Hadrosaur Egg / Nest Display / Diorama

[Arch2000]

I recently purchased 2 Hadrosaur eggs, they were once joined but the matrix joining them has split (they can still be positioned as they were together, just with a visible crack where the split is). As they are heavy, fragile, and already split I want to display them and keep them safe, here's what I'm thinking:

I have a plexiglas tray (thick) that they fit in nicely. I want to create a ground-cover like base that they can sit in, which will have some indentations to keep them from moving, and wanted to make this look like sand or riverbank mud as they would be found in their original natural state. Essentially making a nest or backdrop of their natural surroundings. Then I would place a plex cover to keep dust out.

Rather than just fill the tray with sand (which would be messy, likely not too accurate, and wouldn't keep them in place), I want to pour in a wet material that I can sculpt and will dry to a nice base. Any suggestions on what to use? I could use plaster but that will add weight to an already heavy display. Ideally the material could have integral color (redish brown like the muddy matrix these eggs are found in), and some sort of a silty-sandy texture.

I'm curious as to what others have used, done, or could suggest for my project. Thanks!

[Auspex]

If its weight precludes plaster, it will preclude about any pourable material that comes to my mind.

Expanding foam insulation would be sturdy and light weight, and could be covered with natural looking "dirt", but it can be a bear to work with.

[Arch2000]

Plaster isn't out for sure, it's just with the weight of the eggs, the plexiglass box, and the base, I suspect I won't be able to move it off the table if I ever need to! I'm thinking I might be able to build a base with foamcore (even cut out a section for the eggs to sit in), and then cover it with a thin layer of the finish material that looks like the matrix/sandy mud

[xonenine]

if it was a renovation where weight was a factor we'd use Structo lite plaster, it is an inexpensive material. I'm sure it could be stained a matrix color and then ragged/sponged/sculpted while drying to make the base of your choice, the eggs themselves could be protected w saran wrap and nestled right into the wet plaster, so they will sit nicely later.

[jpc]

i am a fan of spray foam. be sure to wrap your fossils in saran wrap before placing them onto the expanded but not yet set up foam. otherwise the foam willl stick to the fossils forever.