Does anyone cheat when setting center diamond?

Hello everyone,

All right, lets be honest. I need some guidance, and maybe tough

When setting a round or oval center diamond (never pointed ends),
you’ve already cut the seats, tightened the prongs and oops…it
still wiggles a little. You check your seats, but you push, and push
and the diamond will not tighten up. You try various methods of
tightening and then fianlly you suck a little solder in between the
prong and the diamond (19KW) and move on with your day. Diamond is
tight, and undamaged.

Obviously this is not a desirable senario, but has anyone else done
it? Is it really bad or un-ethical? Please shed some light on the
subject for me, as it is important for me to not only be a jeweler,
but a good one aswell.

Thank You.

It’s been done by many I’m sure. Next time after you think the
prongs are down but the stone still jiggles, try moving the 2 prongs
on the same end towards each other very slightly and the the other
end. This will help “wedge” the stone tight also.

You try various methods of tightening and then fianlly you suck a
little solder in between the prong and the diamond (19KW) and move
on with your day. Diamond is tight, and >undamaged. 

I would say that is definitely a bad practice. The good thing is
that you can put it behind you and never ever do it again. I’m
guessing your not cutting the seat as well as you might. You need to
always cut that seat to match the stone. It sounds obvious but most
don’t quite do it. After you’ve pulled your prongs over there really
should be no visible air space between the seat/prong and the
pavilion, girdle or crown. It needs to fit just right.

Many setters never use setting burs, instead they choose to use hart
burs so they can get the angles of the seat to match the stone better
(because they are not locked in to the angles of the setting bur).
They shave and trim each prong individually until the seat fit the
stone just right. If you feel you need to flow solder to tighten it,
I think, you should pull the head and try again.


Obviously this is not a desirable senario, but has anyone else
done it? Is it really bad or un-ethical? 

It’s been said that jewelry making amounts to a relatively small
number of basic techniques, plus a gazillion tricks. The bottom line
might be simply that however you arrive at the right end result is
OK. But the methods you use need to also consider safety of the stone
or item as you work, and the long term durability and servicability
of the piece. Secondary considerations are the time and effort and
cost to get the job done.

Using solder under or around a prong to tighten a stone does, if you
you have to do it, present a way to get the job done. But it’s not
the right way. Slower, and sloppier in many cases. And with thermal
expansion and shrinkage, it’s riskier, even with round diamonds.
Then, you’ve also created a situation where some future goldsmith,
needing perhaps to repair or restore a mounting, might then run into
unexpected problems because of the hidden trap you’ve set for them
with that solder. The need to use that solder implies that you’ve
done something else wrong first. An improper or poorly cut seat, or
improperly prepared, raised, or set beads or prongs, etc. It’s a much
better plan to make sure you’re doing the job right the first time,
so you don’t have to “cheat”. But that said, if you’ve got a job
that’s gone awry, you do what you have to do to fix it. Sometimes
that means starting over at least to some degree. Other times, you
can salvage it with a trick of some sort. If the end result is
acceptable, then you’re OK. Just be sure that the decision of
whether the end result is indeed acceptable is based on the proper
standards, not the convenience of you’re then not having to do
something over when indeed you should have.

To your basic question, do any other jewelers do this? Of course,
when we have to. Personally, I’m more likely to alter an improperly
done prong or seat with the laser welder than with solder, but the
"ethics" are the same. It would be better to avoid having to
essentially do a repair on a new piece by getting it right the first

Peter Rowe

then fianlly you suck a little solder in between the prong and the

It is wise and smart and proper to set a diamond properly so it’s
tight by itself, or to learn how to do it if you don’t know. That
said, we call it “Tightening agent…”


Not a good idea for about a zillion reasons. My favourite stone
tightener is about 3mm dia with a 45 vee ground in the end. Lightly
hollow grind that with 156c setting burr break the edges and polish.
Graver handle and you really move claws tight with a rolling/rocking
motion. I don’t like hard steel near stones, I think I probably have
a brass one in the drawers for soft stones. Re-grinding a tool is
usually easier than stone repairs.

