everytime i put my gold piece into the pickle pot there is a fine
copper(?) layer on the gold. how to remedy?
kim holland
Make a 50/50 mix of hot pickle and hydrogen peroxide, dip piece in
and keep an eye on it. It will lift the copper quickly. Rinse well.
Leda
change your pickle and don’t leave the tongs in the pot…ringman
dump your pickle and mix a new batch. Your current one is saturated.
Hope this helps. A.J.
kimberly It sounds more like you are using iron firetongs or other
iron impliment and the colouring you see is not copper but a fine iron
layer. Try changing your pickle and pick up your work from the pickle
with plastic or stainless steel instead of what your currently using.
Regards William Russell_
Copper dissolves in the pickle as copper sulphate. Silver and gold do
not. If any iron touches the pickle the copper in solution gets
deposited on the gold. Jolly useful if you’re going to do any
granulation but otherwise unwanted.
Throw the pickle away. Its contaminated now. Make up a fresh batch,
Always remove any binding wire from the parts you pickle. Only use
plastic or brass/copper tweezers in the liquid.
Hi Kim,
More than likely, there is some metal other than gold or copper in
your pickle pot. What kind of tongs are you using to insert & remove
the item? It should be a plastic, wood or copper tong. Anything else
will cause an electroplating action that plates the item with copper.
Dump the pickle from the pot, clean the pot out thourghly & put in a
new batch of pickle. Then be sure you don’t put any metal other than
copper, gold or silver in the pickle.
Dave
Kimberly,
I am new to both metalsmithing and this forum, so most of the
questions I am not yet able to answer, but I do believe I may be able
to help with this one. My fine teacher, Fredricka Kulicke, has told
me to always use copper tongs to take things in and out of the pickle.
Using steel tweezers causes a chemical reaction, which forms a copper
plating on your piece.
Claire Oelkers in New Jersey, where both the day and the fall colors
are glorious.
Do you coat your piece in Boric before you heat it? Keeping a jar of
alcohol and Boric Acid on your bench, and dipping your metal before
fluxing (light the alcohol and burn it off before fluxing) will
solve the problem. This keeps air away from your piece, and stops
the coppery look, you wont have to polish much. After making that
comment, we will probably now have a long and heated discussion
between the people who just sprinkle the Boric on, and the
’dippers’ like me. karen
everytime i put my gold piece into the pickle pot there is a fine copper(?) layer on the gold. how to remedy?
Sounds like contaminated pickle – change the pickle and make sure
that you don’t use anything that has iron in it – stick with
stainless steel binding wire if you use binding wire, maybe go to
wooden tongs (like you would find in an oriental foodstore) – when
the pickle gets really blue in color, it contains a lot of copper.
Anything with iron in it will cause the copper to flash onto the
surface of what you put in…Yuck !
Laura
lwiesler@att.net
One really nice way to solve this problem, is to use citric acid. We
have been using a solution of citic acid for several months and it
lasts, it does not eat your clothes, it does not get contaminated
with steel. we just keep adding water just as yu would with sparex.
It works great on silver and gold. I can find no difference. except
my aprins have no new holes
Ringdoc
Let me just confirm the process.
Pickle contains acid. It will be sulphuric acid (as the bi-sulphate
in safety pickle) , acetic if you use vinegar, citric if it’s lemon
juice - they all work quite well but sulphuric is the fastest and the
best if the most dangerous.
Silver and gold alloys contain copper which forms a salt with the
acid and this is soluble. So after a very short time your pickle
contains a copper salt. If there’s enough of it you’ll see the pickle
has turned blue!
Any two metals in an acid environment will have a galvanic electrical
current run through them. This is what causes metal ships to corrode
so fast and why they have sacrificial metallic plates put on them.
The current flows from the silver/gold to the copper tongs when you
reach in to pick up you piece and no metal is deposited on the copper.
The acid just eats away a bit of the tongs. If you use an iron tool to
retrieve your piece the current flows the other way, the iron goes
into solution and the copper is thrown out of solution onto the
silver/gold.
The deposit is always of copper onto the noble metal.
If you need a fine deposit of copper onto gold or silver for
granulation - in order to for a eutectic alloy - this is a useful
process. Otherwise its a bloody bother!!
Tony Konrath Gold and Stone www.goldandstone.com
Do you have a good source for citric acid? I have heard it is better
than Sparex simply because it does not corrode everything around it.
Thanks.
K
Where is your source for citric acid? Would like to try this instead
of Sparex. All for safer and more environmental products. You may
send the info to @Kay. Thanks.