Back to Ganoksin | FAQ | Contact

What aloy is it?


#1

I have a ring 18KW to half shank. It is hallmarked �8 750
UIDC�. It is not rhodium plated. The color does not match 18KW hard
solder, it leaves a line. It is more like platinum in color, so I
tried putting in a piece of Platinum. The color matches better but
the gold kept melting before the solder joint was completed. Does
anyone know what kind of White gold this is? Or how I can solve this
problem and get a nice metal match for the half shank and no solder
joints visible? Thanks in advance for any feedback.

John


#2

It sounds like your alloy (from the 750 hallmark) is European-
Palladium based white gold. European standard does not allow nickel
based alloys. Hence the high white color. Hoover and Strong has flat
sheet 18kt Palladium white. They can also provide some tips on how to work.


#3
  ... The color does not match 18KW hard solder, it leaves a line. 

the problem is the solder color more than the metal color. That’s
hard to avoid. 20K white weld will be a little better, but with
almost any white gold solder, the best plan is to get the seams as
closely fitted as possible, use as little solder as possible, and
thus keep the lines as narrow and hard to see as possible. You can
also try burnishing it after prepolishing it, but before rouge.
Sometimes you can blur the distinct line a bit, which will make it
harder to see.

  .. It is more like platinum in color, so I tried putting in a
piece of Platinum. The color matches better but the gold kept
melting before the solder joint was completed. 

Well, if the ring is 18K, trying to match it with platinum will be
doomed to failure simply because, no matter what the color match, the
two metals are so wildly different in hardness, melting point, etc.
Even if the color match was good, a few moments on the polishing
wheel would show you the seam. Plus, you’ll have to use a white
gold solder in any case, (or were you melting the gold from trying to
use platinum solder with white gold? The problem with that should be
obvious, as platinum solders melt higher than gold alloys) And the
bond that white gold solder forms with platinum is not as strong as
the one it forms with white gold, so a sizing seam done like this
would be in danger of cracking rather easily.

Does anyone know what kind of White gold this is?  Or how I can
solve this problem and get a nice metal match for the half shank
and no solder joints visible? 

The very white color you describe is probably one of the
’superwhite" white gold alloys. these are popular with some
manufacturers precisely because they don’t need rhodium, and avoid the
often dingy yellowish color of some white golds. They do it with a
considerably higher percentage of nickel in the alloy, but the cost
is that these alloys tend to be quite a bit harder and more brittle
sometimes, than the more standard ones. I know. We use these in
our own manufactured line, and our diamond and stone setters HATE the
stuff with a passion. The owners remain adamant about liking the
look, so we stay with the stuff. And the color of a well polished
surface is indeed about the same as platinum. Nice and white. The
biggest problem we have with the stuff (aside from keeping the
setters from yelling too much) is that it seems unusually sensitive
to developing porosity in casting. Drives us nuts sometimes.

Matching the color is simple. match the alloy with a similar
superwhite alloy. If you don’t have a source or don’t want to buy
just the small bit you need for this, email me off list, and I’ll
sell you a piece big enough for your half shank if you like. If you
want to get new metal, most refiners sell such. We now use one from
Argen, but have also used one from David H Fell. But the solder seam
is still a problem. The only real solutions are either very close
and careful workmanship to keep it as tight as you can, or resign
yourself to rhodium plating the repair when you’re done, (which is
often a common practice in repairing white gold work for exactly this
reason), or use a laser welder. This latter is how we handle the
problem. The laser can be used either for the whole seam, or it can
be used to 'glaze" over an existing solder seam. In
remelting/welding over the existing solder line, the line pretty
much disappears, so one can use the laser to “fix” a previous, and
showing, solder line, without needing to completely redo the seam.
In a few cases, you may be able to avoid solder altogether, and just
fuse/weld the seam, but be forewarned. 18K white golds can be very
hard to fuse well with a torch… The welds tend to be poor quality,
and break again easily.

hope that helps.
Peter Rowe


#4
  It sounds like your alloy (from the 750 hallmark) is European-
Palladium based white gold. European standard does not allow
nickel based alloys. Hence the high white color. Hoover and Strong
has flat sheet 18kt Palladium white. They can also provide some
tips on how to work. 

Boy. I’d love to find a source for a high white palladium based
white gold. All the palladium white golds I’ve seen have a warm,
almost brownish cast to them. If you’ve got a source for a nickel
free 18K nice white gold, palladium or otherwise, I’d love to know
about it. We’ve gone through a LOT of different 18K white golds
trying to find one we like in all respects. The palladium whites
seem a bit harder to cast, but much nicer to work, being softer and
less cracky. But they’re simply not as white, at least not the ones
we’ve seen.

Peter Rowe


#5

Dumelang all, I have been searching the perfect white gold alloy for
a long time. Twenty five percent palladium gives an alloy that is
grey- and the whiter your diamonds- the more the contrast…Under
some light it’s stunning, and under other light it’s dreadful i.e
neon LED incadesant, etc ( no matter how much you bright cut)

I have experimented with adding copper to the alloy, thinking that
with just a touch of copper, it might warm the grey up slightly… It
does, a bit, but it removes the easiness that a high palladium gold
has to set stones pave.

I’ve messed around with some two and three part alloys, but to date
I have not come up with anything remotely resembling rhodium
plating… … in the sense that the colour matches the colour of a
reasonable diamond…

And I really dislike any plating that hides a weakness of the design
and construction… Anybody got a good alloy?

Cheers, Hans Meevis
www.meevis.com


#6

www.cooksongold.com in the UK do a good range of 18ct white gold,
including wire, tube, sheet, casting grain etc. and some findings. I
use them myself and find them to be excellent.

Pat Waddington


#7

I just used an alloy from United Precious Metal and was very happy
with the color. It was #915, it does have a high nickel content and a
silicon deox a little harder to set stones but worth it for the
bright color. I bought 2 ounces just to try it, I will be placing an
order for more. Their web site is http://www.unitedpmr.com

Woke up to ice this moring in Denver and you had to wake up to warm
sea breezes blowing through your studio, too bad. Go take a walk on
the beach for me.

Good luck
Bill Wismar
http://www.wismargallery.com