Plaster reliefs

Saye Khajeian <khajeian [at] yahoo__com> writes

>We are working in a mosque that belongs to 300 years ago and there
>is fine decorative art, of gypsum. For some reason its surface is
>covered by oily germs of candle.  Does anyone have any idea that how
>can I treat this? ...

We have done some work on fragments of spanish Islamic plasterwork
(14th century) from the Alhambra Palace in Granada. Regarding the
use of wax for the production of plasterwork I am not aware of wax
being a traditional material and certainly in the alhambra
plasterwork was never used even on the most interventive
restorations from the 19th century.

I understand that the wax you mention is more a candle wax than a
coating applied on purpose.

Amir Hosein Karimy <ahkarimy [at] yahoo__com> writes

> ... If you are
>certain must be removed you can use dimethyl formamide; I think it
>will work.

For the removal of the wax I would certainly avoid the use of
dimethyl formamide as it is a highly toxic and carcinogenic solvent.
I would used instead simple white spirit which works perfectly on
the removal of wax. Certainly you will need to assess the
application procedure in order to allowing avoid the diluted wax to
travel into the plaster. This may have cause the darkening of the
plaster.

Probably a combination of mechanical removal of the thick wax first
an then use the solvent will be most appropriate. I do not think the
white spirit would darken the plaster on its own.

Hope that helps,

P.S. I am very interested on Islamic plasterwork. Maybe you could
let me know the location of the mosque you are working on?

Victor Hugo Lopez Borges
Sculpture Conservator
SMCG Section
Victoria and Albert Museum
London SW7 2RL
+20 7942 2121
Fax: +44 20 7942 2092


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                  Conservation DistList Instance 20:22
                 Distributed: Sunday, October 29, 2006
                       Message Id: cdl-20-22-003
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