Bone fills

Gali Beiner <galibeiner [at] hotmail__com> writes

>I am working with some very large archaeological bones (elephants,
>hippotami etc.) and part of the collection here features fills for
>bone, made out of a combination of wax with pine resin and gypsum.
>Does anyone know about other instances of fills made out of a
>mixture of these specific materials, and the way they aged with
>time? ...
> ...
>I am asking these questions also because there are problems with
>using materials such as B72 with glass microballoons for very large
>bones: this may not be strong enough and is also very expensive, a
>problem in a very large, but not very budgeted, collection. If
>anyone would like to inform about tested materials in bone fills,
>this would be very helpful.

We're currently conserving an 85 feet long blue whale skeleton
acquired, defleshed and articulated in 1908, which has been
displayed outdoors under shelter for most of its museum life.  It
will be re-articulated using non-invasive, inert materials and
installed indoors in our new atrium.

Part of the treatment involves filling previous mount holes of
various shapes and dimensions.  Small shallow holes are filled with
B72 and glass microballoons, as referred to above.  Long holes which
pierce through vertebrae, ribs, etc. (up to 1 foot long x 1.5  x 3
inches) are filled with a core of Ethafoam B72ed in place, and
surface coated with no more than 1/2 inch of B72 and microballoons.
Large surface gashes (up to 17"L x 4"W x 2"D) have been filled with
a core of denser Ethafoam (twice the normal density), and coated as
above with 1/2 inch B72 and microballoons.  We expect to be able to
recreate missing epiphyses (18 inch diameter x 2 inches thick) and
various extremities which will be pinned in place.  All surfaces are
inpainted with dry pigments in B72 in acetone.

Initially we intended to turn to an epoxy system for the larger
surface areas, not expecting B72 and microballoons to be strong
enough over a wide expanse.  However, in addition to being inert,
reversible, light weight, relatively economical, and easy to apply
and visually blend with the surrounding surface (while easily
distinguishable under UV light), these larger fills have proven to
be firm but not rigid, very securely attached and additionally
distinguishable by their hollow sound when tapped.

Sasha Stollman
Conservator
Canterbury Museum
Rolleston Avenue
Christchurch 8001
New Zealand
+64 3 366 5000
+64 3 366 9429 ext: 845 (direct)
Fax: +64 3 366 5622


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                  Conservation DistList Instance 17:17
                  Distributed: Thursday, July 31, 2003
                       Message Id: cdl-17-17-006
                                  ***