Soldering red gold next to white gold

Hi there

I usually work in silver and am now trying to make something which
involves different alloys of 18ct gold. Part of the design might
include 18ct white gold findings (a cluster for tubes for later
setting) to be soldered next to an 18ct red gold setting.

Now, the literature says you must always quench red gold to prevent
micro laminations forming, but that you must never quench white gold
as it might crack.

I will be using a hoke with oxy propane, and fire coating with
Prip’s. I plan to use commercially bought solders in the medium to
hard range.

Would quenching in methalated spirits be an acceptable compromise,
or should I just change the design?

CP
Collarsandcuffs.co.uk

Hello,

the question here is which type of white gold are you using?

Nickel based white gold can not be quenched due to de brittle
character of the nickel. Platinum based white gold is a complete
different story. greatings

Now, the literature says you must always quench red gold to
prevent micro laminations forming, but that you must never quench
white gold as it might crack. 

That depends on the particular white gold alloy, as well as the
nature of the piece. Heavy castings are more likely to crack than
thinner sections of rolled or drawn metal. Die struck settings are
unlikely to crack.

That said, a couple points. Don’t quench (any gold alloy) when it’s
still glowing. Let it cool till the red glow just disappears (about
900 F). Many of the 18K white golds will tolerate quenching from that
temp, especially the softer ones with a bit less nickle. Those are
the ones with not so intense white color. These same alloys are also
often the ones used for the commercially cast (such as from stuller)
or die struck mountings, so you’re likely safe quenching them as
described above.

However, 18K rose golds can actually be less tolerant of quenching,
if done improperly. Again, make sure the red glow is just gone (use
reduced light so you can see it. And if the metal is at all thicker,
or cast, then don’t quench in water. Instead, quench in alcohol.
Quickly immerse the whole piece, rather than being timid and slowly
lowering it into th alcohol. Doing it quickly means it won’t ignite
the alcohol. I normally just quench such things in my boric
acid/alcohol cup, since that’s already on my bench, rather than
bothering to get a container of clean alcohol. Works fine.

Because alcohol is more easily turned to a vapor, the hot metal more
quickly forms that thin layer of vapor isolating it from the liquid,
than does water, and it lasts longer before breaking through (when
you hear the quenching sound). The result is a somewhat gentler and
slightly slower quench. That’s enough to keep the metal from
cracking, yet also enough to prevent the embrittlement of the rose
gold.

cheers
Peter Rowe