Google+ post by Kris Schall on 2013-05-16 00:26:54 UTC

The placement of the feed systems kind of puzzles me. If both the feed and the vent on the other side are on the bottom, how can the air at the top of the casting actually escape the vent?

I wondered the same thing watching this. The only conclusion I could form is that the mold was gas permeable.

Most of the time I watch “how it’s made” etc sprues are right on the top of the casting.