All Wintrebert’s inclusions are made of a resin called Methyl Methacrylate or Plexiglas, Altuglas,
Perspex, Lucite.

The resin is catalysed than heated to harden and support the weight of the chosen item to include – music instruments, exploded watches, divers, sailing models, fishes, etc.
A second acrylic resin is melted in the cast which is then put in an oven at 120°C for eight hours.
The heat welds successive layers together to hold it all in place.
It shrinks by 10% when it cools down, which means Wintrebert must sand and polish each side by hand to give it a neat finish.

Plexiglas being a solvent, many objects would melt in this process, so Wintrebert casts each of them in bronze or brass first in his foundry nearby.