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Roger

 



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Very interesting.I never knew that.

Roger

 



________________________________
 From: Michael Biel <[log in to unmask]>
To: [log in to unmask] 
Sent: Tuesday, April 24, 2012 4:08 PM
Subject: Re: [ARSCLIST] Diamond Discs Was: Determining substrate of laquer discs
 
From: Roger Kulp <[log in to unmask]>
> Could someone tell me why the surfaces of so many Diamond Discs seem
> to flake and peel off,leaving the core exposed?  Roger

This was a problem in the earlier years because the surfaces were a
celluloid sheet laid on a wood-flour core.  The wood-flour core would
absorb water which is why Edison discs must NEVER be washed. The rims
start to spread and separate, and the celluloid will curl.  The three
dimples in the label area were supposed to help keep the celluloid layer
secure, and they continued to have the dimples in later years when the
top surface was changed to a liquid called Condensite which hardened
with the pressure of the press with pressing times between 20 and 40
minutes.  The core material became changed to clay which did not absorb
water.  This started during the war years when quality materials were
scarce, and the surfaces were not quiet for several years.  It was
finally when they started using the paper labels in the early 20s that
the disc surfaces became quieter.  

Mike Biel  [log in to unmask]