Claycrete.
Claycrete is an instant Papier Mache that's easy to prepare and model and dries exceptionally white at room temperature.
Mix only as much as can be used in 1/2 hour of modelling time.
Additions of more Claycrete are possible at any time during the modelling process.
Claycrete will not stick to your hands or tools, making it exceptionally easy to work with.
Claycrete dries best slowly at room temperature, however drying time could be shortened if dried in the sun or in an oven at 150°F (65°C).
Claycrete must be thoroughly dry before painting or decorating.
Work can be messy so best to protect your work surface with a tarpaulin sheet.