This is the really damn cool part of the process. I enjoy the carving and designing, but in this part we get to play with metal that is so hot it’s gone liquid!
We started on Saturday night with a mini-session of mixing the investment. I still don’t know what “investment” means in this context, but I can tell you that it starts as a white powder that is apparently a mix of some fibrous material, and silica. You mix it with a specified amount of water and stir gently. It becomes a magic-mud consistency liquid, and you have to try to keep the air bubbles out of it lest you get air bubbles in your final cast (ie, a bubble on your ring). We gave it a little tapping to help release the bubbles.
The next day Russ started early at 9am by setting the temperature on his kiln to 300 degrees and waiting. I arrived around 11am, just in time to set the temperature to 700 degrees. Then we got started playing with yet another hobby (which I’ll write about shortly).
4 hours later, we set the temperature to 1350 degrees. Another 2 hours, 1100 degrees. Then we waited 1 more hour before getting to the good part.
The kiln and temperature controller.
Taking our very hot things out of the kiln.
It’s very hot in there.
Then we had a little problem. It turns out that we were out of acetylene, which is half of the required gas to create an acetylene torch, which is required to get silver hot enough to melt! Apparently we can’t turn the kiln off – the investment goes bad. We also can’t leave it for more than 6 hours, otherwise it goes bad. At this point, we were very close to losing what Russ estimated to be 16 hours of work!
We started calling people desperately. Russ asked me to point his propane torch at the silver, and then he ran off. We found out later that he’d driven to Home Depot to buy a mini acetylene torch which he hadn’t been sure he would be able to get, but about 20 minutes later the silver was melted from the propane (we also weren’t sure it was hot enough, hard to tell!) and he had plan B, a mini-torch.
We used the same swinging arm thing as the last time, melting the silver, winding the arm up, grabbing the investment with tongs, sticking it in front of the crucible and then letting go, allowing the sweet sweet silver to be thrown into the investment to form a ring.
The silver after we’d taken the propane torch away. It’s still a lot molten!
We did two rings this time, because Russ had his press-molded version and I had my carved version and we wanted to have both. Here they are!
Miranda was hanging around for this last, panicky, bit. She got to swish around in the bucket for a ring!
Next up, a lot of polishing! And gem setting.
No Comments