Bloom on lead

Maria Saffiotti Dale <msaffiottidale [at] lvm__wisc__edu> writes

>I am seeking information on the recommended treatment, routine
>maintenance, and optimal display of a lead sculpture (Raymond
>Duchamp-Villon, "Le Cheval", 1914, cast 1950s; ex-Morton Neumann
>Family collection) which regularly "blooms." We have been
>maintaining it in-house by gently reducing the white oxide layer
>with very fine #0000 synthetic pads followed by the application of a
>coat of Renaissance wax.

Do you have any photographs of the sculpture in question showing the
problem?

My first thoughts are that the pieces should not be cased,
particularly if constructed in the materials you describe.

Internally displayed lead sculpture should not need maintaining
other than dusting, nor in normal circumstances need wax coatings to
protect it, although Renaissance wax should not harm the pieces.
However in a closed environment  porous coatings such as wax may be
entrapping moisture and or pollutants which may be causing the
bloom, is the bloom lead oxide?

My gut feeling is that the sculptures should be taken out of there
cases and displayed open, once lead forms its natural patina its
should act like its own paint, that is the conversion process slows
down to almost a standstill given a reasonably controlled
environment such as indoors. Abrasive cleaning however light should
be avoided if at all possible as this breaks down or removes the
naturally forming protective patina.

If you can provide more information and some photographs then I
should be able to, assist you more.

Rupert Harris
Advisor on Metalwork Conservation to the National Trust.
Consultant to English Heritage on Architectural Metals.


                                  ***
                  Conservation DistList Instance 18:44
                 Distributed: Wednesday, March 16, 2005
                       Message Id: cdl-18-44-010
                                  ***