After two attempts at melting the same stuff in the cupola, I thought I should try it in a crucible in the furnace instead. After all, it's lost an awful lot of zinc, I figure I should treat it right some time. What especially allowed me to do this was the new welded stainless crucible I got from a friend, Castaway, which I already tried out on aluminum once, with okay results (the metal was gassy but that was probably something else). You can see that melt here.
Starting with leaves and lath, then moving on to some charcoal, I warmed up the furnace. There's not much charcoal nor air in there, but it's already damn hot! This stuff has a LOT of power.
Put the crucible in with some metal and packed it around with charcoal. It doesn't look very hot, but in another minute it'll be burning real good.
About 10 minutes and half a box of charcoal later, I took it out to see what the hell is going on. Within the first 5 minutes, it was already yellow hot - certainly enough to melt it... I also added a bit of borax and some glass somewhere along the line.
I took out the crucible, and HOLY CRAP! A big hole - nay, two holes in the thing! Guess I got it a little WAY too hot there. I blame this on spilled charcoal going in the crucible, can't see when it's melted. If I had been able to see, I would've been adding metal to melt which would keep it cool. I *really* gotta have propane. This photo shows the melted crud left in the bottom of the furnace (after dumping out the charcoal, etc.). Mostly borax and glass, probably a bit of clay/ash/etc. type fused stuff too.
Here's what happened to the crucible. I guess it brazed in a little too well, eh? :-\
- Well if that's what happened to the crucible, then what about the grate (that the charcoal was sitting on)..? Here's your answer. The melted side was towards the tuyere. The woven wire is about 1/8" dia., and thoroughly rusted out from a few decades in the basement.