i made a 14 gang angle iron ingot mold some years back.
the others just get used when i get that one too hot to handle and i want to finish off a pot of alloy.
the triangle shaped ingots stack up with far much less air space.
I seem to remember my ingots coming out blue and pink/purple ish the last I smelted and poured. Always thought it was the coating in my muffin tins burning off. Guess I’ll pay attention as I melt off some I need to do.
I plan on marking mine with a letter punch to designated what it is. Never had the need until now, but always wondered how everyone else did theirs.