Mixing 14k and 21k gold

Question Can you melt 14kt gold and 21kt gold together to use for
making a cast item?

The reason I am asking this is I am in the process of designing a
wedding band for my future daughter inlaw. I have my son’s mothers
band, his grandmothers band and his great grandmothers band, which
are all 14kt gold. He wants to use a small amount of gold from each
of these rings in the new band so his new wife will have part of
each of his grandmothers rings. that is, the gold on her hand will
have been worn for a cumulative total of over 150 years. The
engagement ring has been planned for 18 kt gold. To make the bands
match, I had thought of proportioning the 14kt gold from the old
rings with 21kt gold to come up with a color approaching 18kt gold.
However, someone told me they thought I would have problems doing
this as the metals are dissimilar and would not melt together
properly. Is this true? Do I need to change to 14kt gold for the
engagement ring?

Any help for this student of the arts would be greatly appreciated.

Joe

``````Question Can you melt 14kt gold and 21kt gold together to use for
making a cast item? ...  The engagement ring has been planned for
18 kt gold. To make the bands match, I had thought of proportioning
the 14kt gold from the old rings with 21kt gold to come up with a
color approaching 18kt gold...
``````

That’s very possible. As long as there is nothing in the alloys
except gold silver and copper. Here is my way of making 14k yellow
from various gold karats I have. You could adapt the process (view in
monospaced font):

``````				Au			Ag			Cu
``````

karat wt(g) % wt(g) % wt(g) % wt(g)

22k 13g 92% 12 4% 0.5 4% 0.5
18k 16g 75% 12 12.5% 2 12.5% 2
14k 17g 58.3% 10 approx 21% 3.5 21% 3.5

totals 46g 34 gold 6 silver 6 Cu

to make 14k: 34 gold 12 silver 12 Cu
I need: 0 gold 6g silver 6g Cu

Brian

B r i a n A d a m
e y e g l a s s e s j e w e l l e r y
Auckland NEW ZEALAND

G’day Joe.

The mixing of different Kt types is something I do on a daily basis
for exactly the same historic and sentimental reason as you stated.
If the gold types are the same (Both Yellow or Rose or White
coloured) then the proportions that you calculated should be OK. Now
heres the important part, when you take sections from the rings for
your casting metal, make sure that these sections are free from any
solder, I have found that whenever there has been a problem it has
been associated with casting old metal without the solder removed.
Some solders contain Zinc and Cadmium which at soldering
temperatures is OK but at casting temperature (Including 100 Degrees
F superheat on top of the melting point of the alloy, the zinc and
cadmium vaporises causing that pain in the jewellers life called
porosity).

I’m am not sure from the post wether you are the one that is doing
the casting or someone else, If it is you, use a refining powder
which should be available at most jewellery supply stores before you
cast the metal. If you are not casting the items yourself, then from
my own experience I have found that some commercial casters take
your gold / metal put in the recycling bin and cast with there own
metal. If you find a company that will use your metal then you will
need to supply also the metal for the Sprue and Button. This way,
they do not have to add extra metal which will dilute your original
composition. If you are having it cast commercially then ask for the
casting to be returned with the sprue and button attached.

I hope this is some help best wishes.

PS if you have any further questions please do not hesitate to
contact me of line at either @MWKohlleppel or
investmentcast@aol.com

Michael W Kohlleppel Art Tech Castings Australia @MWKohlleppel

Joe,

This is such a cool idea, that of mixing in a little of the
"marriage logevity gold" into your daughter-in-law to be’s ring!. I
don’t know that much about alloying gold; my experience is only
gradually increasing. Howver, in “dissolving” Cu, Ag, and Au in the
14-16K range, I have come up with an almost hybrid gold, that is
yellow/rosey gold in random mix depending upon the angle of light you
view it in. It’s cool in a way, but personally, I would prefer the
typical 18K yellow that I think you are wanting to get. My opinion,
and I write this wanting too to know with more certainty, is that if
the 21K is close to pure gold in its color, than a small sample of
the 14K rings you wish to use in your new alloy will have a
beautiful color of greater intensity than 18K, unless of course you
use a considerable slice of the the two antique bands, which I hope
you don’t!

I’d like to know how to better achieve a more homogenous
gold-copper-silver mix to attain that pleasant rose gold. Maybe for
me it’s a temperature thing and getting a decent crucible instead of
using a brick to melt the metals on???

Dave Hall, Out-of-Creation Jewelry

Hello Joe

``````   Can you melt 14kt gold and 21kt gold together to use for making
a cast item?
``````

As long as one alloys is not white gold, it should not be a problem.
Due to the 14 K and maybe some solder, you can end up with a rather
harder alloy than usual 18 K. If you only make casting this does not
matter. For a good ductile alloy the addition of gold solder should
be avoided. When I make casted gold object, I use the most shitty
gold rests I have, as long as the gold contend is oke. A bad ductility
is no problem in these cases.

Martin Niemeijer