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Discolored gold


#1

I do a lot of repairs and sometimes run up on a problem of yellow gold
turning reddish at the place where soldered. I use a fire coat, and
Batterns flux at the place I’m working on. I use sparex pickle afterwards
and it removes some but not all of the reddish tint. I can buff it off in
some cases, but not in others because of the detail or lack of access
(prongs, stones, chain, ect…). I don’t believe I’ve ever had a customer
complain about this, but it can be quite an irritation to me because I
don’t know how to correct it and looks unacceptable to me. I have tried
dipping in cyanide without results. I’ve made myself familiar with the
safety precautions of working with cyanide, but I’m not familiar with the
various techniques of using it. I’m looking to the cyanide as a possible
solution to my problem. I would appreciate any help with ways to get
results from using cyanide, or any other ways to remove the tint that’s
making me crazy.

Thanks !!
Rick Barnes
Gainesville, Florida


#2

Rick:

I suspect that your coating solution is a little thin. Try adding more
boric acid powder and see if this helps. I have never had the problem you
describe because I always use it on any textured piece I solder. You need
it to be a little thinner than a paste but not like water. When you light
it and the alachol burns off, you should have a thick white coating of
boric acid which will melt with heat & completely coat the piece. Best of
luck; Steve K.


#3

I use an old jewelry trick of boiling it in sulphuric acid (mix 10 to 1
with water). Caution… Must be mixed 10 parts water to 1 part acid and
all the ventilation one can get. Good idea to make a chemists acid hood or
large box with glass door and vent system and do all your bad air quality
thing in it and the glass protects you if something goes wrong and still
lets you monitor what is going on.This also works well on those areas that
are hard to get to you can not polish and they have gotten a little
discolored from doing a repair, this tend to brighten those areas up just
a little to make them not so noticeable.

JB…


#4

I do a lot of repairs and sometimes run up on a problem of yellow gold
turning reddish at the place where soldered. I’m looking to the
cyanide as a possible solution to my problem. I would appreciate any
help with ways to get results from using cyanide, or any other ways to
remove the tint

G’day Rick; You should try plating-off in your cyanide bath. Connect
the positive side of a battery (around 3-4 volts) to the job, and the
negative side to a bit of stainless steel. Watch carefully. The reddish
colour should disappear in a few seconds or so. You will need to polish
however afterwards Cheers, @John_Burgess2


#5

A gold star to whoever sends a hint to remove the red stain on gold
without using cyanide. I find the thought of using cyanide too scary.
Felicity in sunny West OZ _


#6

I do a lot of repairs and sometimes run up on a problem of yellow
gold turning reddish at the place where soldered. I use a fire coat,
and Batterns flux at the place I’m working on.

hi rick,

fire scale prevention is much easier than fire scale removal. your boric
acid solution maybe old or weak. if you are using acetylene, that seems to
generate more fire scale (i know i’ll hear it from all you acetylene
users) than a cleaner fuel. propane will generate firestain as well, but
one can use an oxygen poor flame to consume oxygen around the joint while
being soldered. actually, it is oxygen binding with the copper when your
alloy reaches a sufficiently high temp. if there is little or no oxygen
coming in contact with the metal, there will be little or no oxidation. if
one solders too long, the firecoat can break down allowing oxy to contact
your metal. not good. also, if one has old pickle with lots of copper salt
in it and if one is dousing hot into the pickle, it can cause coper to
plate out onto the hot part of your piece (where it was just soldered).

depending on how deep the firestain goes, one can remove it by electro
stripping, abrasives, or by ‘bombing’. soaking the piece in cyanide won’t
do much with the firestain, but bombing will if you do it many times. if
one must use this stuff, know what you are doing+ACE- most jewelers have
quit using it, rarely use it, or are not supposed to be using it. a few
years back, some downtown l.a. jewelers we’re feeding our fishes with it
by pouring it along with the heavy metals it contains down the drain.

best regards,

geo fox


#7

Along with my last posting about the red spots (pickle with %15 peroxide)
try to brush lightly with the soft bristles of a new brass brush.

Rael


#8

I do a lot of repairs and sometimes run up on a problem of yellow
gold turning reddish at the place where soldered. I use a fire coat,
and Batterns flux at the place I’m working on.

make a small amount of pickle adding 15% hydrogen peroxide, see if that
hepls.

Rael


#9

A gold star to whoever sends a hint to remove the red stain on gold
without using cyanide. I find the thought of using cyanide too scary.

From me too.
Has anyone ever tried the peroxide/acid bath that removes copper oxides from
soldered brass. I tried it once but was too impatient(deadline) to really
check results so can’t say if it worked or not. Linda in rainy, dank,
dreary Upstate NY