal mouthpiece.  So a vulcanized rubber tooth guard was not a particularly novel concept at the time (having been previously used by other manufacturers).  "Prior use" invalidates a patent, but then, not every patent granted is actually valid.  Yet the mere existence of this patent by Mr. Link makes it even more curious that his "eburnation" process for an entire mouthpiece wasn't patented.  And the patent doesn't claim that the tooth guard is "eburnated," despite Mr. Link's familiarity with this allegedly important process that stopped the "warpage" commonly occurring when "ordinary rubber" was used on a mouthpiece.  Very curious.

Even advertising hype can be patented, as a process patent does not have to be valid; the applicant merely needs to assert that the process is novel and hope that the patent issues.  What's even better is to just stamp "REG. U.S. PAT. OFF." on an item and then not even try to apply for a patent.  Just stamping the item without applying for a patent saves time, saves money, and saves the applicant from looking foolish for applying for a patent on an already patented process (like Mr. Link trying to patent Mr. Charles Goodyear's well-known prior patent for the vulcanization of rubber, for instance).  But just stamping "Patented" on an object was later forbidden in 1946 by 35 U.S.C. 292  (right about the time production ended for the allegedly patented "eburnated" Link mouthpieces).  

The statutory "penalty" for violating 35 U.S.C. 292 was a $500 fine to be split between the person bringing suit and the U.S. government.  Few suits were ever brought until an odd court ruling on 2009 and, as a result, the penalty provision was completely eliminated in 2011.   But it is curious that Mr. Link stopped claiming that his "eburnated" mouthpieces were patented right about 1946.  (The elimination of the penalty in 2011 has brought on a renewed use of the bogus "Patent Pend" stamp.)**

Perhaps eburnated vulcanized rubber can't be described in a manner that made a patent application even plausible (applications are sometimes denied).  Or Mr. Link tried to get a patent (which is unlikely as there is no evidence of an application ever being filed), but the patent failed to issue because eburnation is simply a restatement of prior art, i.e., vulcanization.  Or maybe stamping an item with "REG. U.S. PAT. OFF." was commonly used as advertising hype prior to 1946, but Mr. Link decided not to continue the misrepresentation when doing so became illegal.  

At any rate, the issue of whether rod rubber or molded rubber is superior has officially reached a stalemate.   Mr. Link produced great mouthpieces using both methods; with rod rubber (probably produced by American Hard Rubber in Butler, NJ) and with molded blanks (produced by JJ Babbitt in Elkhart, IN).  It's kind of a shame that, like other mouthpiece makers, he catered almost exclusively to a player's obsessive focus disorder for mouthpiece material rather than for mouthpiece design and finish.  Besides having a genius for mouthpiece design and finish, Otto Link also had a genius for creating some extremely powerful marketing hype that continues to this day.  That's the uneburnated truth.

* The silliest claim that I've seen about "ivory" mouthpieces (and I've seen it several times) is that small amounts of ivory dust were added to make these mouthpieces white.  Of course, for those who would believe such a tale it would also change the tone of the mouthpiece (making it sound "mammilion???).  So the common white mouthpieces that the saxophone manufacturer often tossed in the case (and players later tossed out) had expensive ivory dust in them?  All of the players who threw theirs away and bought Links must really be disappointed.  Good thing that Lester Young kept his.

** In the picture of the ResoChamber shown above, you can see the "REG. U.S. PAT. OFF." stamp.  There is no number following the claim, so it isn't clear what alleged patent is referenced.  Link had a patent for a tooth guard on a metal piece, but I can find nothing about Link hard rubber or "eburnated" pieces.  Eugene Bercioux of Woodwind N.Y. stamped his mouthpieces with a U.S. Pat. Off. claim, but his patent was for the machine that put the facings on the mouthpiece and did not concern the mouthpiece itself.  Mr. Bercioux did apply for several trademarks (e.g. "Steel Ebonite"), which trademarks are registered with the U.S. Patent Office.  


Vintage Hard Rubber Mouthpieces - Which Manufacturing Process was the Best?

