I'm looking for a really soft end product using a gallon of Alumisol Soft Plastic. What is the ratio of Alumisol Softener that I would need? (Not going to use the whole product) Monica P. February 12, 2020 17:33 Updated Start with something like 2 cups Alumisol to 1 cup softener. Add more for softer, less for firmer. Comments 0 comments Article is closed for comments.