I got this from this article online: http://www.ganoksin.com/orchid/archive/200112/msg00051.htm
To make soldering jump rings easier you might try this technique: roll out a narrow strip of solder in the rolling mill or cut and pound a strip of solder very thin. Cut the strip into small snippets. Insert the appropriate size snippet into the seam of the jump ring using tweezers or pliers, (it should be thin enough to not force the join open). Heat the joint until the solder flows. It makes a perfect seam every time, as the solder cannot jump to one side and flow away from the seam. This isn't practical for soldering dozens or hundreds of jump rings at a time, but if you need to control exactly where your solder flows this is a handy alternative to using a solder pick.
1 hour ago