The auto body filler based on M28# resin is excellent in workability, air-drying, sand-ability, adhesion and storage stabilit M28 ... The auto body filler based on M28# resin is excellent in workability, air-drying, sand-ability, adhesion and storage stability. ... % Cobalt2 (10%)Recommended Storage: The resin should be stored in closed containers in the dark at temperatures not exceeding 25 , and typical ...