Masking pearles for rhodium plating

I posted this once without success so I thought it best to try
again. Any help would be appreciated.

I have completed a fillgree ring set with diamonds, rubies and seed
pearls. The pearls have been set and now I wish to rhodium plate the
entire ring. Has anyone had any success with masking the pearls so
it can be rhodium plated. I usually use nail polish to mask then
acetone to clean but the acetone is going tho ruin the lustre of the
pearls. Any ideas would be most welcome. Many thanks in advance

Christos…

I usually use nail polish to mask then acetone to clean but the
acetone is going tho ruin the lustre of the pearls. 

The acetone shouldn’t harm the pearls.

Chris- I’ve never had a problem with acetone hurting pearls. I often
will soak them overnight to loosen the pearl peg glue to remove the
pearls from metal that I’ll be heating up. Under the heading “Don’t
try this at home kids”… When I was an apprentice I had a boss who
was in such a hurry that he’d have us rhodium plate white rings with
pearls in them. They’d turn white and frosty and then he’d have us
just polish the surface of the pearl with white rouge to make them
pretty again. I’d NEVER try it now, but it did work.

Jo
www.timothywgreen.com

Try melting bees wax then apply it over the pearls, let dry, then
Rhodium the piece. You can then steam it off and the wax blows right
off.

Good luck.
Steve Cowan
www.aristadesigns.net

Has anyone had any success with masking the pearls so it can be
rhodium plated. I usually use nail polish to mask then acetone to
clean but the acetone is going tho ruin the lustre of the pearls. 

Chris, I saw your first post and thought about replying, then never
did. And I figured somebody else probably did. Nail polish and
acetone shouldn’t hurt the pearl, but it’s very risky to do what you
suggest. Even an instant of contact between pearl and plating
solution or even fumes will destroy the pearl - the surface, but
that’s destroyed. I wouldn’t do it, not ever. I would either remove
the pearls or not plate it.

Acetone should not affect the pearls at all.

I assume you’ve bead set the seed pearls? Otherwise, rhod first then
cement the pearls.

How are you going to electroclean this piece with the pearls in
place? Or is this really the problem? Steam will often be enough,
although I’m not fond of the practice.

When I was an apprentice I had a boss who was in such a hurry that
he'd have us rhodium plate white rings with pearls in them. They'd
turn white and frosty and then he'd have us just polish the surface
of the pearl with white rouge to make them pretty again. 

Just so everyone knows - I bailed a guy out who had frosted a big
expensive pearl in rhodium. What he got was a beautifully polished
mother of pearl bead. Pearls are not polished, and if you DO polish
them, they are no longer pearls - not in the true sense of the word.
Pearl luster is not polish, it’s the natural surface. Yes, you can
make them “pretty again”, but they are gone…

They'd turn white and frosty and then he'd have us just polish the
surface of the pearl with white rouge to make them pretty again. if
you DO polish them, they are no longer pearls - not in the true
sense of the word. Pearl luster is not polish, it's the natural
surface. Yes, you can make them "pretty again", but they are
gone... 

Apart from whatever irritant lies in the centre of a pearl, I was
under the impression that pearls were composed of layers and layers
of nacre - the natural substance which gives the pearls their lustre.
Surely if you “polish” the pearl after a disaster such as rhodium
plating the jewellery that contains the pearl, you are merely
removing one or more layers of nacre and exposing an underneath
layer. Why would that make it no longer a pearl?

Helen
UK

Apart from whatever irritant lies in the centre of a pearl, I was
under the impression that pearls were composed of layers and
layers of nacre - the natural substance which gives the pearls
their lustre. Surely if you "polish" the pearl after a disaster such
as rhodium plating the jewellery that contains the pearl, you are
merely removing one or more layers of nacre and exposing an
underneath layer. Why would that make it no longer a pearl? 

It will no longer look like a pearl, it will look like any other
polished bit of shell. The surface of a pearl is not a polished
surface so if you polish it you loose that pearl luster.

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts

360-756-6550

you are merely removing one or more layers of nacre and exposing an
underneath layer. Why would that make it no longer a pearl? 

