Hi Michael, A “Hot Spot” is an isolated thick spot. For example,
a square ring with a round finger hole has 4 Hot Spots. Some
pieces are tricky to figure where all the spots are. Thats why I
recomend using a millimeter degree caliper to thoroughly map your
piece to identify all spruing locations. Some folks think this is
too extreme and rely on a particular alloy to get arround this.
Sometimes it works, but the folks who want to cut corners to save
a few bucks are the first to return a piece for a refund when
they find porosity. J.A.