The use of a superabsorbent polymer to prepare water-equivalent volume standards by solidification without the need of irradiation to effect the polymerization process, is described. Less than 40g of the polymer is needed to solidify 1litre of solution. Monte Carlo simulations of the gamma-ray escape probability indicate that the mixture is water-equivalent to better than 1.0%. During preparation, the solidified material can be mixed until homogeneity is achieved. Comparative measurements made before and after solidification confirmed the homogeneity and demonstrated water equivalence.