hello all, I sometimes get a pinkish tint on yellow gold after an
extensive soldering job. (tipping multiple tips ect…) It doesn’t
appear on the outside of the piece. It’s on the underside and in
hard to reach areas. No matter how long I pickle or try to polish
those areas, I’m still not satisfied. Let me say that I have never
had a customer complain, its just something that bothers me. Thanks
for any suggestions.
Bart Tuggle
Bart,
The pinkish color you refer to is most likely the copper alloy.
It is best to use a coating on the work such as Alcohol and boric
acid to protect from firescale. It is also important to stop and
Pickle the piece often if you are doing a lot of work on it.
The lower the karat of the gold the more obvious this problem
becomes if you are heating the piece multiple times without Pickling
and cleaning the piece.
Pickle will only remove the surface oxidation. If you have overheated
the metal and the oxidation goes deep into the metal you will have to
take drastic measures to remove it such as Stripping or Bombing and
even then it may not remove the oxidation if it is extremely deep.
Good Luck
Greg DeMark
email: greg@demarkjewelry.com
Website: www.demarkjewelry.com
Custom Jewelry - Handmade Jewelry - Antique Jewelry
bart,
if I am not mistaken, this is caused by overheating which pulls the
copper out of the gold. try a good firecoat and possibly rather than
continual heating after every so many tips, let cool, pickle and do a
couple more. sometimes too a brass brush on the dremel will help
clean some of this off.
julia potts
julia potts studios
Hi Bart,
In addition to trying to prevent the fire stain from occurring, as
others have noted, there is a way to deal with it after-the-fact by
depletion gilding the piece. This involves heating to about annealing
temperature, until the piece turns an even black, and then quenching
it in pickle to remove the black copper oxide. This procedure leaves
a layer of pure gold on the surface, covering the fire stain below.
The same procedure is used to raise fine silver to the surface of
sterling silver.
If you repeat the process a few times, you’ll build up a thicker
layer of fine gold. This is important because the surface layer
(like plating) can wear off, which makes this an unsuitable procedure
for rings or other items subject to constant friction. I do this
extensively and successfully with earrings, pins and pendants.
Beth
Had a similar problem… BUT was tumbling gold with silver pieces…
All the gold pieces turned silver!!!.. Beautiful, smooth job… Was
a ‘Plating action’… took out the silver… and re-tumbled…
cleaned up in a few minutes… So, my point is… could be a plating
problem that is happening!!!
Jim