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Unmounting cabachon set in a bezel?


#1

Hi all,

Need to do some soldering work on a piece of 14K jewelry and prefer
to unmount the stones (2 14X12 opals) rather than risk them being
effected by the heat. Bezels look real tight to the stone and the
only thing I think i can get in there with is a knife blade (or other
implement?) and try to pry the bezel away from the stone, or worse
yet, cut the bezel open, remove the stone and re-solder the bezel,
hoping I did not make it too small for the stone.

Any other techniques for removing the stones?

Thanks,
Angelo Giaimo


#2

Hi Angelo,

I use a new razor with a reinforced back to slowly wedge it between
the stone and the bezel. I slowly work it around and bend the bezel
further out away from the stone until it is loose enough to drop
out. If done carefully I have had great success doing this. Sometimes
it will bend the bezel some and distort it, but before resetting the
stone I try to clean up the bezel by reforming it and polishing it
out. Then reinstall and the bezel. It can generally be able to be
pushed and burnished back to very near original condition. I do this
about 3 to 4 times a month and have had no problems I could not fix
and make it look as good a original.

Ken Moore
www.kenworx.com


#3

I wouldn’t even try to pry open the bezels, not with opals anyway.
Either cut them off or if you have sufficient access you can use a
very thin cut off wheel to just slit the bezel open, vertically in
one spot (OK you could use a regular saw too). Now you have something
to grab when you open it. But you will need to fill in that gap when
you reset so its a judgement call on whether to do that and or just
replace the whole bezel as a matter of course.

If you make the new bezels slightly oversize you are guaranteed to
have bezels that are not too small. An amazingly simple solution to a
problem that gets frequent angsty mention.


#4

Angelo, When you remove a bezeled stone by sawing it open, do so
from the side, spread the bezel and remove the stone. This works best
if there is no back plate but can still be accomplished. After doing
the repair, use a small piece of sheet metal that is as close as
possible top the width of the saw kerf, close the bezel onto it and
solder in place. Then remove excess metal from the inside/outside of
the bezel. This returns it to its original size. I have used this
technique hundreds of times.

Cheers, Don in SOFL.


#5

Hi Angelo,

That’s a tough call. Any chance you know anyone that has a laser
that would be willing to do the soldering portion of the job for you?
That should be way less risky than removing and resetting the opals.

If not and if you can get to it with a saw frame, it might be best
to cut the bezel sides into quarters, perpendicular to the stone and
bezel (try not to touch the stone when the sawblade cuts through).
Then you can pull each quarter bezel out with relatively little risk.
Don’t touch the stone with any tools when pulling the bezel back, and
don’t try to pry it loose if it is stuck in the bezel, even if it
looks like it should just drop out. Cut it some more if you have to,
then cut it even more if you still have to, until it does just drop
out. Make sure that when it does fall out, it doesn’t fall onto
something hard. You will have to make a new bezel, but you probably
will have to anyway, no matter how you remove the stone. I consider
the bezel to be expendable, the stone is not.

You might be able to lift the edges of the bezels without cutting
it, but you have to be extremely careful that you don’t touch the
stones with any tools whatsoever and especially avoid prying up on
the bezel using the stone as a fulcrum It will surely break. I would
use a flat bottom graver, and push into the edge of the bezel from
the stone side, away from and above the stone, in several places,
working my way around. I can’t stress it too much, you must not touch
the stone with a tool! If the bezel is tight, even when you get it
pulled up, it may still not come out without pushing it from the
backside, and that can be very risky as well. If someone cheated,
and stabilized it with a little glue, it will be even harder to get
loose, you may have to use heat to soften the glue, putting the opals
at further risk.

Sure would be easier to find a friend with a laser to do the
soldering part.

Dave Phelps


#6

Knife blade and pressure to open a bezel can be dicey even with a
tough stone like onyx. I use a homemade tool consisting of a thin
strip of spring steel, say 0.5mm thick and 3 mm wide set into a
wooden handle, shaped to a U, ground knife sharp & polished, and
rounded on the back. With the flat side against the stone and the
rounded back against the bezel this spring steel “tongue” is gently
pushed between stone and bezel and rocked from side to side in a
twisting motion. You can lever the bezel open all the way around the
stone this way. But it is not without risk. To do this on a chippy
stone like an opal is asking for serious trouble. Sawing the bezel
open I think is by far the safer way.

Cheers
Hans Durstling
Moncton, Canada


#7

Rather than cutting the bezel down the side to split it open, cut
off the top of the bezel all around the stone using a fine saw blade
and/or a flat graver. This can be done with precision and poses
little risk to the stone. The original seat will be intact. Then
make new bezels, solder them on and set the stones in the new bezels
as a necessary part of the repair.

This amounts to a lot of work for you and expense for the customer,
but the customer must accept that you choose the method that poses
the least risk to you. If they are solid opals they may be very
precious and even irreplacable. If they are doublets or triplets
they are less valuable but more fragile. Look very closely to see if
they are simply glued into the bezel. Dissolving the setting glue
will also dissolve the glue layer in doublets and triplets
effectively killing them.

Opening a bezel by pushing with a graver or a knife blade is high
risk to the stone because there is always going to be a wedging
action against the stone. It can take longer to do than cutting off
the bezel in the first place because the bezel can be damaged in the
opening-up and you may have to replace it anyway. If the bezel is
paper-thin it will split. If it is hammered closed then forget it
completely…you will have to saw it off.

The laser and the pulse-arc is a Godsend for this sort of repair
because the heat zone is fractions of a millimeter and stones are
almost out of the equation. Depending on the soldering work needed
it may be better to subcontract the repair to a micro welder.

Alastair


#8

First of all, thank you to all who replied with suggestions.
Although I wanted to try to pry the bezel away from the stones and do
this all myself, I took the route of bringing them to a laser welder
(The Laser Connection on 46’th street in Manhattan) a referral from
one of my instructors at the Studio School, where I used to take
classes.

Did a real nice job. Just had to polish them up…and touch up the
bezel where I started to pry it away from the stone. Result was no
damaged stones and one happy customer.

Angelo Giaimo