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Subject: Consolidating bone

Consolidating bone

From: Emily M. O'Brien <emily<-a>
Date: Friday, February 29, 2008
I'm working for an archaeological project in Yucatan, Mexico, and I
am writing a proposal to treat a shell mosaic-covered human skull.
The bone is extremely degraded and broken into 250 pieces.  I was
proposing to consolidate the bone with dilute Paraloid B-72 prior to
reconstruction, but when I consulted with a Mexican conservator, she
said that the Mexican government would probably not approve the use
of B-72 for consolidation. She says that they don't like using
synthetic materials to consolidate, and she said that with the heat
and humidity (no climate control in storage here), they have had
problems with synthetic adhesives and consolidants degrading,
yellowing, and becoming brittle.  Hasn't B-72 held up well over
time?  Are they just conflating it with cellulose nitrate adhesives?
I know that the Tg of B-72 can cause problems with slumping, but
that isn't really an issue with consolidation.

She says that they use lime water (calcium hydroxide) to consolidate
stucco and shell, and she was suggesting that I use it on the bone.
Is this an acceptable and effective treatment for bone?

She also suggested I try a consolidation treatment for degraded
archaeological bone and shell that they have recently developed here
in Mexico.  I only have a vague description, because the conservator
who has developed it has not published on it yet.  It's roughly a
mix of Sodium Fluoride or Calcium Fluoride with chitin or chitosan,
processed somehow with acetic acid.  I've sent an email to the
conservator regarding her product, but haven't received a response.
Has anyone heard of a similar product?  I would love to get more
information and opinions on this.

It seems like conservators down here are interested in using natural
and/or indigenous materials in conservation treatments as much as
possible, as opposed to easily distinguishable synthetic materials
that US conservators generally prefer.  They say that this bone and
shell consolidant is great because it is effective and doesn't
hinder future analysis.

Emily M. O'Brien
Objects conservator
Proyecto Arqueologico Xuenkal
Merida, Mexico

                  Conservation DistList Instance 21:46
                  Distributed: Thursday, March 6, 2008
                       Message Id: cdl-21-46-025
Received on Friday, 29 February, 2008

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