Sizing a ring without taking the pearl out is asking for trouble down
the line. I used to try it but ended up somewhere down the line replacing
that same pearl one way or the other if it's an expensive ring
especially. If you can get it off using something like attack or
something similer then steam it off, but unless you have a pearl maker in
the back of your shop ALWAYS remove that pearl.
Not that bad. The trick is simple. Take an old tuna fish or cat food can
(empty, of course) or similar container. Fill with water. fit your
sizing seam, and hold in your third hand tweezers so that the pearl, along
with the whole upper half of the ring, is under water. Solder the seam
this way. You’ll need a torch using oxygen and fuel gas, rather than the
cooler gentler types like air/gas or prestolite, if the ring is silver or
heavier gold. But I guarantee that done this way, the pearl will never
exceed the temp of boiling water, and it won’t be damaged by that at all
(any more than the above recommended steam, which can be a good deal hotter
than plain boiling water). Only with the heaviest rings, especially silver
ones, or those where soldering must be done somewhere other than the bottom
of the shank, should it really be needed to remove the pearls. Taking them
off is not always without risk either. If they happen to be glued on with a
super glue, attack won’t work so well… I’ve seen more pearls damaged by
people fighting to get them off a ring, than damaged by leaving them in, IF
proper means of heat sinking the pearl and the top of the ring are used to
protect the pearl.
There are variations. Some folks, instead of just water, use wet sand.
Others wrap the pearl and the top of the ring in tissue paper (kleenex)
than dip in water to create a mass of wet goop around the top of the ring.
Or you can use the commercial heat sink compounds like cool jool. But the
important thing to remember is that it’s the water, and there must be
enough of it, that does the job. Too little, and transmitted heat up the
shank can dry out the heat sink and then the pearl is in danger. That’s
why I use just plain water in a whole little can of it. Always enough.
Done with care, this even works with things like rings set with amber. If
you think pearls are heat sensative, you’ve never worked with Amber (grin).
Now, it’s important to remember that you not only need to preserve the
pearl, you need to be sure it’s properly glued too. If the pearl was
correctly glued, there will be no problem. But if poorly glued, or not
clean, even slight heating (whether from the steam cleaner or from sizing
as above and having the water get hot) can soften or weaken some glue
joints, especially epoxies. So its a good idea to check that the pearl is
tight after you’re done. If it was going to loosen anyway, then sizing is
as good a way to loosen the glue as attack. If, after everything is cool
from sizing, the pearl is solid, doesn’t wiggle or turn, then it’s fine.
And, in Matts favor, it should also be mentioned that pearls CAN be
damaged by other than heat. The pickle, some cleaners, polishing, etc, can
damage some pearls. So for these getting them out can be preferred.
Unfortunately, getting the most fragile types (like mabes) out of a ring
can be the trickiest, as often they are assembled and trying to remove them
will disassemble them instead… So use your head. In many cases, the
easiest way, sizing as I’ve discussed above, will be safe and reasonable,
without subjecting you or the ring or the pearl to any more risk than
needed. But make the decision on a cautious and conservative evaluation of
the rings needs and your skill level, not your own desire to be done
quickly. Then you won’t be taking undesireable risks.