I'm in the early days of trying out the new Art Clay torch-firable copper. While things are definately improving and getting better results each time, I'm still not always confident that something is fired enough.

So, my question is: Does anyone have any good tips for ways to tell if something is fired for long enough? I've had one experience already of drilling a hole in a pendant, which then broke easily into two pieces and was still crumbly on the inside. I don't want to risk breaking everything I make

Thanks in advance