Squeeze sand mold *Annoying short format with annoying music https://youtube.com/shorts/xQuvY_cFP2c?feature=share
It was interesting to see when the person in the righthand side of the video pours the molten aluminium and it swirls around the sides of the spue sucking in air. A straight sided large sprue is also used which is supposed to be not used as it will suck in air yet they get good castings.