Urchin shells

I have some urchin shells that I plan to use for Christmas ornaments. They are very fragile & I’m wondering if coating the insides with thin CA would help to stabilize them. Has anyone tried this before? I would appreciate any feedback or experience you might have with these.

Duane,

I have used an acrylic spray on the outside of them myself.  I have heard of applying slow expanding insulation foam to the inside of them as well, before adding finials.  I personally think the CA idea would work, but it would be an expensive way to go about stiffening them up.

Can you buy CA by the gallon?

I'm sure it could be had somewhere out there I have to wonder though if the CA would stain the shells like it sometimes stains wood.