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Burned diamonds

It was one of those days…I was sizing down a 3.5mm platinum
channel set anniversary band with 14 three pointers. Simple huh? I
placed the band upside down (sizing joint up) on clean charcoal. I
set one charcoal on top of another and lean the ring against it
upright so there is no need for tweezers to hold it. I had placed my
piece of platinum 1700 solder in the joint, put on my goggles and
fired it up. FINE & FAST no problem until I saw all 14 stones were
milky and opaque, not bright and shiny like before. Are they
burned??? I dipped in alc/boric solution just to protect the stones.
Was that my mistake? Pickle did not effect them in any way. I have
sized many, many platinum & diamond rings and have never seen this
before. I am stumped and out almost a half carat to boot. If you
know how to save my — please let me know. Love to you all, Patty Rios

Hello Patty; Long answer here.

My guess is that yes, you have indeed overheated the stones.
Problem is, the charcoal block was not a good choice in this case.
Charcoal is carbon and carbon is fuel. You probably didn’t realize
how hot the ring was getting. If this ring was thin, as I suspect
(being set with .03 carat stones) it wouldn’t take much to overheat
it. If it’s an old mounting and was set with single cuts, those are
all the easier to overheat. If you can carefully lift back the
channels, you can re-set the ring with new stones. Here’s what I
would do if I were in your shoes.

First, inform the customer what happened, that things like this do
happen occasionally, and that you will correct the situation to their
satisfaction. You will need to buy a little more time, but prioritize
this. Second, if you can’t peel back the channel to remove the
stones, you will have to grind away one side of the channel and
remove the stones. You can sell them to a company that buys damaged
stones, but I don’t know what you can expect to get for them.
Perhaps someone on Orchid has experience in this area. You could ask
about having them re-polished and if this was cost effective, when
you re-sell the re-cuts, you’ll recoup some of your loss. Remember,
you’ll be buying the new stones wholesale and selling the re-cuts at

Now, carefully fit in a piece of platinum to replace the area of the
channel you’ve ground away. Here’s the most important part. . . .
Lose those old platinum solders! Call P.M. West or one of the other
refiners and order some of the new platinum plumb solders, at least
the hard and easy. They’ll cost around $50/dwt. These melt at
around 1350 C instead of the 1700. You can use your old solders for
some kinds of fabrication, but once you try the new solders, you’ll
never to back to them for sizings. Get a ceramic soldering pad
designed for platinum work, and a titanium solder pick or some
ceramic tipped tweezers. It’s crucial that you not have any gold or
steel in contact with the platinum when you’re soldering. Platinum is
not a particularly good conductor, so it’s sometimes possible to keep
stones protected by keeping them under water when you heat. I often
use wet sand to hold up a ring while soldering (but it’s clean sand,
no metal filings). Use the hard grade of platinum plumb solder to
solder in the new channel wall. You’ll have to have a slight “V” at
the seam since these solders don’t flow as easily as gold solders.
Heat a little at first, then stop and examine the ring to make sure
there is no other solder work in the area. If there is, you’ll be
going to plan “B”, I think. I know you don’t have a laser, or you
probably wouldn’t have been sizing with a torch. After you’ve dressed
up the channel, then re-set new stones. You’ll spend about $250 for
the new stones, maybe less if you have a good source for melle=E9.

If the customer isn’t satisfied, or you don’t like the job when it’s
finished, you may have to order a new mounting, or carve a wax and
cast (or have cast) one to match (plan “B”).

There is no easy way out, but you can use this chance to solidify a
relationship of trust with a customer, and when you do fix this to
their satisfaction, you’ll have bought the best lesson in how to
build trust and confidence in your customers and you’ll look back and
realize it was a bargain. The truth is tough, but it has power.
Good luck, write me if you have any questions.

David L. Huffman

Seems like I have run into this before, it is a coating on the
diamonds. How well were they cleaned before soldering? A suggestion,
I use majic flux on the piece and a drop of batterns at the joint.
the majic helps and is easy to remove. My Suggestion is to hot
pickle the piece, then ultra sound the piece, scrub with a tooth
brush and then steam. there are more aggressive techniques, one being
Drano. Ringman

…are you certain they’re real diamonds? I’m a student, I’ve seen
lots of things go wrong… CZ’s turn milky and opaque, the one
diamond I’ve worked with was cast in place, so I figure it got plenty
hot, and it’s still…well… ugly, but a diamond =) Just a thought…

(why would anyone set a CZ in platinum?)

