Hi, I've been experimenting with PMC3 silver clay and would like to combine it with some of my beads. I tired a little tester and fired a bead with silver clay on it. The clear glass yellowed slightly where the clay made contact with the glass. I understand that this could be because I didn't clean the glass enough around the glass and the residue has burnt off and marked the glass? Or maybe the firing was just too hot and the silver on the glass scorched it? The silver clay also did not appear to harden sufficiently, remaining somewhat fragile and snapped. I understand from reading various posts, the reason the silver did not harden up sufficiently is because it did not reach a high enough temperature for long enough.
I've searched for a definitive guide of the highest temperature that an annealed bead of COE104 can be fired at and for how long. Guidelines for PMC3 are that you should fire at 1650 f/898.88 C for two hours for optimum strength (obviously depends on the size of your piece). This is obviously not possible when you are combining glass. I tried firing at 1110 f/598.88 c for 30 minutes, but this doesn't appear to have been hot enough or possibly not long enough?
If anybody has any experience and has found a successful formula, I would be really pleased to hear from you.
Thanks
Julie
I think the minium temp for the metal clay is 650 degress C.
I have fused it with bullseye glass but not 104 before.
the yellowing can be a reaction between the silver clay and the glass, depends on the colour of the glass, some colours dont like the silver clay.
Hi
I posted this in another thread. Have a look at this tut. It gives the temperatures that work from the point of view of the the silver lay firing and the glass not distorting. It is important to use the overlay paste first as it makes the clay stick to the glass. I would also say hat it is bettere to keep the silver fairly thin so that it fires properly. Hope that helps.
"I followed Rocio Bearer's tut very successfully https://www.theflowmagazine.com/index.php?option=com_k2&view=item&id=808:tree-of-life%E2%80%94a-new-beginning-in-glass-beads&Itemid=63&tmpl=component&print=1 (https://www.theflowmagazine.com/index.php?option=com_k2&view=item&id=808:tree-of-life%E2%80%94a-new-beginning-in-glass-beads&Itemid=63&tmpl=component&print=1) Just remember to clean off the glass when you have scraped off the unwanted overlay paste or, in my view, don't put it where you don't need it. Also remember that the silver will fume some glass and change its colour."
Wow what a prompt response. Thanks I'll take a look at the link.