David,

Here are a few off the top of my head.

Vacuam packing means encapsulating an object (usually food) between two
plastic sheets and evacuating the air  until it pulls tight over the form -
then the plastic is heat sealed.

First concern would be whether the fragile bone could sustain the pressure
when the plastic pulls tight over the artifact - and the pressure on it
would be long-term. I would also worry about potential modification of the
surface topology and information by such close and tight contact with
plastic.

Second concern is the quality of the plastic - if it outgasses or had
residual acids or decomposition products that could interact with the
inherent moisture in the bone - then it is in very intimate contact with the
bone surface with a large reaction surface.

Third concern is accessibility - an encapsulated bone would not be very
accessible for close examination / measurement / sampling. And to remove it
would involve physically cutting away the plastic till you break into the
cavity around the artifact - the bone could well be damaged from attempts to
remove it.

As in all things dealing with preservation / conservation I would suggest
running some controlled tests before subjecting a whole collection to this
technique.

Cheers!
Dave

David Harvey
Senior Conservator
Los Angeles, CA

On Mon, Aug 10, 2009 at 2:05 PM, David K. Wade <[log in to unmask]> wrote:

> Hello All!   I could use your assistance here....As an archaeology
> repository, we
> often receive recovered animal bone as part of an accession, in vast
> quantities.
> Often, these specimens are articulated and fragile.  We are visiting with
> the idea
>  of vacuum packing some of these items and are coming up with a long list
> of
> 'pros', but very few 'cons'.  Can anyone offer up some insight to us what
> we may
> be overlooking?  It would be most appreciated!
>
> Thanks.
>
> David K. Wade
> Billings Curation Center
> Billings, Montana
>
> www.mt.blm.gov/bcc
>
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