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Yellow gold turned red after soldering


#1

Hi all,

I was working on a jewellery repair last night that is 10K yellow
gold chain and hollow pendant. All three areas where I had to solder
a new jumpring or bail, the gold went from yellow to a rose colour,
which stayed even after pickling. This includes the whole pendant
itself (a horn shape, likely hollow), the chain and the new gold I
repaired it with.

Is there a chance it’s copper-plated, or I shouldn’t solder 10K and
14K gold at the same time (maybe the chain is 10 and the pendant is
14)? Is there something wrong with my flux or torch? I just use the
mini torch with oxy & propane.

Thanks for any suggestions…I need to fix this for my customer!


#2

Hi Lolly,

Probably the 10K gold in question has a high content copper
alloy(over 40%). When you soldered, the copper content formed a film
that coverd the exterior surface. After pickling and polishing the
piece, the copper will spend sooner than the gold thereby reducing
the reddish color and exposing the gold content. However, it is
likely that the pieces where given an 18k or 22K plating to make it
appear yellow. If the color is still different after polishing, the
customary procedure is to gold plate it again.

Rosy


#3

Lolly,

Forgive this response if it is repetative, as I subscribe to the
daily rag-so I dont see any of the current responses.

It sounds like you may have gotten some steel into your pickle. Or
rather,copper dissintegrated from a piece of steel in your pickle.

You can solve this by sanding and polishing for tougher items. For
softer,or hollow, items, you may want to consider electrostripping.
Reverse your rectifier (or the anode and cathode) and place the
items in an electrostipping solution, easily purchased at any major
manufacturer. This will take minute amounts of metal off the surface.
Be carfeul of consistency and pitting. If your seeing just a higher
carat gold color, not a blatent red, you may have “bloomed” your
gold. This is done by placing hot karat gold into pickle. The
highercarat raises to the surface.

Good luck.
kennon young
www.vermontgemlab.com


#4

Hi Lolly (my aunt’s name!),

Is there a chance it's copper-plated... 

Yes, in a way. What you’re seeing is firestain, the same stuff
that’s such a pervading problem when soldering ordinary sterling
silver. And just as with sterling, there are two main ways to get rid
of it: abrade it off or depletion gild it. I do the latter which
involves raising the fine gold content of the alloy to the surface.

What you’ll need to do is heat the entire piece (several times) and
pickle after each heating. The first time you heat it, you’ll see
that the gold areas turn black while the coppery areas do not. With
each successive heating, more and more of the piece will turn black
(or deep brown, which is fine). When the entire piece acquires an
even black/brown appearance when heated, you’re done: the piece
should then be evenly gilded (“plated”) with fine gold (and will look
yellower than the original material did!).

A few tips: Don’t overheat! Use an oxidizing flame (not one with a
tight blue cone). Keep the flame moving over the piece so you don’t
overheat (and unsolder) anything. Fan the flame on and off the piece
occasionally to better see the development of the black oxides. If
you can, try this first with a test piece of the two alloys you’re
using so you can see the differences between them.

Finally, understand that the depletion-gilt, fine gold surface is
not as durable as the original yellow alloy. This technique would be
questionable for a ring which is subject to a lot of friction, for
instance. But I’ve never had a problem with pendants, pins or
earrings.

Beth


#5

I can’t really suggest what or why, but I sure would like to know
what the go is too!

I have about 20’ of 28ga 14K yellow gold wire that after annealing
went into the pickle and came out red/rose coloured. I suspected
copper but my attempt at using sulphuric acid to remove it hasn’t
worked, mind you that acid was old (I used to use it to pickle
sterling years ago, so it might be spent), and I don’t have any new
actual sulphuric acid as I now use sodium bisulphite (Sparex type)
pickle which hasn’t touched this coppery coloured layer at all
either, even after an over night pickling at 80’C.

