Hi Bob, in my opinion the cheap ring stretcher is probably not
the way to go - remember you can “tap” up the ring over the lower
part of the shank with your planishing hammer. Watch out for
hollow sides in the inside.
As for the solder problem, it sounds like you just need to
practice a bit more. First, heat your piece that you are about
to solder - solder definitely follows the heat, then add flux to
the joint. Second, wave your torch over your bit of solder and
pick it up with your solder pick. Don’t get the pick too hot
(this may be your problem). Third, put your torch back on the
joint about to be soldered and heat it up a bit more. While the
torch is on your piece, set your solder ball down on the joint.
At this point your piece will accept the solder nicely - it
should stick to the flux. Hope this helps, Mike