Rusted nails on modern painting

We are currently treating a modern painting on masonite that has
been damaged by water.  The work, dating from the late fifties, is
composed of a synthetic rubber medium--a butadiene-nitrile acrylic
co-polymer--and titanium white (FTIR revealed the presence of other
components not yet identified). The panel is held on a strainer by
nails and glue.  As a result of the water damage, the nails of the
lower edge have started to rust.  The corrosion has created dark
rings around the nails and has caused the surrounding paint to
fracture and flake away.  The nail heads are on the face of the
painting in an area of white paint.

So far, we have mechanically removed all traces of corrosion on and
directly around the nails.  Some corrosion traces are still visible
as a dark brown halo around the nail in the paint layer.  We are now
questioning ourselves on the next appropriate steps to follow.

    1.  Should we remove the nails? If so, replace them with what?
        What are the advantages or disadvantages of such an
        intervention?  Is this step really necessary now that the
        work will be in a museum environment?

    2.  Should we chemically stabilize the nails?  If so, with what?
        What are the chances of interaction with the surrounding
        paint layer ?

    3.  Would sealing the nails be enough to prevent further
        corrosion?  If so, with what?

    4.  What material should be used to fill the losses over and
        around the losses?

Technically, this type of copolymer should be resistant to many
solvents. Unfortunately, we have found that water readily dissolves
some components in the paint. Any input from conservators who have
faced this type of problem or simply from those who have an opinion
on this matter would be welcomed.

Chantal Bernicky
Restauratrice - Atelier des Peintures
Centre de conservation du Quibec


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                  Conservation DistList Instance 16:50
                   Distributed: Monday, March 3, 2003
                       Message Id: cdl-16-50-020
                                  ***