Coating on iron

The object in question is a leather bound book of 80 very thin
rolled iron sheets, made in the 1860's to advertise the skill of a
tin-plate making company in South Wales. Each sheet has been
lacquered with a clear-brownish material, which has now in many
places degraded, having 'melted', migrating into thicker, still
slightly sticky brown patches. The iron seems to be rusting through
breaches in the lacquer. FTIR analysis will be done soon, but
research into the history so far suggests that the lacquer is most
probably a boiled linseed oil; solvent tests have been done, and the
varnish blobs dissolve easily in IMS (shellac?), but also relatively
easily in white spirit and acetone (but not water).

So, I would be very interested to know if anyone has seen anything
similar, knows more about what the lacquer might be or more about
the uses of linseed oil for such purposes, knows more about if the
lacquer or its degradation products are directly damaging to the
iron, or could point me in the direction of any literature that
might help.

Felicity Woor


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                  Conservation DistList Instance 16:69
                   Distributed: Tuesday, May 6, 2003
                       Message Id: cdl-16-69-011
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