Cold shut/non-fill presents as an incomplete fill of the shell cavity, forming a puzzle-like section in the casting with a positive-negative junction. This defect indicates that the two metal streams met, but did not merge and completely fill. This is likely due to insufficient temperatures or insufficient permeability of the shell. 

 

The causes of this defect are evident in the shell, metal and other portions of the process. To cure these causes, R&R recommends taking the following actions.