Freezing objects

The National Museum of the American Indian is freezing a large
number of ethnographic objects for preventive pest control as part
of a five-year move project.  Some types of materials, such as wool,
are routinely frozen, while others (tooth for example) are not
frozen due to the risk of damage.  A wool dress with elk tooth
decoration would be a candidate for freezing because wool is
attractive to the pests known to be present in the old storage
facility, but we would hesitate to freeze an object with elk teeth
for fear the teeth might crack.

The move project is facing many such scenarios, and has begun to
investigate the issue more closely, with the intention of sharing
the results with the rest of the museum community.  Could those of
you who have seen damage caused by freezing for pest control please
share your observations? The damage we are concerned about includes
cracking, crack propagation, delamination, fatty bloom, spew (spue
for some of us), loss of adhesion, exacerbation of bead disease and
so forth.

As Gali Beiner recently mentioned, there is little in the literature
regarding damage to artifact materials from freezing.  I would be
delighted to talk with others interested in addressing that gap.

Ellen Roblee
Mellon Fellow in Conservation
National Museum of the American Indian
301-238-6624 x 6288


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                  Conservation DistList Instance 14:51
                  Distributed: Tuesday, April 3, 2001
                       Message Id: cdl-14-51-019
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