Add Berolic and other tackifiers in non productive stage, drop temperature should exceed 290F to 300F (143C - 149C)When mixing Butyl (Butyl, Cloro, Bromo etc) stocksAll tackifiers should be added in the NP stage. Never in the productive. Make sure that they are added in the center of the batchNever at the beginning where they can coat the door top, rotors etc and make them stickyDo not add Zinc Oxide in the non-productive stage