I teach jewelrymaking near-full time these days, and to break it down
in to easy to understand terms, I tell my students to imagine putting
a piece of bread in the toaster. Once the bread is toasted, it popped
out an d is nice and hot. Put butter on it and and it melts into the
toast. I tell students to think of soldering that way - the metals
have to be of same temperature before the solder will melt. I teach
my students to figure out the mass of metal, so that a heavier piece
of metal will need more heat and the smaller piece will need less,
and don't heat the sold er. Another tip I do is to tell students to
watch the white paste flux bubble, foam over and then become clear,
and that's when to add the solder. I've heard of people using a
Sharpie marker to make a mark and then when it disappears, it's time
to put solder on.
Another trick I do with bezels is that I flux and heat up the silver
or gold till the flux becomes clear, and then stick-solder my bezels
on the outside, so that I don't have solder "ghosts" on the inside
of my bezel s. I rarely have extra sheet metal sticking out like a
picture frame for I prefer a very clean look.
I've learned to put jewelry terms into everyday layman's terms so
that students can relate to metalworking better, since so many of
them only take jewelry for fun and a few do go on to make it a
serious hobby or go into business.