The resource of stuffing box seal is determined not only by the unit design and by the conditions of its operation, but also essentially depends on the correct choice of stuffing box packing. Not one of stuffing box packing manufacturers does not provide data on mechanical properties. Therefore, in this paper the results of experimental investigations on determining the mechanical properties of packings are presented. The obtaining mechanical characteristics allow to clarify existing methods of calculation and to increase sealing and durability of stuffing box packing seals.