Mercury backing on mirrors

Detlef Klein <klein [at] pncc__govt__nz> writes

>I have a clock case decorated with, amongst other materials, mirrors
>cut as mouldings. The clock is 18th century and French, the mirrors
>are mercury backed and originally adhered to the oak case work with
>animal glue. The mercury has in some cases separated from the glass,
>small droplets gathering in cracks etc of the case. The mirror
>mouldings are insecure or have separated.

I will leave the treatment issues to conservators with clock and
mirror experience.   You can easily deal with the mercury droplets
through use of a commercially available mercury collector. Check
laboratory supply catalogues for these. The one I am familiar with
is made by a company called Bel-Art, distributed by Canlab Division
of Travenol Canada, but I am sure there are other brands and
suppliers. It consists of a screw top polyethylene jar with a
perforated disk fixed inside and a loose sponge. You press the
sponge over the droplets, which traps them, then press the sponge
onto the disk. The mercury ends up in the bottom of the jar, you
close the lid and then the whole thing can be dealt with according
to local waste disposal requirements.

If you have droplets in inaccessible spots, you may have to cut up
the sponge to get at them.

Valery Monahan
Conservator
Heritage Branch, Dept. of Tourism
Government of Yukon
867-667-3431
Fax: 867-667-5377


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                  Conservation DistList Instance 15:28
                 Distributed: Tuesday, October 2, 2001
                       Message Id: cdl-15-28-004
                                  ***