Amalgam mirror

Craig Deller <craig1708<-a t->aol< . >com>

>I am looking for information regarding the proper treatment of an
>18th century English mirror, in a frame (6 feet X 2 feet), that
>appears to be sweating mercury. I am well aware of the inherent
>dangers of dealing with the mercury, but has anyone successfully
>consolidated the amalgam?

I haven't got the answer but wanted to share some related
information. In the late 1970's AIC Fellow Sidney Williston was
seeking consolidants for mercury mirror backs and set up some test
panels using many of the synthetic resins in vogue at that time.  He
would have the results of course, but when I last saw the test
panels, most of the coatings had either lost adhesion or had damaged
the metal layer, increasing the gaps between islands of amalgam,
enlarging the alligator patterns already present.

A few years later I had occasion to discuss the problem with Robert
Organ, then head of CAL at the Smithsonian.  He had an idea that
seemed elegant in theory, which involved lining the back of an aging
mirror with pure silver foil to absorb the mercury which is coming
out of solid suspension.  The practical application wasn't tested
but seemed limited.

My own treatments of this problem involve hazard-conscious removal
of liquid mercury, localized cleaning of the reverse glass that has
been exposed by loss, and reframing with the provision of a smooth,
reflective Mylar sheet behind the mirror to create a removable kind
of visual compensation for gross loss.

Hope that's useful.  I'd be interested in other responses and
approaches.

Kory Berrett
Berrett Conservation Studio

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                  Conservation DistList Instance 10:92
                 Distributed: Thursday, April 24, 1997
                       Message Id: cdl-10-92-002
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