I ran another course of sterling clay through the kiln last night, technically finishing my Four a Month project on time, although I didn't do the patina until today.
I made a couple of small hollow-form heart pendants or charms.
This first one taught me to remember to protect openings from the carbon, as the carbon wedged inside the piece caused it to crack. I'll have to repair it.
This version utilized fine silver syringe work on top. It's not true that fine silver must be fired in air -- it works well! It IS necessary to remove the binder with oxygen available, for all of the metal clays in fact. But after the binding is gone, sintering takes place either open or buried in carbon. Fine silver and gold were the first metal clays manufactured because the pure metals don't oxidize when sintered in air. However, nothing untoward happens when they are sintered without oxygen, as long as the binder has been removed.
One interesting detail here is that the two hearts were cut from the same templates, but came out different sizes. I assume this is a function of all the fine silver line work, which doesn't shrink as much. I'll have to think about how this could be useful.