The paper outlines the construction and operation of a simple hot-pressing system that has been used to produce small volumes of yttrium iron garnet. The products have high density, a limited grain-size distribution and compare favourably with conventionally fired material. Simple changes in pressing conditions enable the sample porosity to be varied in a controlled manner, and results are presented indicating the way in which the most important loss parameter of the material for device applications, the effective linewidth ΔHeff, changes with these variations.