This document describes a 1957 patent for a metal piston with an applied porous organic material layer. The layer, which can be wood or plastic up to 2mm thick, allows the piston to operate smoothly in piston apparatuses like hot-gas engines without needing abundant lubrication. This prevents lubricant from contaminating the working medium or clogging components. The layer is adhered to the piston, for example by gluing wood veneer, and provides a running surface that addresses the disadvantage of other organic piston materials having higher expansion coefficients than metal.