I had the same thing happen to me a couple of years ago. All the
diamonds in the band turned frosty milky white and all I did was size
it. Test the stones make sure they are real diamonds and not
something else and make sure they were not filled. I never did find
the answer the wholsaler I was working with knew me and just gave me
diamonds to replace the damaged whatever they were. Something not
quite right about the stones… Frank Goss

Patty, It sounds as if you have indeed burned the diamonds. I should
know. I have burned quite a few in the last thirty plus years. To this
day I have been unable to find anyone to repolish mellee either. I
have always been stuck in the position of replacing such stones out of

Years ago, I was assigned the task of melting down a customers
platinum watch to build something else out of. I carved a depression
into a charcoal block to melt the metal into. I put on a filter plate
and started the melt. Unfortunately, I couldn’t really see anything
but the molten metal. I couldn’t see the groove that I was cutting
into the charcoal with my torch. Imagine my surprise when I pulled my
torch away any found the white hot puddle of metal having been
suspended by gas pressure from the torch suddenly released and racing
in my direction! Only incredibly quick thinking is allowing me to
father a child in about nine more weeks. Upon remelting this metal, I
found that it cracked and crumbled when being rolled. We told the
customer that the platinum was no good and would need to be refined. A
couple of years later, I was building a channel setting from sheets
of platinum and found the metal breaking down after soldering. A
couple of years after that experience, I learned something of carbon
contamination in platinum and have not suffered through cracking
platinum since. Carbon is one reason that acetylene is not recommended
for platinum work. My experience has however shown that it is fine as
long as it is used with plenty of oxygen. On the rare occaision that
I have contaminated platinum since, I have been able to remove the
carbon by heating the platinum to a bright red and keeping it there
for a minute or two.

Another thing to avoid is over heating your platinum with flux or
boric acid. It has been noted that one should be particularly careful
with the newer cobalt platinum alloys as these chemicals can migrate
through the lattice and disrupt the workability of these alloys as

Bruce Holmgrain
JA Certified Master Bench Jeweler

    My guess is that yes, you have indeed overheated the stones.
Here's what I  would do if I were in your shoes. 

David: What a really nice and concerned reply you sent to Patty.
It is always gratifying when someone simply acknowledges a problem
right up front, doesn’t skirt around it, and is willing to say what
they would do. I’m not in the repair side of the business at all - I
would probably be hysterical if I were - but it is certainly very
nice to see that others out there are so very understanding and
helpful. If I were Patty, I’d feel a lot better about what happened

  • not great, but sure better than burying your head in the sand and
    trying to pretend it didn’t happen.

I want to say thanks to you for being so supportive and
understanding - not to mention that I learned a lot from your answer.
Thank goodness I’m not a professional having to deal with these
problems. Not sure I could handle it.


They may be treated diamonds , if so,there is a good chance that
Ovid of N.Y. can retreat them for you at little or no cost.

Ralph Cross
Fremont Jewelers

Patty, When you leaned the ring against the other charcoal you may
have created a furnace.If you did not aim your torch flame up and
away from the diamonds but towards the charcoal wall it was leaning
against.It could deflect the heat down to the diamonds.Charcoal is
not a good soldering block for noted by the other posts.When
I size Plat. I watch the heat trans fer down the shank I try not to
let it get red near the stones.I also fuse most sizings.If they are
going down I use the Plat that I have cut out.I lay the piece that
was cut out on the shank and heat aiming my torch up from the inside
first then on every side of the seam until if flows.I also have my
flame set so it is very hot.The faster you can fuse the seam the
least likely you will transfer heat to the stones.If iam sizing up I
use the same type of plat.stock and cut a piece to fit in the ring.I
cut two little pieces to lay on each seam and fuse each side.I do
this with the ring being held in tweezers.Frying diamonds is not a
hard thing to do.When working with platinum I have had my share also.

Regards J Morley

Hi Patti, you may have gone in a little too “fine & fast”. I’ve burnt
a few diamonds over the past 46 years and it has always - for me at
least - been associated with sudden extremes of temperature either in
the heating up or the cooling down. I had one diamond literally
disintegrate when my oxy-gas flame blew out and suddenly bathed the
red hot diamond with cold oxygen. It literally exploded - disappeared
out of the setting! Luckily it was only a .10ct, but I am totally
sympathetic with your experience.

Like you I usually leave smaller diamonds in situ and normally get
away with it 99.99% of the time. Larger diamonds I always unset.

I hope it’s just a silly question, but were they really diamonds?
CZs can go suddenly milky with even lower (non-platinum) soldering

Kind regards, Rex Steele Merten

Thanks, Kay;

I appreciate confirmation that I’m on the right track with this kind
of thinking. Believe it or not, I didn’t come to this approach right
away (chuckle). Having been a jeweler for a long time, I came to the
realization somewhere along the line that being honest and direct and
not rationalizing isn’t just a matter of ethics, it’s a matter of
emotional economy. With a little practice, I’ve developed some
modicum of confidence that mistakes, while immediately threatening,
tend to come into perspective with time. There’s often something to
learn, and one can never underestimate the drain on the psyche of
periodically diving into a panic and searching desperately to avoid
the inevitable. Eventually, I think we come to realize that lost
money and initial embarrassment are easier to recover from than
prolonged guilt. Thanks again.

David L. Huffman