Tough love advice is to get the bearings right in the first place.
Cut 100’s for glass stones, no tolerance here. Setting isn’t about
pushing metal around it is about cutting bearings. If you goof up,
patch just the bearing with solder but heating stones gets riskier
and riskier every day.

Demand Designs
Analog/Digital Modelling & Goldsmithing

I don’t see this as “unethical”, but I do see it as a signal to take
a stone setting class from someone who knows what they’re doing. The
devil is in the details (and practice).

No offense intended, but we all have experienced a need to improve
our skills, and, hopefully, to do so forever. Your learning s far has
either been incomplete or improper, perhaps both. The good news is
that it’s correctable.

Wayne Emery

If one doesn’t mind having a bulgy prong under that $5K-50K+up stone
that someone somewhere is bound to put a loupe to and quite possibly
make a comment about it, and maybe never bring you work again…

To my way of thinking, there are two levels to which we must rise.

  1. make your customer happy 2) not allow circumstances that let your
    competition knock you. Meet both of those and I think you’re pretty
    much covered.

Customers oft times bring me ‘abortions’ from area jewelers who
absolutely don’t follow rule two above. In the old days I would make
comments about how poorly done something was. Then I realized, “Hey,
I don’t have to rub it in, they brought ME the job to do correctly,
they KNOW they got ripped”.

So really, it becomes a matter of self interest. Some might call it
pride in craftsmanship, but I like to get to the nitty gritty…
you’ll make more money if you are among the best.

Mistakes and patchwork have a way of coming back at you.

was the diamond well cut or did it have a thick girdle ? -goo


I’ve seen this done before but I won’t mention names. It is always
best for the stone and the setting not to use a torch. 19k White Weld
has a pretty high flow temp. If your not careful when you try to draw
it in the seat, you can actually etch the surface of the diamond.
Then you’ll have to remove it anyway. Adding heat to the brand new
prong also raises ductility issues, annealling it and making it
easier to bend when it on the customer’s finger.

I would take a breather and concentrate on the fit of the stone to
the seat.

19k White Weld has a pretty high flow temp. If your not careful
when you try to draw it in the seat, you can actually etch the
surface of the diamond. 

I think I’d state it a lot more strongly than that. 19K white weld is
MUCH too hot for safe work right at the prong or seat next to a
diamond. There’s a very high risk and probability, at that
temperature, of damage to the stone. Remember that diamond is
carbon. It CAN, if you get it hot enough, and if there’s any oxygen
around, burn. A general rule of thumb would be that you try to avoid
getting the diamond hot enough to actually be glowing at all. The
metal can be, but if the diamond is getting hot enough to glow, back
off quickly. The principal reasons for using 19K white weld are a
match in color and hardness, mostly so that solder seams like sizing
joints don’t end up being visible after polishing, either as a
slightly more polished/depressed line, or just a color difference. If
you’re simply filling in a gap in a seat, there’s no structural
reason why you can’t use an easy solder. The temperature range is
much safer, and the solder is hidden anyway, so color match isn’t an
issue. The main caveats with adding solder to a seat are that if the
work is ever repaired again in the future, that solder can reflow to
the surprise of the goldsmith who didn’t know it was there, and that
in soldering itself, you’re causing the metal to expand as it heats.
It will expand more than the diamond, and if the gap is then filled
with solder, as the whole cools, you can be actually creating
pressure on the stone with the now-solid solder, because it’s now
shrinking more than the diamond does, but it started with the gap
filled with solder. Normally, in retipping work for example, the
metal expands, and the diamond may be slightly loose while the metal
is hot, but as it cools, it goes back to the way it was. Solder
flowed into a seat can mean you’ve inadvertently created a too tight
seat. That can break stones sometimes, especially corners on
marquise, pear, or princess cuts.


Hi Belinda;

Obviously this is not a desirable senario, but has anyone else
done it? 

