Last night there was an incredibly informative class/discussion about a new metal clay product put out by Mitsubishi Materials called PMC Pro. It's an alloy of fine silver and copper. 90% silver, 10% copper. Those are the same proportions used in Coin Silver.
Wikipedia has a really informative entry on the variety of silver standards that are used around the world. The 92.5 that we're used to calling Sterling and that we feel comfortable using as the "go to" white metal is just one alloy that is available to jewelry makers. There's been a real resurgence of interest in Shibuichi - 95% copper and 5% silver (although I know that isn't considered "white" by any stretch of the imagination). Reticulation silver is (generally) 82% silver and 18% copper. Mexican silver is 95% silver and 5% copper. There are all kinds of wonderful metals available to make beautiful jewelry with.
So why has there been such a hubbub online in the past few days about this new offering from Mitsubishi? It's an unknown? People don't like change? It's an election week and distrust in in the air? I don't know, but what I do know is that last night's class was a wonderful introduction to a new material presided over by one of the most respected people in the metals world (clay or milled) and "assisted" by three other incredibly talented and knowledgeable artists. None of whom are on the payroll of said manufacturing company by the way.
Rings by Celie Fago. See how narrow the shank is on the signet ring? And the laced ring is only 3 cards thick!
Tim McCreight, Jeanette Landenwitch, Barbara Becker Simon and Celie Fago generously shared all they've learned in their explorations with this new material. Making the learning curve shorter for the rest of us.
From Tim we learned that this new alloy was developed, as is, because Mitsubishi wanted to meet a number of standards that they felt would make Pro an attractive product. They were looking for tensile strength, stretchability, bending strength, surface hardness (resistance to dings and dents) reasonable firing schedules and methods, and beauty of color. They tried all sorts of alloys, including sterling, and this is the one that met the majority of their pre requisites.
Rings by Patrik Kusek
From Jeanette we learned that enameling is possible with this new alloy with the added bonus that you don't have to depletion gild it! From Barbara we heard that she has not quite figured out how to judge the shrinkage when making her gorgeous bangles. One came out too small (bonus for her daughter) and one came out too big. Which was actually a blessing, because in trying to fix it she learned that it is oh so easy to attach fresh Pro to fired Pro with some homemade slip. Good to know! Celie will be making all her hinges and catches with Pro from now on. It's so hard and strong that her beautiful curly box catch doesn't flex at all when snapping shut. Although the one previously made with PMC3 - does.
This one was made with PMC3, but I couldn't find the image of the new one online.
There was so much more. The information flowed for an hour and a half. And if I had any kind of a good memory, I'd most likely be sharing more of what I heard. But taking a class is so much better than waiting for information to trickle through the cyber pipelines, isn't it? That's why I paid my money the first day the class was announced. The class was sponsored by Rio Grande and PMC Connection (the only two importers of PMC) and since I'm a senior instructor my money was refunded and I got to listen in for free, but I would have been happy to pay for the wisdom.
I'll leave you with some of the bullet points about PMC Pro and hope you'll give it a chance. It's not for everyone. It's much better for some techniques and perhaps overkill for others. It's more expensive due to the manufacturing process, but so are ready made sterling tube, bezel wire, sheet, earring wires - etc. It's a really interesting addition to the alchemy that is metal clay and I can't wait to try it!
- Fire to 1400ºF in carbon for one hour. Fast ramp. No nonsense.
- 1/2" spacing between pieces and the bottom or top of the carbon layer. A US nickel is about an inch, so half of Jefferson's face should be buried.
- PMC Pro can be used along side PMC3 but the two should NOT be blended to make a different alloy. Fire for 30 minutes in an open firing to burn off the binders in the PMC3 and then for another 30 minutes in carbon.
- Use only easy or medium solder on finished pieces. The melting points of hard solder and PMC Pro are too close for comfort.
- Make your own slip by adding water to the Pro clay just as you always do with the other formulations. Tim added some lavender oil to make it nice and creamy.
- If you let the fired pieces cool in the carbon/container they won't oxidize.
- You can use the same tools you always use, but not the same sanding supplies.
- Shrinkage is between 15% and 20%.
The PDF notes that were e-mailed to attendees of last night's class have also been uploaded to the PMC Guild website. Look for a great way to make your own firing container. Happy learning!