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Pitting in solder joints


#1

Hi everybody, I have two questions. First, why do solder joints get
pitted? I use an acetylene/air torch, Prips flux, and I just used
14kw easy, 14ky easy, and 10ky medium on four different rings and I
saw pitting on the sides of all four rings!

My other question is, my Grandmother took her emerald and diamond
earrings in to a jeweler to have the stones reset in a different
design. The jeweler refused the job due to not having the insurance
to protect himself if the emerald cracked. Then the jeweler offered
to redesign the earrings using the current settings. Here’s where I
get lost…After putting the earrings in a copier (?) the emeralds
showed up yellow (?)(!) The jeweler declared the emeralds fakes. My
Grandmother was very upset as these had been a gift from my
Grandfather many years ago. Any ideas on either or both of my
questions?

Much Obliged…
Cindy Leffler
Leffler Jewelry


#2
    Hi everybody, I have two questions.  First, why do solder
joints get pitted? I use an acetylene/air torch, Prips flux, and I
just used 14kw easy, 14ky easy, and 10ky medium on four different
rings and I saw pitting on the sides of all four rings! 

Make sure that the joints of the items you solder fit very closely
together, then the solder wont pit.

    My other question is, my Grandmother took her emerald and
diamond earrings in to a jeweler to have the stones reset in a
different design.  The jeweler refused the job due to not having
the insurance to protect himself if the emerald cracked. Then the
jeweler offered to redesign the earrings using the current
settings.  Here's where I get lost...After putting the earrings in
a copier (?) the emeralds showed up yellow (?)(!) The jeweler
declared the emeralds fakes.  My Grandmother was very upset as
these had been a gift from my Grandfather many years ago. Any ideas
on either or both of my questions? 

Many (most) emeralds are treated with resins etc. to fill up cracks.
This is and has been for a long time a normal practice. So it could
be that the resin pours out while cleaning it in f.i. an ultrasonic
bath. That may change the color and clarity of the stone a lot.

Funny thing is that the jeweler knows that emerald is very brittle,
but apparently didn’t check for resins.

The above is just one explanation, check with a professional
gemologist and let him test the stone.

AvA


#3
 Here's where I get lost...After putting the earrings in a copier
(?) the emeralds showed up yellow (?)(!) The jeweler declared the
emeralds fakes 

This is hard to follow. The copier turned the stones yellow? or
the copies were yellow.

I was unaware of the color photocopier as gemological instrument.

Get thee to a G.G.

Elaine Luther
Chicago area, Illinois, USA
Certified PMC Instructor
@E_Luther


#4
         First, why do solder joints get pitted? I use an
acetylene/air torch, Prips flux, and I just used 14kw easy, 14ky
easy, and 10ky medium on four different rings and I saw pitting on
the sides of all four rings! 

Make sure the seams are tightly fitted, and clean of dirt, etc.
Though prips flux is an semi-OK soldering flux, and essential on
silver to prevent fire scale, it really isn’t all that good a
soldering flux, especially for gold. You’ll get better solder flow
with fluxes more specifically intended for soldering (prips is a fire
scale preventor, but is relatively “low activity” for a soldering
flux) Try batterns, or similar.

Also, the easier grades of gold solders are easy grades because of
the inclusion of elements like zinc, and sometimes cadmium, to lower
the melting point. These componants are more easily volatilized if
you overheat the solder, which will give you pits. higher melting
grades of solder, though needing more care in use to avoid melting
the parts, give less pitting. Related to this, though it’s often
common practice to place solder by balling it up with a torch, picking
up the molten ball with a solder pick, and using that to place the
solder, this practice has it’s drawbacks. In many cases, you’ve
overheated the solder when you balled it up, and the solder not only
will now not flow quite as well, or as at low a temp, but it’s sure
to give you more pitting. With gold solders, especially easier
grades, you’re best off cutting paillons and placing them on the
seams, so the solder is first melted only when it then can flow into
the seam. Use no more than needed, as excess solder also can
contribute to pitting.

Pits form when dirt or oxides prevents solder flow leaving a pocket
that didn’t fill, or when componants of the solder vaporize, leaving
gas bubbles, or if molten metal is heated to the point, and long
enough, that either gas from the flame, or gas from the atmosphere,
dissolves in the molten metal but then comes out of solution when the
liquid solidifies, again leaving you with bubbles. The first two
reasons are the more common.

Very closely fitted joints, though not preventing the problems that
cause pitting, restrict the size of the gap in which gas bubbles
(pits) can form, thus the pits, if any, in a finely fitted seam, will
be much smaller and less noticable. Also, closely fitted seams
promote the capillary flow of the liquid solder into the seam, so the
seam fills more quickly and more easily, so you’re less likely to
overheat the solder. And the need for less solder to fill a tight
seam also contributes to less pitting, and a much stronger joint
too.

The jeweler refused the job due to not having the insurance to
protect himself if the emerald cracked. 

While it’s common for jewelers insurance to have sufficiently high
deductables so the average consumer’s stone isn’t covered, most
jewelers who’re worried about this, simply ask the customer to assume
the risk, or a part thereof, if they’re not sure of the safety of the
job. But I’d rather have a jeweler who knows his limits, refuse
something he’s not sure of, than to take it and then cause damage due
to overextending his abilities.

Emeralds can be fragile, and a setter needs to take proper care, as
well as having enough experience with these stones to know how to
handle them with reasonable safety.

    jeweler offered to redesign the earrings using the current
settings. 

