Bleaching danger: was yellow ivories

David Love davidlovepianos@hotmail.com
Tue, 08 May 2001 04:35:08 -0000


After bleaching ivories regularly for many years I have given up the 
practice and do not recommend it.  Recently I had discussions with a veteran 
ivory installer as well as a museum conservator about this very subject.  
Though a 30% peroxide solution will do the job, the danger of compromising 
the glue joint is high because you must keep the ivory wet for too long a 
period of time.  Ivory is very hygroscopic as is the hide glue which is 
traditionally used to glue the ivories down.  Further, because the joint 
between the head and tail is not bound by glue (the glue is actually kept 
away from the joint by about 1/16" during the initial gluing process to keep 
the joint invisible) the water from the peroxide can seep into the joint 
causing tenting, loosening of the ivory from the joint, or uneveness at the 
joint.  If you must, the best way to take the yellow out of old ivories is 
to sand them lightly and buff them to get the type of sheen that you want 
making sure not to let the buffing wheel get them too hot.  In terms of the 
aesthetic; my current attitude is that the ivories are antique works of art. 
  If they are in otherwise good shape, what's a little yellowing.  The 
potential of having them start to pop off in order to get them "whiter than 
white" is simply not worth it.

David Love
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