[78-L] Pressed in WHAT material...

[John Maeder]

Edison's chemists produced a substance nearly identical to Bakelite (which was developed by Leo Bakeland just a few miles away and practically at the same time) that Edison named 'Condensite'.  Both are phenolic resins derived from coal tar using phenolic acid ('phenol') as a solvent.  The surfaces of Edison's 'Diamond Disc' records were made from this substance and comprised the playing surface. The Condensite was laminated to the record core, the core being composed of a mixture of wood flour (finely ground sawdust), hide glue as a binder, and later, clay, to resist moisture absorbtion.  For a time, a thin layer of rubber was between the core and the surface, but this proved prone to delaminating and use was discontinued. During WWI, Edison's supply of phenol feom Germany's Bayer Pharaceutical was cut off due to Britain's naval blockade, so Edison began manufacturing his own.  Within a short time, his company was supplying phenol to all the allied countries.  However, his phenol was not as refined as Bayer's, consequently Diamond Discs produced during the WWI period have noisier surfaces than earlier and later examples.

The wiki articles are also incorrect in saying that the records were produced by "the Edison Electric Co".  Not true!  They were produced by Thomas A. Edison, Inc. and many were marked "A Product Of The Edison Laboratories" on the label.  Someone needs to edit the wiki articles!

> From: milanpmilovanovic4 at gmail.com
> To: 78-l at 78online.com
> Date: Mon, 16 Nov 2009 15:10:03 +0100
> Subject: [78-L] Pressed in WHAT material...
> 
> Hello list members,
> 
> I came across this article:
> http://en.wikipedia.org/wiki/Shellac
> 
> Also this one:
> http://en.wikipedia.org/wiki/Bakelite
> 
> Both claimed that "some" records were made from bakelite:
> 
> "Until the advent of vinyl around the 1940s, most gramophone records were pressed from shellac compounds (although some were made from bakelite)"
> 
> "Recording cylinders produced by the Edison Electric Company (now General Electric) and 78-rpm phonograph records were originally made of Bakelite. "
> 
> I would like to know if such statements are close to the truth. I always thought that no bakelite was used in phonograph record production.
> 
> 
> Thanks,
> 
> Milan
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