I would avoid expanding foam, there are health risks as well as the risk of 
breaking the specimen. I agree with Helena re coating the inside with paraloid 
B72 first. Then plaster of paris - or even better Jesmonite acrylic resin (it 
is more durable) - would be a good solid filler unlikely to pose health 
problems. You can set a threaded bar in the resin that you can use to secure 
the specimen to the base of your box with a nut on the bar on the other side of 
your box/shelf.

With best wishes, Nigel.

> Dear all
> We're wanting to source some sea-urchin shells for a feely box at Aberdeen
> Maritime Museum
> 
> Anyone know of a supplier?
> 
> Or do any of you lovely people have random, un-accessioned shells you might
> be willing to pass on?
> 
> Planning to fill the shells with expanding foam (gap filler) or plaster to
> make them more resilient to grubby, grabby hands!.... Anyone had success with
> something like this?
> 
> Many thanks - Helen
> 
> Helen Fothergill
> Head of Collections
> 
> Museums & Galleries
> Education, Culture and Sport
> Aberdeen City Council
> (M, Th, F) Aberdeen Maritime Museum, Shiprow, Aberdeen, AB11 5BY
> T: 01224 33 7704
> (Tu, W) Aberdeen Art Gallery, Schoolhill, Aberdeen, AB10 1FQ
> T: 01224 52 3712
> 
> Aberdeen Art Gallery open: Tuesday - Saturday 10-5; Sunday 2-5 (closed
> Monday)
> Aberdeen Maritime museum open: Tuesday - Saturday 10-5; Sunday 12-3 (closed
> Monday)
> The Tolbooth museum open: Monday - Saturday 10-5 (closed Sunday)
> Provost Skene's House currently closed to allow for the demolition of the
> neighbouring building
> www.facebook.com/AAGandM<http://www.facebook.com/AAGandM>
> http://twitter.com/AbdnArtMuseums
> 
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