Dow Liquid Silicone is used extensively for this, but it is rather
expensive... a hundred plus dollars a gallon.   It's properties do not lend
to the same as does Baby or mineral oil.
The idea of the preservation is wrought in sealing in the moisture.  Once it
is sealed in it will not lend to cracking.  However it the shells are
already old... there may be a need to find a way to moisturize it again.
I've not studied that facet.

Leslie Allen Crnkovic
10440 Valley Forge Drive, #2
Houston, Texas 77042-1918 USA
713-784-7084 / 713-784-9084 Fx / 713-598-7084  Cel


-----Original Message-----
From: [log in to unmask]
[mailto:[log in to unmask]]On Behalf Of Charles Sturm
Sent: 06 December, 2000 9:11 AM
To: Patrick Baker
Cc: [log in to unmask]
Subject: Re: mollusca preserving bivalve shells


Dear Patrick,
  It is my feeling that this problem relates to extreme changes in
humidity.  If the specimens dry too much, they will flex and crack.  This
happened to some of my specimens of Pyganodon, a thin shelled unionid.  My
dehumidifier dropped the humidity from the 50-60% I try to maintain, down
to 38%.  Several of these shells cracked.
  Along with maintaining a stable RH, you can try storing the shells in
polyethylene zip-lock bags.  This will slow down changes in the
microenvironment and help preserve the specimens.
Regards,

Charlie
****************************************************************************
**
Charlie Sturm, Jr
Research Associate - Section of Invertebrate Zoology
                     Carnegie Museum of Natural History, Pittsburgh, PA
Assistant Professor - Family Medicine

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