Waterlogged ivory

Eva Christensson <eva.christensson [at] rashm__se> writes

>I'm about to conserve a beautifully carved waterlogged ivory
>plaque, probably carved from a walrus tusk, dating to about 1100
>A.D.
>...
>The main problem now is how to dry the plaque from its waterlogged
>state without any warping, cracking and flaking.

Damp or waterlogged bone has responded well to consolidation with
acrylic colloidal dispersions. We have used Primal-WS24 on damp
archaeological material and have found it useful. It requires
repeated applications, followed by a period of drying. Each
application becomes insoluble in water once dry, so immersing the
object again in fresh solution does not dissolve the previous
application. The solutions we used in 1988 are still clear,
colourless and apparently unchanged and Primal has shown well in
other ageing tests.

See:

    Koob, S. The Consolidation of Archaeological Bone in Adhesives
    and Consolidants, IIC Paris Congress 1984, p 98-102

A few years ago we had to treat several ivories which had been badly
damaged by salts and which were warping and splitting in humid
conditions. Removal of the salts was required, although the ivory
was not damp or waterlogged.  We bound the ivory with gauze bandage
before immersing it in consolidant, in this case a solution of
Paraloid B72 in acetone. The ivory was allowed to dry, still in the
bandage. It was then immersed in distilled water (many changes) to
remove the salts. When the conductivity readings had stabilised at a
sufficiently low level, the ivory was removed and allowed to dry.
When dry the bandage was removed. It stuck to the ivory in a few
small places, which were freed with swabs of acetone. The ivories
had remained stable since. Hope this helps,

Helena
R & H Jaeschke, Archaeological Conservators

                                  ***
                  Conservation DistList Instance 12:9
                  Distributed: Thursday, July 9, 1998
                        Message Id: cdl-12-9-001
                                  ***