No.
Just.... No.
A) low melting point (200C range) solders are not suitable for jewellery repair (and I bill a lot extra when I get jobs like that because I have to remove the stuff first) and B) the temperatures required for jewellery solders are in the 800-900C range. Done with a blowtorch.
Plumbers mats aren't good at preventing heat transfer, they're more flameproof. Try using that as protection on a person and you'll be looking at charges of GBH (because they can't consent to being injured).
The ONLY ways to join something that someone is wearing is with either with a pulse-arc welder (like a PUK) or a laser welder (by which I mean jewellery scale, not Dr No). And even then it's all kinds of bad idea.
Bookmarks