Here's a question I was asked recently:"I'm soldering jump rings on to my fired pmc pendants and I'm having real trouble with the surface of the pmc popping and making bubbles as I'm heating the solder. It was fine when I fired the pmc so I can't understand why it's happening now, any one got any ideas?? It takes so long to make each pendant and they're being ruined at the last stage Thanks!"
Thankfully it's now sorted out and here's the solution for you! :)
The problem turned out to be quenching the fired PMC pieces prior to soldering.
Fired metal clay that has been washed, or wet in any way, can keep humidity for a very long time inside its pores. This is especially true of quenching which seems to force the water into the metal.. If that's the case then the fast heat up with a torch is the problem the moisture is trying to force it's way out.
Try going over your silver clay on it's own and heating it with a more gentle heat to drive out moisture then when soldering try and heat the whole area to even the heat distribution before a final quick focus on the jump ring.
Either that or you'd need to use easy paste solder and be very very quick with a fine flame (so the Metal Clay doesn't get heated)
Hope that helps
Nic x
What an excellent tip!!! Thanks for sharing.
ReplyDeleteThanks for the great tip. I don't solder jumprings onto my fired pieces, but lately I've been letting my pieces (that are comprised of separate metal clay parts) to cool on their own instead of quenching. I think if you're not in a hurry it's always better to let it cool on it's own.
ReplyDeleteHmm, I had this happen to me too today - if only I had seen this post earlier....! this turned out to be a quirky little piece because as well as the bubble, there is a very thin seep of wax or polish where I repaired a fine crack with a paste of lavender oil and then refired it. Now you cannot see the scratch but after several minutes of resting, there is wax along the exact same lines where the scratch was... have you ever experienced this?
ReplyDeleteI've never had that happen with a Lavender Oil repair...Maybe it was the Lavender paste?
ReplyDeleteHere's the "recipe" I make
http://pmctips.blogspot.com/2009/02/making-lavender-paste-repairing-fired.html
Nic x
Thanks Nicola - it is odd, my mixture has so far has done the trick even on rings that had split into two! I'm still not sure what caused this, but now I've washed it under the tap with a soft brush and a drop of washing up liquid and so far the line hasn't returned! Let's see what tomorrow brings... Love your blog btw - it's been a great help on many occasions! :)
ReplyDeleteThanks Jasmin,
ReplyDeleteGlad a bit of Washing liquid seems to have solved the problem :)
Nic x
I have been making fingerprint charms since last summer and all of a sudden I seem to be getting air bubbles rinsing in them when I fire. I am rolling clay into a ball and then flatening between my palms before rolling out so I have no Idea why all of a sudden I am having this problem. Any suggestions would be a great help. Thanks
ReplyDeleteAre you firing by torch or kiln?
ReplyDeleteIf you have got air trapped a slower firing (bring the temp ip gradually) might help