Yes, Helen, that is a common misconception. The “lustre” of a pearl
is in the natural surface that has a play of light and a unique
appearance. You said it yourself - more layers of nacre. Well,
pearls and mother of pearl are both made of nacre - the very
identical substance. If it were true that pearls were just polished
nacre, we could easily make our own pearls by polishing MOP beads,
but we can’t. Only oysters make pearls, and it’s the unique, natural
surface that the oyster leaves that makes a pearl a pearl. In fact
if you make a mistake and polish part of a pearl by accident, you
can see the difference in the surface easily. An if you look closely
at some really expensive pearls - I mean REALLY expensive, you can
easily see the unique appearance.

There are some rare individuals who do repair damaged pearls (as
from polishing, for one), and what they do is peel them -
painstakingly take off the outer layers of nacre without damaging
the underlying one, giving a fresh surface.

In a nutshell - long ago I polished a pearl, I don’t remember why,
and needed to match it for something. I went to the pearl dealer and
the first thing he said was, “Well, the lustre is GONE…” It was
a MOP bead, at that point. A good eye for pearls is a real art…

Helen- The real answer is of course is…it depends.How good a
pearl it is determined by how many layers of nacre. I’ve lightly
polished many and my sweetie has even peeled one or two. However we
generally work with pretty high end stuff so the pearls we encounter
have lots of nacre. I did start the post with “don’t try this at home
kids.”

Jo Haemer
www.timothywgreen.com

Apart from whatever irritant lies in the centre of a pearl, I was
under the impression that pearls were composed of layers and
layers of nacre - the natural substance which gives the pearls
their lustre. Surely if you "polish" the pearl after a disaster
such as rhodium plating the jewellery that contains the pearl, you
are merely removing one or more layers of nacre and exposing an
underneath layer. Why would that make it no longer a pearl? 

Helen, it’s true that natural pearls start small and grow from that
small iritant. So they have thick layers of the nacre. And you CAN
carefully polish or work the surface of such natural pearls to a
degree. But cultured pearls are different. The core bead is most of
the diameter of the pearl. The nacre layer is usually less than a
millimeter thick, often less than a half millimeter. If you first
damage the surface, then buff it, by the time you’re done, if
there’s nacre left, it will be a good deal thinner. If thin enough,
it sometimes ends up being almost transparent such that the
underlying banded structure of the beads shows through, and the
overall look of the pearl is not as it should be either. Keep in mind
too, that as calcium carbonate, pearls are attacked RAPIDLY by acids
like rhodium plating solution (which is a sulphuric acid based
solution, and a pretty strong one at that.) Even a brief dip in
rhodium will take off a significant thickness of the surface, not
just frost one outer layer. Also, though you can shine it up again,
even if the nacre remains thick enough, the appearance can change a
little. The “orient”, or irridescent overtone colors in good pearls
are an interference effect caused by the closely overlapping
platelets of which the nacre is made. Polishing the surface of the
pearl can give you a slightly different surface structure, and
sometimes the orient isn’t what it originally was.

Now, the original post was regarding seed pearls. Some of those on
the market are tiny cultured pearls, and the nacre layer on those
will simply not survive either an acid dip, or polishing. Others,
however, are tiny natural pearls with significantly thicker nacre. If
these are only slightly damaged, it might be possible with judicious
choice of polishing compounds, to restore the things. As good as new?
Probably not. But almost? quite likely.

Peter

Sometimes removing a pearl before rhodiuming is impossible - like
when the ring sizing has to be done that day, and there’s not enough
time to soak the pearl off.

I’ve successfully rhodium plated rings with pearls in them by using
clear nail polish (colored polish is absorbed by the glue under the
pearl and looks awful). It’s tricky, because you must make sure to
coat it without any missed areas, and the clear is hard to see. That
includes the underside of the pearl, if it’s visible.

Acetone won’t hurt the pearl. I’ve had to soak some pearls for 3
days to loosen tough, fresh glue. No damage to the pearl.

If you missed a spot, or just to buff out a minor scuff on a pearl
from abrasion, polish that is used for plastic watch crystals on a
dedicated buff works fine. Work with a very light touch, like you
would on plastic. It doesn’t take off the nacre, just restores the
finish enough that it looks good. I’ve restored pearls that have
been briefly put in the ultrasonic that way too. They had that
frosty finish, and came through polishing just fine. This won’t work
with deeper scratches, only very shallow damage.

Of course, I wouldn’t try rhodiuming around an ultra expensive
pearl. I’d have to insist on more time to remove the pearl, or turn
the job down.

