Fossils

Dominique Rogers <do [at] pepin__demon__co__uk> writes

>I am looking for alternatives; waiting for them I am back to the
>old cellulose nitrate that yellows, and will fail in 100 years or
>animal glues that yellow shrink and will fail in 300 years given an
>adverse environment but they stick and are easy to reverse!

I would like to make a general comment on the use of cellulose
nitrate adhesives in conservation.  It is true that early cellulose
nitrate plastics do break down forming nitric acid.  However a study
at the British Museum of cellulose nitrate adhesive up to 50 years
old and sampled from objects showed that the adhesive has good
stability.  The ageing of the sampled adhesives was compared with
that of both modern pure cellulose nitrate and HMG cellulose nitrate
adhesive, see

    Shashoua, Y., Bradley, S.M., and Daniels, V.D.
    Degradation of cellulose nitrate adhesive
    Studies in Conservation, 37, (1992) 113-119.

Cellulose nitrate adhesives have many good properties.  They are
easy to handle, are easy to reverse, have good retention of
reversibility, and show minimal yellowing after 50 years of natural
ageing.  They are a useful member of the conservators lexicon of
materials.

Susan Bradley
Head of Conservation Research Group
Department of Conservation
British Museum
London WC1B 3DG
+44 20 7323 8679
Fax: +44 20 7323 8636


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                  Conservation DistList Instance 15:34
                 Distributed: Monday, October 22, 2001
                       Message Id: cdl-15-34-006
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