I have the do it all flutter jig mold and I am having a hard time getting the tail portion of the mold to pour on the 1/4 size. It leaves a small portion on the tail side void of any lead only on one side. This jig has the wire form running through the center. I have tried different temps and heating the mold but still have problems. New to pouring jigs, another question is I hear about flux, why is it used, when do you use it, and what do you use. Any help is greatly appreciated.

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