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14k and platinum


#1

Hello All, I’m hoping to get some advice mixed metals soldering. I’d
like to know if 14ky and platinum can be soldered end to end.
Picture two rings, one gold and one platinum, same size, width and
thickness. Saw them both in half and then put the gold with the
platinum half to form a ring. Can these two halves be soldered
together? I’ve gone thru the archives and I’ve read some mixed
comments, including one that I suspect may be true. Would gold
solder be able to flow far enough into the platinum to keep the ring
together? Thanks in advance for your help. Don’t know what some of us
would without this collective brain.

Leda


#2
    Hello All, I'm hoping to get some advice mixed metals
soldering. I'd like to know if 14ky and platinum can be soldered end
to end. Picture two rings, one gold and one platinum, same size,
width and thickness. Saw them both in half and then put the gold
with the platinum half to form a ring. Can these two halves be
soldered together? I've gone thru the archives and I've read some
mixed comments, including one that I suspect may be true. Would gold
solder be able to flow far enough into the platinum to keep the
ring together? Thanks in advance for your help. Don't know what some
of us would without this collective brain. 

The simple answer to your question is - no, it won’t. You can solder
the two together, finish it off just like gold, polish it -
beautiful. But if you put it on a mandrel to round it, or size it,
the seam will surely pop. Prongs, too - if you solder platinum prongs
with gold solder, they will just snap off, or try to. The heat at
which platinum gets that “sweat” where solder permaeates it is, like,
double the melting point of 14k. I would suggest making a key in the
platinum half - a dovetail- “North-South” would give you a design
element, “East-West” would be unseen. Then, if you have finesse with
the torch, you can fuse the gold half on, or, more risky, you can wax
the gold part onto the platinum and cast it in place (better if you
don’t vacuum the flask) Platinum is nice that way - If I do an
"inlay" ring - some pattern of gold on a platinum band, I don’t fit
pieces and solder, I just make a gold rod and melt it into the
spaces, and then file it down…


#3

Hello Leda, I hope someone (Peter Rowe) more knowledgable than I
will respond to this query.

Hello All, I'm hoping to get some advice mixed metals soldering.
I'd like to know if 14ky and platinum can be soldered end to end. 

I will say that the two metals will expand at different rates when
heated. That means when you try to solder the joint, one side will
move away from the other! To avoid that, either find someone with a
lazer to do the joints or use a stainless steel hose clamp to hold
the ring together. Good luck with your project,

Judy in Kansas


#4
  Hello Leda, 	I hope someone (Peter Rowe) more knowledgable than
I will respond to this query. Hello All, I'm hoping to get some
advice mixed metals soldering. I'd like to know if 14ky and
platinum can be soldered end to end. 

Judy, (and Leda), you’ve about got it right. The different
expansion rates can make keeping the joints together when you heat
difficult. but in addition, as a solder joint cools, the expansion
rate difference also stresses the joint. In some cases, it can crack
it. usually this will be on joints covering longer distances, and
i’ve had more trouble with this in white gold to platinum joints,
since the white gold solders are more brittle. I’d bet the 'butt"
joints Leda is proposing won’t be a problem with expansion. The main
trouble is what Leda also alluded to. The big difference in melting
points means that while gold solder flows out onto platinum and wets
it nicely, it doesn’t diffuse into or penetrate the platinum surface
very much, so the seam ends up as a sharp demarcation in the metal
between two very different metals. That can be easier to break apart
again than one might like. The use of the hardest gold solders one
can use will help this, but if the bands you are trying to make are
very thin or narrow, you might have some strength problems. Wider
ones should work just fine. I’d guess if you use stock that is at
least 2 mm wide, and 1.5 mm thick, you should be OK. If you’re
worried, angle the seams, so it’s a bit of a lap joint, not a
straight across butt joint. Or file a groove horizontally in the end
of the platinum, file th gold end to a matching wedge that fits
into the groove, and solder it that way (think of the types of joints
one sees in lumber, for an idea on how this works). It increases the
surface area of the solder seam, as well as adding a mechanical joint
to the thing that will considerably increase the strength of the
joint.

Peter


#5

Hello All ,

I have soldered platinum to yellow [and white] golds many many
times, in many different combinations of sizes and shapes of the
metals, including bands as described and have NEVER had any
particular problem with the soldering or of not having the metals
"stick" with the solder . You do NOT have to do anything "special"
in the way of connection or assembly to have a good soldered joint.

Mark Clodius