You seem to have a fairly knowledgeable of bench work, so forgive me
if I dumb down my answer a bit so others with less background can
access the

Sure, I’ve done it, but I’ve never needed to do this with a new
setting. There are two problems with what you’re doing. First, it’s
unlikely that capillary action “adhesion” will draw the solder under
the prong. That’s due to the opposite effect of “cohesion” that
occurs as the solder doesn’t want to “wet” against the diamond. What
usually happens is the solder flows along the sides of the prong tip,
which tightens the diamond slightly as cooling shrinks the metal down
slightly. The other issue is your use of 19 white weld. (It is
"weld", isn’t it?) That stuff melts at a high enough temperature that
you’re risking frosting the diamond (actually burning the surface),
inviting the need to have the stone re-cut. I’ve used 19 for
re-tipping when I’ve needed to for various reasons, but you have to
be a good observer and able to get in and out with the torch quickly.

What you might want to look at is how you’re cutting the prongs.
Where is the prong making the first contact with the stone? Is it at
the girdle? If you don’t have clearance there, that will make it very
difficult to lever the end of the prong down onto the star facet. You
have to be able to bend the metal downward onto the facet. If you are
only moving the prong in from the outside diameter of the head,
there’s enough memory in the metal to cause it to spring back a bit.
I often us a special set of setting pliers with a slight tooth on the
outermost edge of one jaw which actually bites into the metal and
pulls the end of the prong over the top of the stone towards the
opposite prong.

I’d suggest you get a copy of Robert Wooding’s book,“The Diamond
Setting Manual” and look at page 10 in particular. He uses a
technique we call “vector tightening” for a final tighten on the
stone. It’s difficult to explain here without illustrations and
without writing a major volume,and Robert’s book is not expensive and
it’s worth having in your library. You might look at Blaine Lewis’ CD
set on setting if it’s still available.

Best of luck,
David L. Huffman

I've used 19 for re-tipping when I've needed to for various
reasons, but you have to be a good observer 

I’ve used 20KWW for years on diamonds. I tried 19 and just didn’t
like it. I feel I have more control with the 20. With care you can
draw the solder slowly along the prong without it just gushing all
over the place. To me, the 19 tended not to flow as nicely, but
that’s just my experience.

The other thing is that tipping on top of a diamond is going to be
less dangerous than soldering under the stone. On top you can put the
heat exactly where you need it. Underneath you basically have just
one angle of approach. I suppose you ‘could’ try applying heat to the
opposite side of the prong, to draw it thru, but that strikes me as
asking for a frosted diamond. Girdles being more sensitive to

One trick I’ve seen but not had great success with is instead of
addressing the gappy prong, run the thinnest sawblade under the tight
prongs. The limiting factors here are 1) access 2) if your blade
thickness is not exactly what you need to compensate you are out of
luck 3) the stone will get lower.

If I were in the position of the OP, I’d pull the stone and adjust
the seats. Be aware that now the tip has been work hardened so it may
behave a little differently than the first time you set it. This is
one reason I like to start with overly long prongs… if you need to
pull the stone you have something to grab onto. Mucking it up with
tool marks is not pleasant.

Of course the best cure is to not need a cure. Typically I will cut
the seat in stages. After each cut trial fit the stone. Usually you
can see discrepancies before they are glaring and insurmountable.

Sometimes, no matter what you do the stone may rock as you cinch
down the prongs. A wavy girdle might be the culprit, or maybe the
table and girdle are not parallel. You need to examine the stone
before you set it. If its out of whack you need to indicate a single
point on the stone, so that as you individually cut the seats and
trial fit, the stone is always in the same relative position. For
example put a dot of Sharpie ink on one kite facet and always keep
that dot at 12 o’clock. Also indicate the mounting. For example
always keep the karat stamp on the left. What you’re shooting for
here is consistency of alignment between mounting and stone.

If you still have a rocky stone(hehe) and you just can’t get the
seats right, apply pressure always to the highest part of the stone
in little b ites. This way you can nestle that puppy into place. As
you see the stone level out (or even get worse) you can move to the
next highest side of the diamond.