There were two popular methods for producing vintage hard rubber mouthpieces.  One method used dowels of vulcanized hard rubber, called rod rubber, and the mouthpiece was milled out just as would have been originally done when making a mouthpiece from ebony wood.  The other method was to vulcanize the rubber in a mouthpiece shaped mold and then finish the blank.  Claims have been made over the years that one or the other method produced a superior product.  Let's get the opinion of an expert.
Chedeville mouthpiece Chedeville mouthpiece Chedeville mouthpiece Chedeville mouthpiece
Mr. Otto Link started producing metal mouthpieces in the 1930's (some say earlier, however, there is no evidence).  He began marketing hard rubber mouthpieces in the late 1930's.  Because of the popularity of his hard rubber line of mouthpieces, he is going to be our expert.  He passed away in the 1970's by most accounts, but we can still use him as our expert based on his informed opinion as stated in advertising material.  I'll put his advertising statements in quotations and italics.
Link hard rubber link hard rubber link hard rubber link hard rubber link hard rubber
Mr. Link's first hard rubber mouthpiece was intended to "duplicate the Link 4 Star metal mouthpiece."  Metal was expensive, but vulcanized rubber, specifically vulcanized rubber of the same hardness as ebony, could be made into a mouthpiece.  This hard rubber was generically referred to as ebonite and was available in rod form for milling or it could be vulcanized into the shape of the mouthpiece to allow for less milling.
Chedeville hard rubber chedeville hard rubber chedeville hard rubber chedeville hard rubber
Mr. Link chose to use the rod form of hard rubber.  He called the material he purchased "Eburnated Bar" hard rubber.  If you Google "eburnated bar" you will find thousands of web sites on which that term is used, but they will all refer to Otto Link mouthpieces.  If you Google "eburnated bar" without the search term "Link" (by typing "-Link"), you'll get no hits.  So it appears that the material "eburnated bar" rubber doesn't exist anywhere else on the planet other than in Link mouthpieces.   Very curious. 
Chedeville rod rubber Chedeville rod rubber Chedeville rod rubber Chedeville rod rubber
"Eburnated" is a medical term that generally applies to the body's reaction to a degenerative bone disease.  The cartilage wears away and the bone structure rubs together, resulting in "bony sclerosisor an ivory-like surface referred to as "eburnated."  Ivory-like?  What's that all about?  Wait a minute, we have seen a similar claim.  Remember the ivory mouthpieces in the blog about Sorkin Music that were sold with the Revere Paris Model saxophones?  Are those ivory mouthpieces eburnated?  Sort of.  The Revere saxophones aren't from Paris and the Revere mouthpieces aren't ivory.  That was all just advertising hype.  Just like the term "Eburnated Bar" used by Mr. Link is pure advertising hype.

Here is a vintage Link mouthpiece made from "Eburnated Bar" rubber. 


Okay, but even if the claim of Eburnated Bar is clearly BS, we now know that  making a mouthpiece from bar stock or rod rubber is best because that's what Mr. Link chose to make fine mouthpieces.  The only problem is that within a couple of years Link changed and began using molded blanks.  But somehow the blanks that he purchased were still "eburnated" according to the vintage Link advertising.  Maybe this secret eburnation process is the key to making superior mouthpieces?  Here's some Link advertising copy from 1940.


A new process of high compression actually hardens the rubber from which "OTTO LINK" MOUTHPIECES are fabricated to a degree heretofore thought impossible -- imparting a gleaming crystal quality in appearance as well as substance.  This process minimizes the possibility of warpage oft prevalent in ordinary rubber mouthpieces, and adds a new resonance and brilliance to tonal quality.
It is practically impossible to attain in ordinary cast mouthpieces the high degree of material hardness found in our EBURNATED "RESO-CHAMBER" Otto Link MOUTHPIECE.  Eventually ordinary cast rubber mouthpieces warp from heat and the absorption of moisture from the player's mouth.  This is practically impossible with EBURNATED "RESO-CHAMBER" MOUTHPIECES.
Many reed troubles start with mouthpiece warpage, for when this happens it becomes necessary to find reeds that will fit and play on this warped facing.  Not only will a defect of this nature change your embouchure, but most likely it is apt to set you back considerably in your progress toward mastering your instrument.

Well that explains my lack of progress toward mastering my saxophone.  I often play a 1940's Otto Link Tone Edge, called a "slant signature," that doesn't have the word "eburnated" stamped on it.  So it's just an "ordinary cast mouthpiece."  It also isn't warped.  And it has never gotten water logged.  What's going on here?  The "RESO-TONE" supposedly features a "new process of high compression" casting that differentiates it from other cast mouthpieces.  But just a few years later, Link discontinued using the eburnation process, whatever that was, and used cast mouthpieces.

