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Nickel White Gold


#1

I have recently had the most wonderful experience working in nickel
white gold without all the usual horrible problems (!!!), so I
thought I’d pass on my ‘system’…

I often combine silver and gold for the color contrast, so when I
decided to do the same work in all gold, it was important for my
white gold to be as white as possible—thus the nickel gold. I got
terrible staining in spite of my usual fire scale prevention and
found the white gold absolutely horrible to work with, as I need to
solder parts with mirror-finish polishing which can’t be accessed
for repolishing after soldering. When I wrote in to Orchid, Fady
Sawaya suggested a great Italian flux, but I was unable to get a
reply from the supplier, and Martin Niemeijer suggested a product
called Blanca, but the supplier said they couldn’t ship it
(hazardous)…Left to my own devices, I did the following (after
reading all the archive posts on white gold and pickling) and my
white gold came out shiny and unstained after soldering(!):

The main thing is to get a truly COMPLETE coating of boric acid (NOT
borax!!) on the entire surface. My usual boric-acid-in-alcohol was
not strong enough even after several dips and heatings (the alcohol
sort of washes away the boric acid from the previous dippings, so it
doesn’t really increase the coverage). Also, it fails to keep the
entire surface covered under prolonged heating. Since it’s already a
super-saturated solution, the problem was how to get more boric acid
into the act. Mixing the grains with alcochol doesn’t dissolve the
grains—it makes for a grainy paste which doesn’t cover easily.
Then I tried grinding the grains to a powder in a mortar and pestle,
but it still got lumpy when combined with the alcohol. Then I tried
mixing the powdered boric acid with distilled water, and that seemed
to do the trick—it seemed to dissolve better in the water than in
alcohol, giving a more homogeneous solution which painted on quite
nicely. I do several coats with heating in between. The important
thing is to make sure the ENTIRE surface is THROUGHLY coated, and if
there should be any areas where it pulls away when soldering,
REAPPLY! It should melt into a glass surface completely covering
the piece—any place not covered will stain!

After soldering, I quench in ALCOHOL. I use the boric-acid-alcohol
solution to quench simply cause it’s there on the table, and you
know its an OK kind of alcohol. Most of the protective surface
conveniently comes off at this point, but then I boil it in plain
water to remove any remaining boric acid, yellow-ochre/rouge, and
cone borax (my soldering flux). At this point it’s almost comletely
white and shiny. If there’s a bit of slight staining, I soak it in
sulfuric acid and peroxide pickle (see archives), and it comes out
beautifully! All it needs is very light buffing (rouge). So in the
end, white nickel gold is just as pleasant to work in as yellow
gold…

I’d still like a smoother, concentrated solution of boric acid that
paints on evenly. Will try heating the powdered boric acid in water
to see if it dissolves better. Any other suggestions? Any chemists
out there know about dissolving this substance? Even with the water,
it’s a bit lumpy, and I find I have to fill small areas with globs
to insure ongoing coverage all thru soldering. It makes for a VERY
thick coating when it melts. Seems like there should be a way to get
a thin but complete coating. There’s the challenge…!

Janet in Jerusalem