The paper investigates the compression strength of samples of regenerative polymer mass RM 101 Resimetal Metal Repair Pasta manufactured by Rendor. The effect of weather conditions on selected mechanical properties of the tested mass is examined. The samples are subjected to seasoning at room temperature, in an environmental chamber, and in a thermal shock chamber. The samples for strength testing are made according to the adopted method. It has been observed that the samples seasoned at room temperature have the lowest strength, while the highest strength is exhibited by the samples subjected to seasoning in an environmental chamber at a temperature of 70°C and humidity of 95%. In addition, the paper compares the strength properties of regenerative polymer masses manufactured by Chester Molecular, Belzona, and Unirep, as well as of the widely used epoxy compound Epidian 57 mixed with the Z-1 curing agent with those of the Rendor mass. The properties of the above masses are obtained from the available literature.