Tortoiseshell Box Conservation Series – A Domed Box With Cracked Shell

One of the more problematic considerations from tortoiseshell objects is found when the shell itself has been formed under heat, moisture, and pressure to a desired configuration for the object.  As a plastic polymeric material — and in the English language the word “plastic” is ambiguous, although in this context I am speaking in the materials science lexicon meaning the material can be deformed by thermoplastic forces and will retain that new shape once the forces are removed — tortoiseshell remains susceptible to fracture and other entropic phenomena.


This box has a lid that was made from a prepared tortoiseshell scute (plate) had been steamed then pressed between heated cauls (or dies) to establish its shape.  As a protein macromolecule the crosslinking bonds in the protein network has be reoriented by heat and moisture, and then reform once the heat and moisture are removed.  Thus once the pressed scute cools in the die-press and dries/hardens into its desired shape permanently.  The stresses from the forming process remain at bay for a while, but like I said is subject to cracking and distortion.


And that is what happened with this exquisite little box.  Stay tuned as I walk you through my treatment of it.