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Adding Gold to Silver Casting


#1

I want to cast a piece in Argentium 930 silver, clean up the silver
piece, and then make another casting with wax designs added to the
original silver casting, burn out again, and cast again in 14K gold -
the result, silver and gold in same piece.

Or vice versa, gold casting first, add silver parts second casting.

Which is the best way to go - silver first, gold first, or does it
matter?

And any problems doing this with Argentium?


#2

If I understand this correctly, there are two important
considerations that immediately come to mind…

  1. what is going to affix the second cast to the first. Even if you
    have some sort of mechanical interference fit, shrinkage may have a
    big effect on how tight the join is. I doubt the metals themselves
    would stick reliably together by virtue of one being molten at the
    time of contact.

  2. you must provide a sprue to your second wax. I’d be concerned
    about the weight of the first casting pulling itself off the wax
    sprue for the second cast.

If you surmount these problems (and there may be others) you would
really have something there. Good luck with it.


#3

I have not cast gold to silver. but I have cast gold to gold. You
might consider how much sprueing you need to cast separete pieces in
place.

Good luck, Craig


#4

Since the gold melting temp is so much higher than that of the
Argentium Silver, the gold needs to be first. I think that Argentium
Silver will be great for this, since it fuses to other metals so
well.

Cynthia Eid
http://www.cynthiaeid.com


#5

I cast gold on silver many years ago. The silver had fire scale that
was unbelievable. Fire scale forms on the silver at the higher
temperatures of the burnout cycle. If there is a large amount of wax
in the second casting it is possible the burning of the wax will
absorb the oxygen during most of the burnout cycle and prevent it
from forming fire scale. Once the wax is burned out fire scale will
start to form. The longer the silver is held above the temperature
required to form fire scale the heaver the fire scale coating will
be.

The casting should be cast in an oxygen free atmosphere or
electronically stripped (reverse plated) after casting.

The silver design might be cast in Argentium silver. People who are
more familiar with Argentium silver might weigh in on the subject.

The amount of abrasive polishing that will be required to eliminate
the fire scale will do a lot to damage the design.

The design of the silver piece should be such that the gold casting
will be held mechanically by the silver after casting. A tight joint
may still require joining the metals with silver or gold solder.

The sprue to the second wax should be sufficient in strength to hold
the silver casting during investing.

Lee Epperson


#6

I have cast like that.

14ct gold to silver, no problem. 14 gold is a lower melting
temperature. 95% success

18ct gold to silver don’t work good. 18ct has a higher melting
point. Fine silver works ok

Copper to silver or gold, bad. Forms a solution of gunk

Silver to copper, good-ish

18ct, 14ct, copper, to titanium, good

Now to the esoteric.

Silver to 18ct purple gold, very bad. forms a grey alloy, eats the
purple gold to death I was MOST disappointed, but with the aluminium
component, I suppose I should have known. Still, I am thinking if one
took Palladium foil, wrapped it around the purple gold and then cast,
it might work.

Silver around wood, it can be done. I used Red Ivory wood. It was
not neat and I cast the mould at room temperature. I only heated the
flask to 70C to get the wax out… The wood burnt, but not too bad.

Silver around beach glass, (bottle glass) no problem. Just cool down
slowly. I cast at 700C so the glass is soft when the silver hits
it.10% loss of pieces due to cracking. The ones that survive sell
well.

Silver to wafer silicone. Bad, complete disaster.Dang, I loved the
chrome look of silicone.

Silver to zugelite, not successful, but I think I now know how it
can be done. The problem was the the silver contracted and broke
apart. The stone was unburnt. The mold was heated to 200C but was
cast at room temperature.

And lastly, I made a split crucible and I melted copper and silver
in each side simultaneously and then spin cast it. Unfortunately, I
did not get a swirl of copper and silver in the mould as I had hoped
for. Instead, I got a good grade solder. Well, I tried. I think this
is how it might be done on a spin caster. The copper sprue has to be
short. The silver sprue has to be long. That way the copper arrives
first and semi freezes as the silver arrives…I think?

I got the purple gold and wood castings still so if anyone wants a
picture of them, no problem.

Cheers, Hans Meevis
http://www.meevis.com


#7

Hi

I have cast in place, some smaller pieces of precast / finished gold
pieces into a larger silver mount. I did them for design effect and
some experimentation. Like casting stones in place, I just made sure
the smaller pieces were securly attached to the larger wax model, and
that there was adequate investment attachment to the parts, so they
didn’t break away from the mold after burn out. I used a diamante
investment for it’s hardness and accuracy. Be sure to compensate for
the added metal weight in the flask when calculating your metal
requirements for casting. The casting was successful. There was a bit
of an issue with some slight gapping between the parts due to metal
shrinkage, but all I had to do was, with a little clean up, flow
solder into the connection joints. The pieces fit together quite
nicely.

Good Luck

Dave


#8
There was a bit of an issue with some slight gapping between the
parts due to metal shrinkage, but all I had to do was, with a
little clean up, flow solder into the connection joints. The pieces
fit together quite nicely. 

I also have tried this some. I forget the name of the poster, but one
today showed a lot of experience. I not going to say don’t do it - it
works fairly well some of the time. What I get from the replies, and
my own experience, is that it’s often more trouble than it’s worth.
For me it’s easier, and better results, to just cast the two pieces,
prefinish them and solder them together. One of the big problems is
the oxidation and “gunk” that happens when the wax burns out, and the
temperature issues, to the metal part in the flask. Meaning that the
new casting metal is hitting a “dirty” surface and there’s nothing
you can do about it inside the flask. And maybe investment seeping
into the seam. Plus it’s a mechanical join - unless your flask temp.
is 1400 deg or something, there’s no “brazing” type action going on.
It’s a cold joint. Anyway - yes, it can be done, and no, don’t let me
stop you if you want to. I just found there were too many issues, and
too many errors, for what it was worth - for my part, anyway. What I
do use, that’s related, is I’ll get a platinum ring, cut a groove or
pattern into it, and just flow 18kt. metal into it, and then file it
down flush. That works really well. If you have porosity you can just
remelt it.

http://www.donivanandmaggiora.com


#9
What I do use, that's related, is I'll get a platinum ring, cut a
groove or pattern into it, and just flow 18kt. metal into it, and
then file it down flush. That works really well. 

When you do this, is it a mechanical attachment, or does the gold
diffuse into the plat enough to make it truly one piece?

Noel


#10
What I do use, that's related, is I'll get a platinum ring, cut a
groove or pattern into it, and just flow 18kt. metal into it, and
then file it down flush. That works really well. 

When you do this, is it a mechanical attachment, or does the gold
diffuse into the plat enough to make it truly one piece?

Noel


#11
and just flow 18kt. metal into it, and then file it down flush.
That works really well
When you do this, is it a mechanical attachment, or does the gold
diffuse into the plat enough to make it truly one piece? 

Noel - I think that technically it’s a mechanical attachment. The
platinum doesn’t get hot enough to have a eutectic thing happening.
It is essentially one piece, though. When you file it down (you can
leave it proud, too), it looks like inlay - completely seamless,
bonded together. It’s a bi-color thing that you’d have to fit and
solder in gold, but the difference in melting point with plat. makes
it possible.

http://www.donivanandmaggiora.com