Removing old polish residue

With regard to removing polishing residues for small objects by running
them through an ultrasonic cleaner, proceed with great caution if the
object is plated.  If a plated metal surface does not have perfect
adhesion between the plated layer and the substrate, the energy dose
from the ultrasonic bath can cause the catastrophic delamination.  In my
experience, this delamination starts at the point of delamination and
proceeds by lifting a sinuously winding lines from the beginning
point---a phenomenon called filiform delamination.  As far as I have
been able to determine once this has happened, there is not much to do
about it.  This type of delamination happens very fast in an ultrasonic
cleaning bath and it makes you feel rather helpless.  Since, it is
usually not possible to spot areas of poor adhesion in a plated piece of
metal by simple visual examination, I would not risk putting a plated
object into an ultrasonic bath.

Susan Barger
Department of Earth and Planetary Sciences
University of New Mexico

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                  Conservation DistList Instance 7:70
                  Distributed: Thursday, April 7, 1994
                        Message Id: cdl-7-70-003
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