Hi to all those who asked about the white gold. Here are the white gold alloy
recipes. You’ll need a fair bit of heat when mixing these metals. Use oxy-acetyline
with all the usual safety precautions - good fume ventilation, protective dark
goggles, non-flammable environment and protection, the appropriate high temperature
silica crucibles, etc. The secret is to have the highest melting point metal
completely molten and liquid in the crucible first, and then carefully add the
second-most highest melting metal in small pieces so that they are completely
dissolved into the first highest melting point metal, and so on…
In other words, put in the palladium first (it melts at 1550C) and get it molten
before adding the fine gold (which melts at 1064C), then add the nickel, then the
copper, then the silver, last of all the zinc which will flash quickly and disappear.
Keep the crucible moving a little so that the gold roils around and heavier elements
don’t settle, then pour as soon as possible after the zinc has gone in. The zinc
seems to serve no other purpose except to ensure a smooth pour, but I’m no
metallurgist, so I could be wrong about that. All I know is what works in practice.
If you just throw all the metals in together cold, then start melting them together,
the lowest melting point metals such as the silver and zinc will quickly melt and
cover the higher melting point metals. Some of these will deceptively surface-melt but
most of the palladium and pure gold and copper will simply form lumps of pure metal.
The metal manufacturers avoid this by using specialised furnaces and crucibles, but if
you are melting these up on the jeweller’s bench, you may not have this sort of
expensive equipment.
(Au = 24ct gold. Pd = Palladium. Ag = Silver. Cu = Copper. Ni = Nickel)
Palladium White Gold Alloys: 18ct White: 75% Au + 10% Pd + 10.5% Ag + 2.5% Cu
- 2% Ni
14ct White: 58.5% Au + 10% Pd + 28.5% Ag + 1.5% Cu + 1% Ni
Nickel White Gold Alloys: 18ct White: 75% Au + 14% Ni + 5.5% Cu + 5.5% Zn (Zinc)
14ct White: 58.5% Au + 14.5% Ni + 20% Cu + 7% Zn or 58.5% Au + 15.3% Ni +
25.8% Cu + 0.4% Zn (Harder alloy) 9ct White: 37.5% Au + 17.5% Ni + 27.6% Cu +
17.4% Zn
Palladium-Nickel White Gold Alloy: 18ct White: 75% Au + 15% Pd + 5% Cu + 5% Ni
It’s interesting to do small batches, but, in all honesty, the refiners and assayers
do it much better and will accept responsibility for their product if it’s not quite
right. Hope this helps, Rex.