Cast or injection moulded makes little difference to hydrolysis resistance at room temperature.
Cast acrylic is commonly used in bath tubs.
Extruded acrylic is commonly used on roof sheeting.
Cast acrylic is sometimes used as fish tanks.
Cast and extruded acrylics are commony used in outdoor signs.
Cast and extruded and injection moulded acrylic are extensively used on automotive and aircraft and marine exterior components like lights and windows and weather shields and headlight protecrors.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &