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Having trouble setting cabs


#1

Hi everyone

I’m still having trouble setting cabs…here’s what I did I did a
basic rub over setting of a 14X14 druzy cab. I used .010" (thickness)
fine silver strip for a bezel. I was very careful with the burnisher.
I left the bezel a tiny bit higher than the edges of the cab
(thinking it would protect the fragile crystals). The result was
looking really good and then (as I often do) I went a little bit too
far in search of the perfect bezel. A tiny tear appeared in the top
of the bezel (coincidentally right near the solder line). There was
also a little buckling in the area near the solder line. The more I
tried to fix…the bigger the tear became.

  1. Was the bezel too big for the stone? It did rattle a tiny bit
    when i shook it :slight_smile:

  2. Was the bezel strip too thin?

  3. Should I use sterling instead of fine?

  4. Was the bezel too high and did this cause the strip to rub on the
    top edge of the crystals and rip? All of these are
    possibilities…can anyone recommend which to try first?

Thanks for any help…
Kim
Kim Starbard
http://www.kimstarbarddesigns.com


#2

Hi Kim,

If the cab is a high dome then the bezel needs to be higher to get a
grip on the steep sides of the stone; the bezel can be thicker
because it needs to be stronger and will not be bent much before
coming against the steep sides. With low dome cabs the bezel will be
bent at a sharper angle to get over the stone and grips securely with
less metal, therefore a thin bezel is appropriate.

Using a burnisher to fold the bezel over the stone will work-harden
the metal and make it harder to bend as you go, and crack more
easily, specially if you are cautious and do a lot of rubbing with
little bending. A rocking tool will do the bending without any
rubbing, so that may be a solution. The burnisher can be used as a
final finishing step.

Fine silver is easier to bend and work hardens more slowly than
sterling silver, so fine silver is a good choice.

The split at the join in the bezel can be caused by two things -
using a butt-joint, and thinning the bezel at the join when cleaning
it up. Use a scarfe joint; that is, file each end of the bezel strip
at an angle so that they overlap and the seam is a shallow angle
across the thickness of the bezel. A scarfe joint will generally be
thicker at the joint, so cleaning up will leave the joint the same
thickness as the rest of the bezel; and scarfe joints no NOT split
when setting the stone! The bezel will be a bit stiffer to bend at
the scarfe joint because the solder in the seam adds a less malleable
layer in that area. A close-fitting joint means less solder is
needed, and therefore less difference when bending the bezel over at
the scarfe joint.

The problem with butt-joints is I only find out at the very end if
they will hold or not. The little extra time to make a scarfe joint
is repaid in peace of mind knowing that I will never have to unset
the stone and go back and make a new bezel because of a split seam.
Hope this helps.

Cheers, Alastair


#3

Kim,

As a relative beginner, cabochon setting was one of the first things
we learned how to do. I’ll tell you how I was taught, which is
clearly a bit different to others. I fabricate my collets out of
0.5mm sterling silver by cutting an appropriate strip, bending it up
and soldering the join. I then attach it to the baseplate of
whatever I’m making. Next, I cut down the height so that the top sits
just at the point where the cabochon starts to curve inwards at the
top of the stone. Once I’ve got a nice even top and it’s the right
height, I take my 3 square needle file (the triangular one,
obviously) and thin the top by filing at an angle, going down far
enough on the collet to encompass the depth that you will be pushing
over (for me, this is usually about 1/3, but it depends on how tall
you stone is). I file away about 90 percent of the metal at the top,
in fact, it almost looks like it’s already set when you sit the stone
in because you end up with a nice bending over effect at the top of
the collet. The top should be almost razor sharp on your finger, if
you press down on it, this is how you know you’ve taken enough off. I
don’t burnish, I put the piece onto setters’ wax and use a pusher to
carefully push the metal over that extra bit to hold the stone in
place (using the 4 quadrants method). This method works really well,
although obviously you need to be careful when pushing over the metal
that you don’t slop. Sometimes I used a curved burnisher afterwards
to get rid of any marks on the metal from the pusher. Happy setting!

Robin.


#4

Kim, In the end you will find the system that works for you, your
own manner of tool manipulation. You’ll get there, that recent ruby
ring you did looked pretty darned fine.

But as to tearing, and this is just my own take on it,.010" is
pretty thin. You have no margin for correction. If you don’t get it
the first time, further stress (pushing, burnishing whatever) will
often cause failure of the metal. Also, when you try to polish out
irregularities in the surface you’re just going to make it even
thinner. I might suggest something more like.020" and if/when you can
manage it, get a hammer handpiece. I find sterling has more of what I
like in a bezel, that is… moderate resistance. I’d rather hammer
more, in little bites. If the bezel is too stiff, you can undercut
the inside to give the metal a place to fold.

Bezel too big? For years i would make bezels a ‘push-in’ fit. In
fact, what this does is hold the stone further below on the bezel
wall, and you’d be folding the metal over the bearing surface. This
is not good(again, just my own take on it, other styles will
disagree). You can tell this kind of bezel because the walls are
essentially vertical and flat. So then you are pinching the stone at
the girdle AND the top, increasing the chance of damage or visible
gaps between stone and bezel If the bezel is purposely made too
large, you can bring the top edge toward the stone, evenly ofcourse,
and the top edge will do the holding. What you’d have to watch out
for is tool marks on the stone. A thick bezel lets you correct
irregularities.


#5

Kim, Not seeing the actual tear, I may be wrong in my evaluation of
the problem. However, it is most likely that the soldered seam did
not hold.

Sometimes, the seam does not get soldered all the way, and there is
a min ute opening which gives way when the bezel is being burnished
over the stone. Check your soldered seams carefully using your
optivisor to magnify them before soldering them to the base plate.
This way you can be sure that t he bezel is soldered all the way.

Alma


#6

Now I could be wrong I was taught to use the hammer and bezel pusher
to tap around the setting in opposite areas ie first tap top left
next tap bottom right and so on the burnisher is a final step to
smooth the finish not to push the bezel that much farther. The stone
should never rattle use plastic cut from a margine container lid or
something equivalent to lift stones or to even out the setting to
make it tight. the stone should fit tight in the bezel before you
even think of the final setting process

Teri
Silver & Cameo Heritage Jewelry
www.corneliusspick.com


#7

Kim,

From what you described, the bezel began to fail at the top of the
join where the two bezel ends meet....correct? This as opposed to
breaking somewhere along the bezel. Were there any sharp corners or
turns along the bezel line? 

To answer your questions: the bezel may have been too big for the
stone. The stone should not ‘rattle’ in the bezel though the bezel
should not be too tight either. There may be just a very slight
(1/4mm approx) space all around the stone to provide relief but I
prefer a closer fit than that. The bezel was probably not too thin. I
prefer either 26 or even 28 ga bezel but the.010 (30 ga) is ok too.
Definately you should use fine silver to start. Sterling can be
difficult to roll down. Height of the bezel could have an impact on
what happened. It should only be high enough to hold the stone
securely. Anything else is not needed and might cause problems.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry!


#8

Kim,

I would have used a thicker bezel strip for a stone of that size.
You were using 30 gauge; I think I would have used 24 gauge (.020").
As a general rule, a larger stone will require somewhat thicker
material.

Many people learning to set bezels will leave the bezel too high. It
seems like a good idea at the time, but once you start pushing the
metal over the stone, you will find it much more difficult to get a
nice looking bezel than if you had shortened it up. It needs to be
tall enough to hold securely, and no taller. A bezel that is too
tall will usually buckle or wrinkle, and it is almost impossible to
straighten that situation out completely. In some instances the
hight of the bezel will need to be varied to follow the contour of
the stone. lastly, I polish the top edge of the bezel before setting,
for that “perfect bezel” you strive for.

If the stone rattled around in the bezel, it wasn’t an ideal
situation. The better the fit before pushing the metal over the
stone, the easier the setting will go, and generally the nicer it
will look. A slightly too big bezel can be overcome, but, again, it
is not ideal.

David Lee, CMBJ


#9

Kim

  1. Maybe, some motion may occur at the beginning of setting. When I
    set mine, if the bezel came out to where the stone moves I may put a
    little E6000 under it, usually I have the other problem, the need to
    roll the bezel a little to get the stone to fit. The stone should not
    move/rattle/shift when set.

  2. I prefer a thicker bezel material, I was never good at getting
    the thin ones to play right, to heavy handed. Sometimes I will make
    my bezel from wire that has been rolled, or plate that I cut. To get
    the thin stuff to work for me, I have to work lightly or I cause it
    to stretch. I can’t let the bezel get much higher than the top of the
    lowest curve or it will pucker from trying to compress to much metal.
    When you look at a cab the profile of the edge should have an angel
    like this ‘/’, this is way to angled but the best I can do with a
    keyboard. Anyhow, you don’t want it to go into the dome area, or in
    your case crystal area, but right to the lip below the crystal
    points. I have seen where people have folded it over the outer edge
    of the crystals, but I am not partial to the look.

  3. Depends on what you like, fine is easier to bend, sterling will
    provide a more durable curl once you get it, both will
    burnish/polish nicely.


#10

Kim,

From your description, it seems like combination of several issues.

  1. Make sure that stone is fits perfectly. That is important.

  2. When you solder bezel, two sides must also fit perfect since the
    joint would be subjected to the great strain during the setting.

  3. The height of the bezel above the stone depends on the thickness
    of the material and frankly on the strength of the setter. The
    smaller the height, the less margin for error and the more strength
    it would require. Ideally it should be as small as possible, but
    everyone should use whatever the individual comfort level is.

Leonid Surpin


#11

Kim:

Bezels can be a lot trickier than most people realize. First, I
always use pure silver, as it will NOT work harden, as some one else
indicated. It will always remain soft and workable despite the amount
of work you put into it. Second, always solder your bezel joint
together using a HARD solder, not medium or easy, and make sure the
solder flows completely! The suggestion that you use a different
joint rather than a butt joint is also a good one, but I rarely have
a butt joint fail when using hard solder.

It is very important to make the FIT of the bezel snug. I always fit
the flat bezel wire around whatever I’m setting and solder together,
then try the fit. If it’s loose at all, remove a short (approx 1mm)
section and solder together again, then try the fit again. Repeat
until it fits very snugly but not too tight! A little adjustment in
this area can be made by gently tapping the bezel wire on a mandrel
(to stretch up a little).

After soldering to the base plate (and when completed and ready for
setting), start by SEATING the stone carefully; if it does not seat
level or otherwise properly, adjust seat until the stone sits flat in
the seat. Start by rolling or pushing the bezel in from the sides,
not at an angle, so that the bezel is flush up against the sides of
the stone (a bezel roller is great for this step). After this step,
roll or push the bezel at an angle so that the upper edge comes into
contact with the stone. To insure tightness, follow with a burnisher
along the uppermost edge of the bezel with pressure straight down on
the edge.

Chris van Laer
ASTERISM Services


#12

Hi Everybody

Thanks so much for all the …I have collected about 5
things I can try! The points about the butt joint becoming too thin
were especially helpful. With the way I was joining the seam, there
was a little ridge on the outside that had to be sanded off. This
made the area near the solder line very thin. Not only that, there
was a corresponding ridge on the inside, which made it difficult to
have the stone sit properly. I can use thicker bezel material and use
a file to thin out the top edge (as suggested) as well. The burnisher
is not the correct tool for me too. I am also heavy handed. When I
was beading, I used to laugh it off and say “I have a lot of
tension”…(get it, being tense and tension on the thread…guess you
had to be there)

Thanks, I will try some things out. I’ve taken the druzy out and
will start again. I’ll report back

Best,
Kim

p.s. Thanks for all the help with the website. It’s up! One small
step…

Kim Starbard
http://www.kimstarbarddesigns.com


#13
I always use pure silver, as it will NOT work harden, as some one
else indicated. It will always remain soft and workable despite the
amount of work you put into it. 

Um, no, not true. It starts out very soft, which helps keep it
workable longer, but it work hardens just like anything else. (Side
note: I’m told pewter gets softer as you work it, but that is the
only exception I’ve heard of.)

Noel