Hello out there! There’s a technique that’s been tormenting me for
years & I’ve yet to figure it out; it’s called crystallized gold
inlay. Imagine carving a groove in a wax ring, for instance-
casting the ring in white gold or platinum, and filling the groove
with a high karat yellow or red gold which shows its crystal
formations. The possibilities are endless for beautiful pieces. Is
it an acid treatment after the two metals are fused? Has anyone
successfully achieved this and be kind enough to share this
technique?
The crystal structure is inherent in cast metal and is more evident
to the naked eye when the metal has cooled relatively slowly and is
revealed by the stripping process. In the case of gold alloys, when
used in small shops, this involves a plating rectifier or equivalent
voltage source, some electro stripping solution and a stainless steel
beaker on a hot plate. Acid might also reveal this structure, but
that might be problematic with gold alloys.
If the casting is in platinum, you can, just like solder, flow pure
gold into grooves. Let it cool as slowly as possible, or put it in
an oven at just a bit below the gold’s melting point to set for a half
hour or so, to allow coarse crystal growth. trim off excess gold if
needed (It shrinks a lot when it solidifies, so often there are
shrinkage dips and holes, thus sometimes the need to overfill wider
areas. thin lines don’t need it. But anyway, once the gold is where
you wish it, etch it in cold aqua regia. It works best if the acid
is rather “used”, so not as active, or you can dilute it. Cold and
either dilute or used, it’s effect on the platinum is so slow as to
allow it to retain a bright finish while the gold’s crystal structure
is revealed. Be sure not to mechanically distort the gold, such as
hammering, burnishing, etc. Files and abrasives are fine. But
mechanical working distorts the crystals.
I’ve not tried it, but assume you could also get etching, perhaps
with karat golds, by playing with the acid formulas, but karat golds
tend to solidify with much tighter smaller crystals, so it’s often
less attractive. I’ve also now and then had a similar finish appear
with karat golds when using either cyanide stripping baths, or other
electrostripping baths, especially with 18K and rose golds, and
especially when the baths are not performing quite as they should,
such as too cold, or old and contaminated or the like. sometimes
hard to duplicate just when you wish, but this offers, better than
with aqua regia, the option to get a considerably deeper more
textured finish sometimes. With some 14K casting alloys, I’ve seen
the texture come up with a discernable low relief texture, not just
the visible look. Again, hard to actually get when you actually want
to do so. Usually, it’s been an accident…
Hi, It is best to use the platinum as your base for the inlay
because of it resist to the heat and acid used to acheive this.
I have done this many times and I figured it out through trial and
error before I even knew of orchid.
Make your base in plat. clean and bring it to near final polish.
Make wire of your intended inlay metal ie. 24k yellow, 18k red
what ever they all give different looks and different sizes in
crystal formation. although some of that can be controlled though
annealing. heat the plat. and the wire and puddle the wire into the
channel for your inlays you can use drilled holes. it is best to
undercut these spaces to help hold the inlay mechanically. After
puddling file, sand,and polish careful not to dig out the inlay.
Crystalization of the suface is acheive by treating in aquaregia
an acid mix of nitric and hydrochlorc, check your goldsmiths
handbook the the mix ratio. very nasty and fuming gases very toxic
and dangerous. Plat. is uneffected by this mix soak 2 to 15
minutes to get crystals to visualize and clean with acid
neutralizer. hope this helps, would have saved me months of trial
and error be very careful this dangerous stuff and require proper
saftey tech and equip.
Yes it is a acid etch of the high karat gold crystals. It is
typically done in platinum and 24k gold which is melted/fused into
channels in the platinum with a torch like doing a solder inlay
technique in other metals. After clean up of the fused metal the
item is placed in a kiln at 1400F for several hours to allow the
crystals in the fine gold to grow very large. It is then cooled and
etched with Aqua Regia to expose the crystal surfaces.
It is a very pretty surface but not at all durable so it should
probably be reserved for items other than rings which tend to get
too beat up for the finish to be of any lasting value.
Aqua Regia is very nasty stuff it will burn you severely and rust
every tool in your shop if you don’t store it properly. So if you
don’t have the proper safety equipment and know how to use it and
the proper way to store the acid when not in use you should
definitely not mess with it.
Regards
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau