Re the question on the use of drywall mud vs. plaster as a new "matrix"
for a fossil exhibit:
I could not agree more that plaster mounts for fossils are a pain. This
method originated with many 19th-century British mounts of marine
vertebrates and is a horror to deal with in later years when the specimen
needs conservation or further research. Plaster is also both heavy and
brittle, the worst of both worlds.
However, I would not unreservedly recommend drywall mud or any other such
substance without doing some homework. At Nebraska. the very best
resource is Greg Brown, who is a council member of the Society for the
Preservation of Natural History Collections as well as a trained
preparator who is very familiar with fossil conservation. You should be
able to work with him to get the information on the long-term aging
characteristics of whatever substance you do wind up using. Remember
that your exhibit is not necessarily the last best use of the fossil, and
that someone may have good reason to want to use it for something
altogether different in the future. Be cautious, talk to experts first,
and don't do anything you can't undo when you need to. And, please, find
out everything you can about the substance before you use it. All of us
who spend our career years cleaning up the results of poorly chosen
substance will thank you.
Conservation of geology collections is a concept far less well developed
in this country than is conservation of art and archeology material. I
will be posting a course announcement shortly dealing with just this topic.
There are people who are knowledgeable, and you are lucky to have one in
Lincoln.
 
Sally Shelton
Director, Collections Care and Conservation
(Graduate, Geological Conservation Diploma Course, Cambridge)
San Diego Natural History Museum