I’m really keen to find a solution as I have another 20’ of 28ga 14K
yellow that needs annealing, but I don’t want to be left with the
same results again! This is the only time this has happened I do a
fair amount of work with 14K gold (white, yellow and rose) and have
not seen it before and really don’t want to again.

One other thing is I don’t really know the origin/alloy of the metal
in the wire, but both lengths are from the same supplier so I suspect
they would be the same alloy, the alloy works rather well (not very
springy/tough for 14K) and is quite forgiving so I like this alloy
(what ever it is) other than the discolouration which I don’t even
know will repeat, but am erring on the side of rather safe than
sorry, so I’m withholding the torch til I know more.

Cheers, Thomas.
Janstrom Designs.


#6

I’ve had similar problems myself, I find that a mild heating ( not
to cherry red) and a few dunks in muriatic acid ( available at any
good hardware store) and a repolish brings up the yellow colour by
removing the copper from the surface.


#7

I had exactly the same problem with a 9K yellow gold chain that I was
asked to repair. One of the links had broken so I bought some 9K gold
solder and repaired the link. It turned red. My pickle was also
unsuccessful at removing the red colour. In attempting to polish the
chain, more links broke so I resoldered them. All the large links
(figaro chain) seemed weak so I went round the whole chain and
resoldered them - so of course I now had what looked like a red gold
chain rather than a yellow gold chain. I ended up polishing the chain
by hand so as not to break it again. It was very laborious and took
hours, but eventually the red colour calmed down and the chain was
acceptable - it was still slightly rose gold in appearance.

Someone said that you must have got some steel in your pickle. Well
that certainly was not the case with my gold chain problem. No steel
had EVER got anywhere near my pickle - I made sure of that. Beth’s
answer of it being firestain and the cure being to depletion guild it
seems the most plausible answer.

Helen
UK


#8

Hi,

I’m coming to this thread late, so forgive me if you’ve already
thought of this…there’s a little steel spring thingy in all
boltrings, and some other types of fasteners…if this goes into
your pickle with the rest of the chain…there you have your
contaminant…it’s more likely to be firestain though, given that
9ct is only one third gold, there’s a lot of other stuff in there to
cause the staining. P:S: Don’t you hate repairs on chains…figaro
is particularly naff…or those hollow link ones…aaargh.

Steve Holden
www.platayflores.com


#9

If indeed it is the clasp that is contaminating the pickle (this is
especially the case if your pickle solution is warm) a good way
around this is to use a paint brush to apply a liitle bit of pickle
on the chain where you soldered it. It is not really good practice
to dunk the entire chain into the pickle.We each have a small piece
of glass to rest the chain on for this purpose. As we do over 100 a
day this solution is gold.

Cheers and good luck.


#10

Many mass-produced 9ct or 10ct chains are flash plated in pure gold
to ‘improve’ the colour. The aim of flash plating is to get no more
than a few atoms thickness of pure gold onto the surface. When the
item is heated to soldering temperature the plating disappears from
the surface; I think it soaks into the metal, or it simply floats
off on the oxides of the body metal. Either way you are left with
having to re-plate the affected area to return it to the same colour
as the rest of the chain, or heat the whole chain to remove all the
plating so that the chain is all the same colour - the colour of the
body metal.

If the chain has been depletion gilded then the gold layer is much
thicker than flash plating and it should remain after the soldering
process. After all the soldering and pickling is adding another step
of depletion gilding. One thing throws everything out of kilter and
that is polishing! A quick rub of tripoli will cut through most types
of gilding, and rouge will do it less quickly.

Alloys made for depletion gilding must contain a lot of copper
because that is what depletes. The body metal of depletion gilded
items will therefore be rose or pink gold. If you deplete yellow gold
then the surface will be a pale colour because it contains more
silver along with the gold in the depleted layer.

