This paper proposes the use of a copper disk as a simple heatsink for planetary mills in order to limit or slow down the temperature increase during prolonged grinding. A series of grinding experiments have been performed in which the surface temperature of different parts of the grinding bowl has been determined as a function of grinding time. Three different experimental series were conducted: a reference series without the heatsink, and two series where the heatsink had been given the respective initial temperatures of 25 degrees C and -25 degrees C. As demonstrated in this paper, the proposed concept represents a cheap but effective way of limiting or slowing down the temperature increase occurring in the grinding bowl. The effect is of a magnitude that can be of considerable practical importance, and the concept can be employed on most planetary mills where the grinding bowl holder is designed to accommodate different bowl sizes. (C) 2009 Elsevier Ltd. All rights reserved.