Let's look at how vulcanized rubber is cast for a mouthpiece blank.  Hard rubber mouthpiece blanks were "compression molded," but the compression of the material into the mold doesn't change the material property of the rubber.  Cooking the rubber (vulcanization) hardens the material.  Mr. Link's process of "eburnation" supposedly imparted a "gleaming crystal quality in appearance as well as substance."  Every vintage Link mouthpiece that I've ever seen polishes just like any other hard rubber mouthpiece.  And natural rubber already has a crystalline structure, as does vulcanized rubber, so the process of "eburnation" sounds just like the same vulcanization process used for every other hard rubber mouthpiece.  But claiming that Link mouthpieces have a "gleaming crystal quality" sure sounds better than "it's vulcanized."

When rubber is vulcanized, it is cooked under pressure, and the amount of pressure determines the cooking time (just as with a stove-top pressure cooker).  Is Mr. Link implying that he orders his blanks cooked at a higher pressure (and therefore, temperature)?  Unfortunately, once rubber is vulcanized, going to a higher temperature doesn't do anything.  So the mystery of eburnation, if it ever existed, remains a secret.  My own opinion is that, if there is no evidence of something's existence despite years of searching, then it doesn't exist.  Call me an eburnation non-believer.  That same lack of evidence is why I don't believe that Mr. Link ever cast his own blanks.  

But a total lack of proof doesn't preclude attributing secret physical benefits to the process.  Mr. Link's secret process "minimizes the possibility of warpage oft present in ordinary mouthpieces".  So eburnation doesn't eliminate warpage, it merely "minimizes the possibility."  Where is the proof, i.e., where are the warped Links?  And where are the "oft" warped ordinary mouthpieces?  It actually sounds like those "ordinary mouthpieces" may have dissolved in the player's mouth.  Maybe that's why nobody has ever seen one?  Or, it could be more hype.  In fact, it appears that "eburnation" is synonymous with hype.  It's like Sorkin's claim of "ivory" mouthpieces.*

But back to our quest in determining which is better, vulcanizing the rubber in the shape of a rod or vulcanizing in the shape of a mouthpiece.  One of these methods of shaping must be way, way better in order for us to argue about which finished mouthpiece is obviously superior.  Yet Mr. Link used both methods and advocated for both (depending on which he was employing at the time).  It turns out that, according to him, as long as the material goes through the mystical process of "eburnation," either process can produce a good mouthpiece.  It's too bad that the "eburnation" process for hard rubber wasn't patented (or ever used again by anybody). 

We can also look to another mouthpiece expert, Mr. Charles Chedeville.  Mr. Chedeville ran a small shop in France that produced woodwind reeds, woodwind pads, and woodwind mouthpieces.  The reeds and pads have all rotted away and disappeared, but the mouthpieces, being primarily made of ebonite, have survived.  Today, Mr. Chedeville is known exclusively for mouthpieces, which was not true when he had his business on Rue Leblanc in the town of La Couture-Boussey.  The finishing of woodwind mouthpieces was only one aspect of his shop.

Chedeville may have used rod rubber in the 1920's prior to the perfection of the molding process (nobody really knows).  Some whopping claims are made that he also used a super-duper Grade A++ whing-ding secret formula rod rubber for his mouthpieces.  There is no evidence, of course.  And there is no evidence that Chedeville ever cooked (vulcanized) the rod rubber himself or had a proprietary recipe.  In fact, if you do a search for his business addresses you will find that, just like Otto Link, he was never located at an address where he could have the machinery necessary to vulcanize rubber.  His business was always a tiny store front (unlike the nearby factory setting of Riffault et Fils where he likely purchased his mouthpiece blanks). And if you Google "Grade A rod rubber," you will see that, like Link's "eburnated bar rubber," there is only a single mouthpiece business claiming that such a material even exists.  Chedeville simply sourced material from a rod rubber manufacturer like Mr. Link sourced his material.  "Please ship 100 sticks of ebonite rod rubber."  Where's the mystical material in that?


Beginning in the 1920's, Mr. Chedeville used molded blanks (like Mr. Link) and his "golden era" spans his rod rubber and molded mouthpieces.  Since there is also no evidence that he molded and cooked his own blanks, it is most likely that he sourced his blanks from Riffault (like many others), which accounts for why many Lelandais and Chedeville pieces are identical to Riffault production pieces.  So now, Chedeville is known for mouthpieces, specifically clarinet mouthpieces that look to be based on Riffault blanks.

