Radiative clock and watch dials

Jim Moss asks for advice on conservation of radioactive clock and
watch dials. Unfortunately these objects are so active that they are
a danger to himself, his colleagues and the public, and I have no
doubt that the advice of the radiation protection authorities will
be to dispose of them forthwith.  (In Britain, and probably in the
USA also, special precautions are needed if the instantaneous dose
rate is greater than 0.25 millirems per hour, and these objects are
up to 1000 times more active!)

It sounds attractive to try to remove the radioactive paint, but
this would be a very hazardous process.  You might be able to get
away with removing just the dials and hands and retaining the works,
if they are not contaminated, but I suspect that this may not be
possible.

I reported on a similar experience with an object which unexpectedly
turned out to be radioactive in a previous instance of the list, and
I repeat my warning to beware of objects that you think might be
radioactive (eg luminous instruments) and get them checked out.

Barry Knight
English Heritage
London

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                 Conservation DistList Instance 10:102
                   Distributed: Monday, May 19, 1997
                       Message Id: cdl-10-102-001
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