Aging Gracefully Sep 08, 2006 The past is gone but not forgotten and the future is far away; all we have is today. Optimizing New Sand and Core Sand Additions in Foundry Green Sand Systems Aug 17, 2005 The old rule for new/core sand additions is 300 lbs. per ton of metal poured, but that approach needs to be re-evaluated ? and made more exact ? for current molding methods and materials.