I've a paper to write for my grad class, so I need to be quick.
I spent three hours yesterday, with two mates, casting figures. Not one head or musket came out properly. Even after I cut vents and drilled holes for venting in one of the molds.
After a while, we all noticed that the metal seemed to be too cool, even though I had turned up the heat knob.
As I do not yet have a thermometer for the pot, the one I ordered will take nearly a month to arrive (sigh), I could not verify the temperature, but I believe all of my casting woes are due to an inconsistency in the temperature of the metal.
I will likely be returning the casting pot and getting a new one...but I have 20 bars of metal still in the pot that will have to come out first.