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Fire scale on white gold


#1

What is the solution to removing the reddish firescale from nickle
based white golds? I’ve tried nitric with no success.

Lisa


#2

What is the solution to removing the reddish firescale from nickle
based white golds? I’ve tried nitric with no success.

Peroxide/cyanide bombing will do it, but sometimes needs several
tries. But I’m going to assume you’re likely not equipped to do that
safely.

Sulphuric acid pickles generally work better than nitric based ones
too, in my experience. Using the actual acid works somewhat better
than the acid salt pickles like sparex.

You might try the old trick used to remove copper flash from brass
or pieces pickled in contact with iron, that being mixing some
hydrogen peroxide with good fresh sodium bisulphate or sulphuric acid
pickle. I don’t know if this would work, but suspect it just might.
Cheap enough to try, at any rate.

But the bottom line is that fire scale on nickle white golds is
nasty, and often just abrasives are easiest. And the real solution
is to avoid it in the first place. Be sure the metal is clean before
soldering or heating. Be sure you’ve got an ample coating of boric
acid/alcohol fire coat. And finally, do NOT use the white paste flux
types. For reasons I’ll never understand, although these fluxes
promote solder flow wonderfully, both on white gold and silver (and
other metals), they also seem to almost promote the formation of
that fire scale, perhaps because they seem to burn away and become
depleted/used up a moment or two before you’re quite done soldering.
If you stick with the less active, but more long lasting, Batterns
type flux, or similar “self pickling” formula, you may find that you
simply don’t get that fire stain very often.

Peter


#3
What is the solution to removing the reddish firescale from nickle
based white golds?  I've tried nitric with no success.

Lisa

Try to dip a good coating of boric acid mixed with alcohol (Like skim
milk consistency) and cook it with a small sharp torch flame, Be
careful if there are stones on the piece
, if you have stones on the
piece coat them with a thicker mix like 2% milk and keep the windows
closed, and don’t breath on the hot stones as the breeze is what
burns the stones when they are hot.

Let it cool slowly in the corner of your tray away from any breeze,
cover it with a can lid or cover of some kind to assure no breeze
comes close to be safe, then clean it off in the pickle pot.

That should do it for you.

Allan Creates
superringfit.com
Perfectly Fabulous Fit, Hinged ring Shanks


#4
What is the solution to removing the reddish firescale from nickle
based white golds? 

Hi Lisa,

I’ve had some success using a hydrogen peroxide pickle. Check the
archives for the formula and instructions. You need a small amount of
fresh pickle to act as a starter, added to slightly warm hydrogen
peroxide. Be sure that your piece is well cleaned, and add to the
peroxide pickle. Bubbles will start to form immediately. I agitate
the item slightly to keep the bubbles from accumulating on the
piece, and allow it to work. Check the piece from time to time by
removing it from the pickle, and using a scratch brush to clean the
firescaled area. It may take a number of tries to remove deep
firescale or at least bring it to a point where the firescale can be
remove with some light sanding.

Good luck!
Melissa Veres, Engraver
@M_Veres


#5

It’s funny how much experiences with the same material can vary! I
have used white paste flux-- most often flouride free Dandix-- to
actually scavenge off that nasty brown/purple scale from Devil’s
metal (nickel white gold). A reheating to annealing temp. w/ a good
covering of that flux seems to clean things up.

I have tried the “magic” peroxide/bisulphate pickle to remove the
scale as well and it works half heartedly.

There were a couple of rings that I made where I induced the nickel
fire stain, building it up evenly over a textured surface to give me
a beautiful and durable dark surface. When given lemons…

Take care, Andy