Lauren

And you CAN carefully polish or work the surface of such natural
pearls to a degree. 

Peter layed out the more technical aspects pretty well, but this is
a pretty important thing to understand for all jewelry makers. The
most important thing to understand is that there are pearls and
there are pearls - for those of us in the real world, anyway.

If you feel the need to gently touch a $20 pearl on a rouge wheel
just to dress it up, and it comes out looking good, then fine. I’ve
done it myself, just a wisp of a buff on an everyday pearl. We were
in Las Vegas and walked by Cartier and there in a case through the
doorway was a strand of pearls I could only describe as ice cream
for the neck - rich, sumptuous, sensual and warm - and probably
3-$500,000 for 20 pearls or so (South sea, of course). If you alter
the surface of a pearl like that in any way it is tantamount to
chipping or cleaving a big emerald. Where a pearl lies in between
those extremes can be anywhere, but $1200 pearls are not uncommon
these days. Since any change to the surface is, practically
speaking, irreversable, it’s best to think of them as the gems they
are to begin with, and just leave them alone. The finer and more
valuable they are, the more it applies. You can’t fool mother
nature, and the pearls you buy are coming from the oyster to cleaning
and sorting to your hands…

Of one thing there is no doubt - dipping pearls into rhodium and
then repolishing them is mother of pearl bead manufacturing.

Sometimes removing a pearl before rhodiuming is impossible - like
when the ring sizing has to be done that day, and there's not
enough time to soak the pearl off. 

Heat the shank of the ring in such a way so that the heat rising up
does not cause any damage to the pearl, heat until the glue smokes
(do not breathe the fumes). Sometimes you have to do it twice if the
first time does not heat up enough to loosen the glue. Always works
for me.

Richard Hart

Hold the pearl in your fingers while heating the shank…if the
pearl’s too hot to hold, you’re overheating…when its hot but
still holdable the glue should be soft enough to gently twist the
pearl off while holding the shank in a pair of self locking tweezers.

Once you’ve done it once…easy…10 secs.

Colin.

Heat the shank of the ring in such a way so that the heat rising
up does not cause any damage to the pearl, heat until the glue
smokes (do not breathe the fumes). Sometimes you have to do it
twice if the first time does not heat up enough to loosen the glue.
Always works for me. 

Yes, I’ve used heat to remove pearls, and it’s risky. I’ve burned a
few. Sometimes there’s a fraction of a second between loosening the
glue and burning the pearl, especially when good epoxy was used or
when it has been freshly glued. But some of the very old glue used
for pearls won’t come off without heating, so I have to do it from
time to time.

But I consider it too risky for most pearl removal. Some lightweight
mountings have a thin bar across the opening with the pearl peg
rising up from it. It’s very hard to get that hot enough to release
the pearl by heating up the shank. Mabe pearls have so much glue
around them, besides the post inside, that they are hard to remove
by heating without burning. Not to mention rings that have other
stones besides the pearl that can’t take heat. But it is useful in
some circumstances.

Lauren

If it were true that pearls were just polished nacre, we could
easily make our own pearls by polishing MOP beads, 

I’d not really thought about it before, but I was going on what the
poster said about his boss making them polish pearls and they seemed
to be saying that it worked. I guess not.

I see what you mean that peeling to reveal a new layer is a
different matter than polishing to reveal an underneath layer.

Helen
UK

Hold the pearl in your fingers while heating the shank.......if
the pearl's too hot to hold, you're overheating..... 

That’s the old-timer’s way of getting pearls off, and often it works
great. Attack is the other way, sometimes.

The late Mr. B. at Baumell Pearls told us the best way, unless it
doesn’t work, that is. (Sometimes nothing works…) Put the piece
in a coffee cup, cover it with water, and microwave it for a few
minutes. Covering it with water removes the “no metal in a microwave”
problem, plus the temperature will never go higher than the bp of
water. Works great - most of the time.

Hi Jo,

However we generally work with pretty high end stuff so the pearls
we encounter have lots of nacre. I did start the post with "don't
try this at home kids." 

It’s not something I’d try. I was just trying to clarify my
knowledge (or lack thereof) on the makeup up of a pearl. I can now
see that peeling will reveal a perfect underneath layer complete with
its lustre, but polishing won’t. I’m trying to soak up as much
knowledge as I can - learning is fun! :wink:

Helen
UK