SilverOtter

Thank you! It was the wrong ratio, my bad. Somehow got it in my head that a 50/50 ratio would work, silly me.

Because of the way I laid out my smithy, it doesn't count as a room. Recently I was trying to smelt some nuggets (copper and zinc) in a crucible, but even when the crucible had reached max temp for charcoal, the green arrow never started filling, and even said "cold" near or in the arrow. I tried to enclose the smithy somewhat (still didn't count as a room, checked with /debug rooms hi), and the arrow no longer had the word "cold" near it, but it still didn't fill with green and my ores still didn't heat up. Is this a condition of subzero winter temps, or a bug?