The best way to polish a chain is to use a fine brass brush
lubricated with bicarb of soda. The brass bristles will burnish the
gold layer (if gilded) making it compact and harder, and imparts a
shine that is just short of ‘polished’ as we are accustomed to from
the polishing motor. I use the brass brush on all chains gilded or
not as the finishing process, to clean the chain before and after
plating, and on any filigree/mesh/fragile items. The brush I use is
a brass shoe brush, I wrap the chain around my hand and brush
vigorously in the palm pulling the chain round and round a few times.
The links end up polished all over inside and out, and it is far
safer and probably quicker than using a polishing motor.

Regards, Alastair


#11

Yes you’re right Steve,

There was I thinking and saying “I never get any steel anywhere near
my pickle” when all along the blessed chain in question had the very
same lobster claw type clasp you talk of! Doh, another Homer Simpson
moment I feel. But yes I do think it was more a case of firescale or
firestain or whatever else it is known as.

And yes I do hate doing repairs on chains and won’t be doing any
more thank you very much. I need to learn to say NO but politely of
course.

Helen
UK


#12

It’s a drawback of the self-taught way, Helen, that we have to learn
by our mistakes, rather than someone telling us what to do and what
not to do…and warning us of any pitfalls on the way…we tend to
fall in most of the lurking traps…the upside is we get to do
lots of stuff that the class takers and apprentices never think of
doing (not during "business hours " at least), for fear of
"offending " their mentors’ sensibilities…

I liken the experience to making a little clearing in the wilderness
then gradually clearing more and more of the undergrowth and letting
in more light and warmth…trouble is if you step outside the
clearing, you can get lost…but usually an Orchid guide will help
you!! After 30 years, I’m still hacking at the weeds with my
machete…but I’m not in Grimsargh anymore :wink:

Steve Holden
www.platayflores.com


#13
It's a drawback of the self-taught way, Helen, that we have to
learn by our mistakes, rather than someone telling us what to do
and what not to do..and warning us of any pitfalls on the way...we
tend to fall in most of the lurking traps......the upside is we
get to do lots of stuff that the class takers and apprentices
never think of doing 

My reality as a class taker and apprentice has been quite different.
I have been exposed to possibilities that I never would have
realized on my own. Gratitude was what I felt for what was shared
that
allowed me greater creativity and better techniques than I had
previously known.

Sometimes there is a moment when I experience a realization of my
self imposed limitation that I was not aware of. It is in
realtionship to experiencing another persons perspective toward
something I am familiar with, but a quite different way perceving a
solution to achieving a metalworking goal.

Sometimes seeing how another person approaches producing work is as
exciting as doing metalwork. Sometimes I learn more from seeing how
the other students in a class come up with ways of translating what
was taught that what I learned from the technique that was taught. It
is the application of the technique.

And it is not “have to” if it is a choice, it is simply accepting
responsibility for a choice made. Front end, chose to self teach,
back end, learn by mistakes. Perhaps not efficient. In time or
materials. Been there done that.

Richard Hart


#14

Hi Steve,

It’s nice to hear someone else sticking up for the self taught (with
the help of Orchid) route! I consider myself to be open minded and
as such try to see the advantages to all scenarios and as I’ve said
before, there are advantages to all learning methods and
disadvantages too. It doesn’t really matter how you get there - it’s
the destination that counts.

What John Donivan said about the wire test is a very good test of
whether or not someone has the skills and vision to work as a
goldsmith for his business, or for any other "traditional"
goldsmith’s shop/studio. And yes, my learning is going to have
limitations if I don’t take classes in every technique, but my work
will develop its own path according to those skills I choose to have
a go at and those which I “master”. People are still keen to put work
my way even though I wouldn’t necessarily yet have the vision to make
that gold wire into something wonderful - although when I read John’s
post I was already thinking along the lines of at least hammering and
forging it into some other form.

I love your analogy of the clearing in the wilderness Steve - it
describes the process very aptly. By the way, did you really come
from Grimsargh? Small world - we live in Bamber Bridge a few miles
away and my son’s girlfriend comes from Grimsargh! Hubby wants us to
retire to Spain too so it’s good to know you can still get Orchid
over there for when we uproot.

Helen
just up the road from Grimsargh! UK