Castable materials are materials that are mixed or melted and then poured or cast into a mould while a simulator is being built, rather than bought in a finished shape. What they have in common is the step, not the chemistry: a builder measures and combines components, pours the result into or over a form, and waits for it to set.
This page is a pointer. It carries no build instructions, quantities or costs — each material below has its own page where those live.