I know this is heresy, but I'm only going where we have evidence, logic, and common sense while leaving out the hyperbole, fantasy, and delusion.  Of course, that's easy for me because I don't own or have any Chedeville mouthpieces for sale.  If I was selling Chedeville knockoffs, I would claim to have the secret recipe for ebonite that Charles Chedeville developed based on his expertise in the science of "acoustical chemistry."  If you believe that there is a science of acoustical chemistry, then you will likely believe that someone has the secret recipe.

Back to Mr. Link.  There is another interesting "hard rubber" usage by Mr. Link.  In 1930, Mr. Link applied for a patent, along with his then-partner Frank Meyer (later of Meyer Brothers mouthpieces).  The patent was for a tooth guard on a metal mouthpiece.  A slot was machined into the metal mouthpiece and a rubber mixture was compressed into the slot and then vulcanized in place.  You have probably seen this on an old Link or an old Lelandais metal mouthpieces.  So it was not a particularly novel concept at the time (having been previously used by other manufacturers).  "Prior use" invalidates a patent, but then, not every patent granted is actually valid.  Yet the mere existence of an early patent by Mr. Link makes it even more curious that his "eburnation" process for an entire mouthpiece was never patented.  And the "tooth guard" patent application never claimed to be "eburnated" despite Mr. Link's familiarity with this allegedly important process that stopped the "warpage" commonly occurring when "ordinary rubber" was used on a mouthpiece. 

Advertising hype can actually be patented, as a process patent does not have to be valid in order to issue; the applicant merely needs to assert that the process is novel and hope that the patent issues.  What's even easier is to just stamp "REG. U.S. PAT. OFF." on an item and then not bother to to apply for a patent.  That saves time, saves money, and saves the applicant from looking foolish for applying for a patent on an already patented process (like trying to re-patent Mr. Charles Goodyear's well-known prior patent for the vulcanization of rubber, for instance).  

Claiming a patent, or stamping "Pat. Pending" can ward off competition even if not true.  But just stamping "Patented" on an object was later forbidden in 1946 by 35 U.S.C. 292  (right about the time production ended for the allegedly patented "eburnated" Link mouthpieces).  The statutory "penalty" for violating 35 U.S.C. 292 was a $500 fine to be split between the person bringing suit and the U.S. government.  Few suits were ever brought until an odd court ruling on 2009 and, as a result, the penalty provision was completely eliminated in 2011.   But it is curious that Mr. Link stopped claiming that his "eburnated" mouthpieces were patented right about 1946 when false patent claims became illegal.  (In fairness, thousands of "Pat. Pend." designations disappeared at the time).

Perhaps eburnated vulcanized rubber can't be described in a manner that made a patent application even plausible (applications are sometimes denied).  Or perhaps a patent was considered (which is unlikely as there is no evidence of the application ever being filed), but failed to issue because eburnation is simply a restatement of prior art, i.e., vulcanization.  Or maybe stamping an item with "REG. U.S. PAT. OFF." was commonly used as advertising hype prior to 1946, but Mr. Link decided not to continue.  

At any rate, the rod rubber/molded rubber issue is a draw.   Mr. Link produced great mouthpieces using both methods; with rod rubber (probably produced by American Hard Rubber in Butler, NJ) and with molded blanks (produced by JJ Babbitt in Elkhart, IN).  It's kind of a shame that, like other mouthpiece makers, he catered almost exclusively to a player's obsessive focus disorder for mouthpiece material rather than for mouthpiece design and finish.  Most likely, besides having a genius for mouthpiece design and finish, he also had a genius for creating some extremely powerful marketing hype that continues to this day.  That's the uneburnated truth.

* The silliest claim that I've seen about "ivory" mouthpieces (and I've seen it several times) is that small amounts of ivory dust were added to make these mouthpieces white.  Of course, for those who would believe such a tale it would also change the tone of the mouthpiece (making it sound "mammilion???).  So the common white mouthpieces that the saxophone manufacturer often tossed in the case had expensive ivory dust in them?  All of the players who threw theirs away and bought Links must really be disappointed.  Here is a blog on Lester Young's white plastic mouthpiece.