Silver 950 and 960 Information
On this page you’ll find information about the hybrid clay mixes which includes silver 950 and 960 blends.
PMC Sterling Clay was launched in 2011. Many people are using the so-called 960 blend of half PMC Sterling, half fine silver metal clay (PMC3, PMC Flex or Art Clay Silver). This makes a strong clay that can be fired on an open shelf in the kiln. In June 2016, Bill Struve introduced his own blend of clay called EZ960 through Cool Tools. Art Clay 950 was launched in September 2016. PMC One Fire Sterling which doesn’t require carbon to fire was launched in September 2016. This clay was rebranded as PMC 950 Sterling in November 2018.
Content checked July 2021.
Update from Celie Fago and Bill Struve on Firing 960
In April 2016, Celie Fago posted this update on Facebook.
“Early last fall I began to raise the firing temperature for 960. Since the late fall I have fired all my PMC 960 at 1650F for at least an hour, believing that the metal is harder, stronger, and more fully sintered at that temperature. After seven months, I am confident that raising the temperature is a good idea.
In late winter I had a conversation with Bill Struve, who had also started doing tests on 960, believing that 1500F was not hot enough. His testing was more scientific than mine but we both came to the same conclusion; hotter is better. Bill’s research also suggests that a lower temperature (not lower than 1500) will sinter the 960 if the time is extended to two hours.
Kilns vary, so if you’re interested in raising the firing temperature on 960, do so in increments, or by using test strips until you’re sure of your kiln.
Celie Fago shares her findings from mixing PMC Sterling with PMC3 to create a strong clay which can be open shelf fired. This results in a silver object which is 960 parts per thousand of silver.
Metal clay artist and teacher Julia Rai tested EZ960 and Art Clay Silver 950 in August 2016. Here are her findings in a downloadable PDF document.
This clay gives you the ability to design stronger and bendable jewellery. It does not require activated carbon or multiple steps firing. Just put your dried pieces into your kiln at room temperature on a kiln shelf and full ramp speed to 800°C/(1470°F) for 1 hour. That’s all… You can take out your fired pieces while still hot. The shrinkage of Prometheus® Silver Clay 950 is 15%. You can hallmark your pieces as Sterling.
Testing Art Clay 950 Silver Part 1 and Part 2– Joy Funnell
Check out the experiments on Art Clay 950 Silver by Joy Funnell.