Water damage to furniture

Jillian Adams <jillianadams [at] ci__lowell__ma__us> writes

>Our museum uses some of its museum space as function space.
>Unfortunately, we've had a recent accident with one of our quality
>pieces. A guest left a sweating glass on our side buffet. Does
>anyone know of ways to work magic (short of incantations) to remove
>the white "stain"? (I do realize that it isn't a stain, but moisture
>trapped under the finish.) Our inventory lists this piece in the
>following manner: "Carved mahogany and veneer Empire Sideboard with
>rope-twisted front, candle stands on ends. The rectangular top, 71
>1/2 by 24 inches, (brasses replaced). American, c. 1840".

When people call up in our workshop with questions like yours
(mostly "Golden Pages" callers) I reply I can't say anything
specific without further examination of the piece.

The problem you are dealing with is not moisture "trapped" under the
finish. The liquid under the glass has got the chance, probably
helped by some alcohol, to penetrate through the finish coating. The
wood fibers have absorbed the liquid and are swollen. After
evaporation of the liquid the fibers have shrunk, but not completely
to the original position. This movement of the wood has destroyed
the connection with the surface layer and turned the spot in an
opaque, greyish circle. Considering the age of the piece and
assuming that we are dealing with an original surface coating I
expect a thin wax or wax-resin surface layer. My suggestion for
treatment would be to tip in the opaque circle with a thin solution
(< 5%) of a resin like shellac or Paraloid. After drying, buff with
a Scotch-pad 0000 and some furniture wax to push back the fibers in
their most original position without sanding. But the case can also
be that the surface-coating is something completely different. Or
the spot has bleached due to the pH of the wood and the liquid. Or
the tannin in the mahogany has caused an oxidation that shows tiny
black spots in the circle.

So please contact a skilled furniture-conservator before acting.

Bart Greebe
Bruys Meubel- en interieurrestauratie
Amsterdam


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                  Conservation DistList Instance 16:39
                Distributed: Tuesday, December 10, 2002
                       Message Id: cdl-16-39-009
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