Eucalyptus oil

Peter N. Krantz <bkfndrs [at] ozemail__com__au> writes

>In conservation and archival use, does eucalyptus oil demonstrate
>any undesirable properties?

Eucalyptus oil is an essential oil. It polymerises with age
(exposure to light?) and/or exposure to air. Old eucalyptus oil
(yellowed) can leave a visible oily stain. This is probably why
there are so many reports in conservation literature of it leaving
such stains. While fresh distilled eucalyptus leaves no visible
stain, there is a prolonged odour, and that area resists wetting. It
stands to reason that there will be some residue.  Eucalyptus oil
will mix with rapid evaporating petroleum based solvents to help
remove such residue, but I am sure you can never be totally sure of
removing all of it. It is quite a good solvent for soft adhesive
tape stains.

Gum turpentine is a similar polymerising product. Violin makers can
get a polymerising exothermic reaction from it by heating, yielding
a thick brown varnish.

James Elwing
Archives Conservator
Powerhouse Museum, Sydney


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                  Conservation DistList Instance 16:7
                   Distributed: Friday, July 19, 2002
                        Message Id: cdl-16-7-005
                                  ***