Huh? why would this be safer? Unless it’s only minor work, chances
are the stones would have to come out to do the work (unless the
jeweler has a laser welder, but even then considerable care is
needed, since lasers can still damage an emerald. While resetting a
stone in an existing setting is a little safer than setting in a new
setting, it’s still almost as risky as setting in a new setting…

Here's where I get lost...After putting the earrings in a copier
(?) the emeralds showed up yellow (?)(!) The jeweler declared the
emeralds fakes. 

Try though I might, I can think of no gemological equipment that
looks like a copier, into which the stones might be put, other than
perhaps some sort of ultraviolet viewing cabinet. The main "fakes"
I can think of that might be detected that way would be some
synthetics that might show a little bit of red glow, not yellow. But
even that isn’t conclusive. “Fakes” is a strong term. I’d guess
they have to be glass to call em that, and glass is easily detected
with much smaller equipment, often just a loupe, or perhaps a
pollariscope, which doesn’t even closely resemble a copier.

Are you sure this guy was trained in gemology? Or perhaps your
grandmother is relating the tale with less than perfect accuracy.

I’d suggest having her take the stones to someone else, making sure
they’re credentialed gemologists (GG, CG, FGA, etc.) to get the real
story. And find a jeweler who’s got more experience in setting
colored stones, too, while you’re at it. A competent jeweler should
be able reset your grandmothers stones, even if only at her risk.
Your grandmother apparently found someone either without adaquate
experience in identifying gems, or perhaps without adaquate ability
to correctly explain their findings. Just saying "they’re fake"
isn’t really a complete explanation. It seems to me that the
likelyhood of the stones being just cheap glass fakes, if the
earrings themselves are otherwise good quality and also set with
diamonds, isn’t so certain, though it’s possible. More likely, if
they’re not fully natural stones, might be synthetics, which still
have value. And in any case, if these are a sentimental memento of
your grandfather, then there’s still no real reason why the stones,
even if just glass, couldn’t be properly reset into something your
grandmother will enjoy wearing.

Many (most) emeralds are treated with resins etc. to fill up
cracks. This is and has been for a long time a normal practice. So
it could be that the resin pours out while cleaning it in f.i. an
ultrasonic bath. That may change the color and clarity of the
stone a lot. Funny thing is that the jeweler knows that emerald is
very brittle, but apparently didn't check for resins. 

While emeralds have been historically “oiled”, or filled with
resins, actually detecting these treatments is sometimes not a
trivial task. Sometimes it shows up, but other times testing for it
conclusively is not just a quick check. Many jewelers don’t actually
check for oiling or filling on most commercial grade customer’s
stones, since the vast majority of emeralds are treated. Instead, the
stones are simply assumed to have been so treated, and should always
be handled on the basis of that ssumption. The filling materials
are usually reasonably stable these days, and in most cases, don’t
"pour" out of a stone. Stones treated in recent years with actual
resins, usually aren’t so prone to having them be removed with a quick
normal cleaning in an ultrasonic. Some of the older, more highly
liquid, oils that have and sometimes still are, used, can be
compromised. One doesn’t have to remove much from surface fractures
for the stone to then look a good deal worse. Usually it’s just the
clarity that’s affected, unless the “oil” was actually dyed, which
is fortunately, not so common, and is considered unethical. In any
case, cleaning any emerald should be done with considerable care.
Even untreated emeralds can occasionally be damaged by the energy
levels in an ultrasonic, or the temperature shock of a steam cleaner.

Peter Rowe


#5

A simple fundamental mistake many self taught jewelers make is to
use easy solders were you should be using a hard solder. Easy solder
is not easier to use. Hard solder is not hard to use. It often makes
a job more difficult as you have found out. Keep you seam really
tight and use the highest flow temperature solder possible. For
14kyg sizing I recommend 14ky hard or 14ky weld. For 14kwg rings use
19kw weld or 20kw weld. This will help dramatically.

Other things to look for. Again, keep you seam really tight. Keep
your flux and flux brush clean. Be sure to use a boric acid and
alcohol dip and a secondary flux such as batterns directly on the
solder joint.

Good luck

John Sholl
Littleton, Colorado


#6

Hello , Pitting in solder joints , the most common reason is
overheating the joint/solder secondly is lack of cleanliness ,
thirdly poor fit of components . About the “emerald” , there is no
insurance available to cover a craftsman against damage created by
his own hands . The story as you relate it indicates that the
jeweler is not skilled or knowlegable enough to take on such
projects . ANY GEM if now intact is resettable , real or not ,
inclusions , damage or whatever , the more fragile the gem the more
skill the jeweler needs . Have Grandmother take her earrings
elsewhere , where her wishes and questions can be answered
competently with respect , that would include proper gem
identification and that is not a generally recognized alternative
use of a copy machine :slight_smile:

Mark Clodius
Clodius&Co. Jewelers


#7

If you are soldering a joint in a ring shank, you can get a really
tight joint all the way across by passing a saw blade through the
joint while there is pressure on the the join. To create a join with
pressure on it, you pass one end of the shank past the other(above or
below ) as if making a band with a smaller diameter. When you realign
them, there will be tension on the joint. This is harder to do on
heavier guages.When you saw through the joint, you should have a
perfect join with no gaps. No gaps no space for pits. Also, avoid
prolonged
heating at excessive temps. Good luck.


#8

Hello Cindy, Pitting in joint wenn soldering occur wenn surface are
not clean enough, and if you are overheating. Low melting alloys are
evaporating and cousing boiling pits.

Greetings,
Martin Niemeijer


#9

I had a problem with pitting caused by my torch(inadequate) but only
when using easy or medium solder. This may be controversial, but I
stopped getting pits in easy and medium solders by stopping using
them when possible. I have to give credit to Don Norris for an
article he wrote about using only hard solders. I haven’t ordered
easy or medium solder since.

Jonathan Brunet
Montreal