SilverOtter

13 hours ago, LadyWYT said:

Welcome to the forums!

Smelting doesn't require a room; you just need to make sure that nothing can put out the fire under the crucible. And as @Vexxvididu already noted, the fuel you're using needs to burn hot enough, for long enough, in order to smelt the ore. It is possible to "coast" on coals, but if the temperature of the ore drops you'll lose your smelt progress and have to start over. Another thing to keep in mind that in regards to alloys, you need the proper ratio of ores in order to achieve a smeltable product; if there's no viable output the ore won't smelt. Also, the more ore you try to smelt at once, the longer it will take to smelt, so the ore can be hot enough to start smelting but you may not see any progress on the meter for several seconds, as it takes a fair amount of time to smelt large quantities of ore.

In any case, charcoal is sufficient for smelting copper and zinc, so the first things to check are ore quantity and ore ratio. Given that you said the meter still reads as "cold" despite the fire burning at maximum charcoal temperature, I would suspect that you have the wrong ratio for the alloy you're attempting to smelt(brass).

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?