<prompt> The cast should not be stored above:50 C55 C40 C45 C  <response>: If the storage temperature is raised to between 90C and 110C 194F to 230F, shrinkage occurs, along with loss of strength as the water of crystallization is removed and the dihydrate reverts to the hemihydrate form. As a rule of thumb, it is not safe to store or heat a stone cast in air at a temperature higher than 55C 130F. Phillips Science of Dental Materials ed 12 pg 192 