Aluminum casting made of 356-T51 (V process) is kind of acting "gooey". We get lot of cases of threads stripping. Granted aluminum casting is not the best material for internal threads, but we never had such stripping problems in the past made from the same aluminum alloy from the same casting house. Is there any testing that I can do to find a difference between past (good) castings from the present (perceived as gooey) material ;?