Warning: I was pouring a simple aluminum bracket wrong for a decade
For years at our foundry in Dayton, I'd just dump the metal straight into the mold from the crucible. About six months ago, a new guy from a big shop in Detroit watched me and said, 'You're pouring too fast, you're trapping air.' He showed me to tilt the crucible slowly and pour along the side of the sprue, not the center. I tried it on the next run of 50 parts, and the scrap rate from porosity dropped by half. Has anyone else had a basic pouring technique that they had to unlearn?