Insoluble raw materials (oxides, carbonates, oxalates) were milled in deionised water using zirconia media in a Fritsch Pulverisette 7 planetary mill. An ammonium polyacrylate dispersant was used to reduce suspension viscosity and a water-based acrylic emulsion binder was added to increase the mechanical strength of the discs after drying so that they could be isopressed to increase their density and would remain intact through subsequent calcination and embedding. Each mill generated 15 cm 3 of aqueous suspension with a known content of inorganic precursor per unit volume. The solids contents were checked by drying a 1 cm 3 sample taken from each mill in an oven at 80 °C overnight and this measured solids content was used to calculate the weight and molarity of inorganic precursor per unit volume of suspension and thus the volumes required in the later dispensing operation.