Hi, I am a hobby silversmith and learned my first lesson regarding
setting opal. Use a soft bezel. I used pre-manufactured stepped bezel
which is very strong (I hoped that this would protect my stone better
once it is set). Although being very careful since I knew that opal
is sensitive the stone cracked at the very end of the setting
procedure. While I was thinking about which resin to use to rescue
the piece I read the opticon thread and wondered if this is the right
solution. The stone is an elongated oval (5x10 mm) and the crack runs
across the short diameter. The pieces are otherwise securely set, and
you can barerly see that it is actually 2 stones now, but I know it’s
there and that bothers me.
If you have broken the stone and plan to sell it you need to replace
the stone. If you sell this to a customer and do not disclose the
breakage then you are in violation of all kinds of ethical standards
and quite possibly some local and federal laws. If you plan to keep
the piece yourself than any type of epoxy will probably do the trick.
Opticon will not hide the crack in your opal. It will keep it from
progressively getting worse. The best approach is to remove the
stone, use a spot of supper glue to hold it back together in it’s
original shape. Then using a fine, 0.004" or 0.006’ diamond blade,
saw out the crack, leaving two parallel faces. Saw from the face of
the stone to the back. This will lessen the chipping on the edge of
the saw kerf. Now roll out a piece of gold the thickness of the saw
kerf, and epoxy it in place, being careful to keep the alignment of
the opal. You can finish off the gold and touch up the opal surface
after the epoxy had hardened, at least 24 hours. Now you have a
piece that looks good, and should give you few problems as it ages.
To prevent cracking an Opal when bezel setting, you have to make sure
that the bezel plate to bezel wall is clean, no lumps of solder,
nothing that will provide a high spot to cause you problems.
Secondly, make sure the opal doesn’t have high spots or a sharp edge
on the girdle. If it is a closed back setting, bed the opal with
either a thin layer of epoxy or some fine hardwood saw dust. The
first is my choice. Make sure that you don’t have any epoxy above
the girdle and that there is none on the bezel walls. After the
epoxy has set, then bring down the bezel onto it. No, you are not
gluing the stone in place, just providing a little safety cushion for
it.
Hi Isabella, Opticon is usually used on stones before they are cut, to
seal fissures and cracks. In my frame of reference, I’ve never seen it
used to repair a broken stone. I assume you also want to leave the
stone in place, now that it’s set? A better choice probably be a high
quality clear epoxy (sparingly and carefully applied), or a super glue
type adhesive. There is one called “Zap-A-Gap” available through
jewelry suppliers that would probably be ideal.
Although being very careful since I knew that opal is sensitive
the stone cracked at the very end of the setting procedure. While I
was thinking about which resin to use to rescue the piece I read the
opticon thread and wondered if this is the right solution.
Dear Isabella, I don’t know how other Orchidians will respond to
your Opticon question but here’s another way you might be able to
approach the cracked opal problem. If your design allows, you should
be able to cover the crack with a strip of silver (possibly textured,
pierced, scallop-edged, whatever) the ends of which you’ll tuck into
the bezel. If necessary, you can glue the silver “design element” to
the stone or into the bezel as well. I’ve done this once or twice and
it can look great, as if you designed it that way from the beginning.
(Of course, if this solution doesn’t work in your design, you’re back
to opticon or replacing the stone.)
The pieces are otherwise securely set, and you can barerly see
that it is actually 2 stones now, but I know it's there and that
bothers me.
I know just how you feel – had a large opal with a lot of matrix
crack on me, and it broke my heart. I agree with Susan’s advice, and
that’s what I did with mine: I made some gold foil and placed it
between the two parts, then set them just as if they were unbroken.
The result was good, and if someone jumps to the conclusion I did it
on purpose, fine by me.
All, I have helped jewelers repair many opals broke in half or broke
into two large pieces. The best way to do this is to grind the two
parts of the stone with parallel, flat edges. Then glue a piece of
gold or silver between the two pieces. The finished piece goes right
back into the same mounting with a unique look. Repairing a broken
opal by adhering the pieces back together is not an ethical practice.
I refuse to do this when asked. A broken stone should be recut,
replaced, or fixed as mentioned with the customers knowledge and
agreement.
As one who has messed with alot of opal, I’d say your stone has lost
most of it’s value without recutting. If you want to go ahead an use
it, Opticon is totally inappropriate. Opal is very heat sensitive. I
would say your best bet if epoxy, but that will be relatively
difficult to use. The easiest and most reliable fix for a few years
of use under light handling would be a very light weight superglue.
By light weight I mean one that flows easily.
You need to get the fit of the pieces as close as possible, but if
you don’t quite get it the first time, don’t despair. Put the stone
in acetone and wait until if falls apart again. This could take
several days. Then clean both pieces with soap and water, rinse
thoroughly and try again.
There have been numerous attempts to “fix” opals using polymers.
Some ar e much better than opticon as they have a refractive index
almost identic al with opal. Aside from the ethical problem, these
solutions are only t emporary. Sooner or later the mended break will
reappear due to differen tial thermal expansion. Over time, the opal
expands and contracts at a r ate different from the polymer resulting
in a flaky and very visible crac k.
Repairing a broken opal by adhering the pieces back together is not
an ethical practice.
Gerry, I respect you a great deal, but for the first time I have to
disagree with you. It depends on the situation. If it is a piece being
sold in a jewelry store, or as a new piece of first-rate jewelry, this
statement does apply. If it is a piece of personal jewelry or heirloom
or something not-for-sale, I would disagree.
If Aunt Martha whacks her opal on the kitchen sink, or a student
cracks a stone setting one of his or her first bezels, I feel cosmetic
recovery is not unethical. If they were to turn around and sell that
item on eBay however (to intertwine another thread), that’s another
story.
I’ve seen the strip of metal in the stone (or over the crack) to
recover from a break, and it always strikes me as, “Gee, someone broke
a stone…” I would rather replace the stone with a new one (maybe use
the old one for inlay pieces) or cosmetically repair it to look as
uninjured as possible.
Just one person’s opinion. I still appreciate and respect yours!
Dave and All, The reason I say it is unethical to glue an opal back
together is based on experience. Every time I have done this it was
with a large, expensive stone that had either cracked from the opal
being unstable or damaged by impact. Each time the person said that
they would not resell the opal after it was opticoned. They lied. I
received news that every piece I had repaired had been sold. No one
wants an opticoned opal. Once broken or unstable the value of the
piece is minimal. Now I either repair the stone with metal so that
the repair is visible or replace the entire stone with a new one.
Gerry Galarneau
