A finely divided copper rod structure has been prepared by the selective dissolution of aluminium from a Cu-50wt% Al alloy in aqueous NaOH. The aging behaviour of this product has been studied by measurement of the coarsening of the pore and copper rod structure. A decrease in caustic concentration or temperature was found to reduce the rate of coarsening. The leaching reaction was found to play no part in the coarsening process. A dissolutionr-eprecipitation mechanism, where copper dissolves from faults within the structure and reprecipitates on adjacent copper rods was found to account quantitatively for the development of the coarsening process in its early stages. However, this model breaks down after extended times when the rod geometry is destroyed.