Liquid latex is ideal for making "glove moulds:" thin-walled moulds that closely follow the shape of the original model. It is more convenient to use than some other mould-making compounds because it is usually made as a one-part, air-cure compound that doesn't require mixing. While latex glove moulds are fairly tear-resistant, they are very flexible and typically need some kind of supportive "mother mold" to support them while casting concrete or plaster into them.
Place the model to be moulded face up on a flat surface. Open the bucket of liquid latex and use a paint brush to cover the surface of the model with a thin layer of latex. Allow the latex to dry to the touch, about 30 minutes.
Continue to apply layers of latex to the model until the mould is as thick as you want it, allowing the latex to dry between each coat.
Mix the two-part mother mould compound in a clean container, according to the ratio recommended by the manufacturer (usually about three parts resin to one part hardener.) Mix thoroughly with the spatula.
Apply a coat of the mother-mould compound over the latex mould with the spatula. Allow the mother-mould to completely harden, about 2 hours.
Remove the model from the latex mould and mother mould. The mould is now ready to use.
Because latex moulds are so flexible, they can be used to cast complex three-dimensional shapes; once the cast object has hardened, the mould can be peeled away from the object, much like a rubber glove (thus the name "glove mould.") Latex moulds are best for casting hard substances such as concrete and plaster. Epoxy resins can be cast in latex moulds, but the moulds don't last as long in this case.
Do not apply mother mould to a latex mould of a three-dimensional model. It will prevent you from removing the model from the mould. Mother mould compound typically stays workable for less than 10 minutes after it has been mixed. Make sure you have your materials in place and your latex mould ready to be coated before you mix the mother mould compound.