Deterioration of plastic

Suzanne Kitto <suzanne.kitto [at] armouries__org__uk> writes

>We have a number of revolvers in our collection dating from 1950s
>that have deteriorating plastic grips.  According to the
>manufacturers the grips are Bakelite but I have never seen Bakelite
>deteriorate in this manner.  The grips have in places a white bloom
>which in areas has formed small white compact crystals. On some of
>the grips the plastic has laminated and cracked.  All the grips are
>giving out a strong unpleasant odour which can only be described as
>smelling of excrement.  My feeling is that the smell maybe from a
>degrading oil.  I would be grateful for any ideas on what could be
>happening or if any one else has come across anything similar.

Have you tested the white crystals for chlorides? I'm guessing here
that the grips are deteriorating due to a combination of moisture,
organic oils and salt resulting from handling, and fluctuating
humidity levels. If this is found to be the case, then I would
suggest that you clean the grips in a non-aqueous solution(s),
after appropriate testing, of course. Hope this helps,

George Bailey
Objects Conservator
Australian War Memorial


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                  Conservation DistList Instance 15:43
                 Distributed: Monday, December 17, 2001
                       Message Id: cdl-15-43-011
                                  ***