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Platinum solder blues


#1

I’ve just spent the better part of a week fabricating a single stone
platinum 950 ring. I had welded where I could but there were
multiple solderings around the setting.

All was going well until I was setting the stone. I noticed the
solder seam on one of the claws was breaking away.The claw ( one of
4) was heavy and although there had been a fair amount of force
needed to move it down onto the stone, not enough I would have
thought, to break the seam .

I removed the stone and because I had been filing and using steel
punches I put the piece in diluted nitric before starting the solder
repair.

After removing the ring from the nitric I could see all the seams
were etched, some of them seriously…no doubt the cause of
the first seam failing.My heart sank…I had spent hours
on this job…

The nitric was the same batch I’ve been using for months with no
problems I’m aware of.

I had used Platinum easy solder sourced through Cooksons in the
UK…and now I wonder how much platinum was actually in the
solder.

The platinum in the ring is unscathed with no sign of any
deterioration…but the seams are history.I am going to need to
dismantle my weeks work and redo it.

What should I have been using? I’ve heard others on the forum talk
of plumb solders but I can’t get them here in NZ. I obviously was
wrong in using the nitric pickle at the point I did, but after
having iron contamination issues in the past I have tended to err on
what I thought was the safe side by making sure there was no ferrous
content on the metal surface before heating.

I’d be grateful for any advice on how to do this better.

Colin Forster. Queenstown NZ.


#2

Hi Colin,

I've heard others on the forum talk of plumb solders but I can't
get them here in NZ.

Most platinum solders contain far less than 95 or 90 percent
platinum.

The plumb platinum solder you refer to is from PMWest, my employer in
the USA. Contact me off line (@Daniel_Ballard1) to see
how we can ship solder to you. I can only hope the tax or import fees
will be reasonable. I can send a small bit as a sample but you need a
long term source for anything you depend on.


#3

dear Colin

here in the states most of (95%) the platin solders are made of
Paladium and other metals,there is no platinum in them that’s how the
temprauture is lower,you might have to go to hard or extra hard
solders for them to have platinum in them.which might just put you
back in a welding position. I just did a platinum job where all the
seems kept cracking by air exposure, so I have had to call the
refiners about all that.found out it is not even okay to mix
different alloys in a peice,say a 10%irridium platin ,shank welded to
950 ruthinuim top, once it is contaminated ,I have had to cut those
areas and then some complitly out.redo. what was the Gas /oxygen you
were useing for your torch?

good luck
Hratch
Atelier Babikian
www.Hratchbabikian.com


#4

That’s quite a story (and just how is life down under these days?
Hello from stormy California!) In my mind, your first mistake was
using 950 platinum - it’s nothing but trouble. If one is fabricating
platinum, I see no benefit whatsoever in using anything but
10%Iridium - 100 years, give or take, of industry experience with it
counts for something, I think. I can’ t offhand tell you the metal
content of all platinum solders, but in general the high temp.
solders are platinum based - 1700 welding is actually pure platinum

  • 10% iridium RAISES the melting point so pure Pt is less. 1200
    solder (Cobb) has no platinum, it’s a gold based solder. And low
    temperature solders do not bond so well with Pt - even though
    low-flow Pt. solder does pretty well. When you solder gold to Pt
    with gold solder is the problem. My thoughts about your problem? I
    wondered what you were doing with nitric, until you talked about
    iron. Nitric acid does not dissolve steel - in fact it is tranported
    in stainless steel tanks. HCL is the solvent for iron - muriatic acid
    from the hardware store works fine. What nitric will do is leach
    copper and silver out of your solder if left too long. Plus,
    although iron is death for Pt, any infinitessimal amount that comes
    off your tools isn’t going to be a factor. Sounds to me like you may
    not have had enough solder to hold, but, the bottom line is maybe
    you overheated it. That’s easy to do with platinum - you want to get
    it to flow, just like any metal, and then stop. Overheating
    vaporizes, crystallizes, and generally trashes solder and it will do
    just what you say. The solution is just to resolder it - put fresh
    solder on the seams and just reflow it. Unless there are other
    issues (Nitric Acid), the solder should just chase the old solder
    and refresh the seam.

#5
I had used Platinum easy solder sourced through Cooksons in the
UK......and now I wonder how much platinum was actually in the
solder. 

Traditional platinum solders such as you were using contain little,
if any, platinum. An easy grade will be mostly palladium and silver,
plus perhaps other metals. If there’s enough silver there, it will
etch, as you found. Also, the lower the melting point, the weaker the
joint. An easy platinum solder like that penetrates the platinum very
little. I like to think of it as a solder seam with about the same
structure as lead solder on gold, ie different metals wetting the
surface but not really penetrating or alloying with the native
metal. I’ve found I can solder a platinum wire down to platinum sheet
with, say, 1100 solder, and grab a protruding end of that wire with
round nose pliers and twisting the wire around the plier jaw, just
peel it off again like opening a sardine can. Might as well be just
glue, for all the better it holds. (yeah, I’m exaggerating a bit, but
it illustrates that these easier grades of solder should be reserved
for repair work only, in most cases, or places where durability is
not an issue.) Use the highest melting grade of solder you can manage.
I wouldn’t recommend using anything less than a 1300 solder for any
new construction, and most times you’ll be better off with a 1500 or
1600 grade, even for fairly delicate constructions. The 1300 grade,
by the way, still won’t have much platinum, and only marginally
acceptable strength. . 1500 has some, but until you get to the
"welding" grades, it’s still mostly palladium based alloys. And as
with much other jewelry making, the fit of the parts and seams has a
lot to do with strength. If the solder is filling big gaps with more
solder, it won’t look as good, and also won’t be as strong.

The plumb solders are vastly different. The “easy” grade is just as
strong as the harder grades. They can be slightly more brittle, but
not so much as to allow your pieces to come apart. Differences are in
color, melting point, and how easily it flows (the easy is more
sludgy and slower flowing, it seems, but nevertheless melts a bit
lower). All seem stronger than any of the “traditional” platinum
solders, in my experience. They ARE slightly more difficult to use
cleanly, as they don’t flow out quite as well. You get fine solder
flow, but the solder tends to leave a visible scar where you placed
the chip.

The stuff comes from “Precious Metals West”, in California. Find
their web site. No doubt you can order direct from them if you cannot
find a local supplier who carries it. As I said, it’s a little more
difficult to use sometimes, but the results are, with practice, far
superior to what you get with traditional platinum solders.

 I obviously was wrong in using the nitric pickle at the point I
did, but after having iron contamination issues in the past I have
tended to err on what I thought was the safe side by making sure
there was no ferrous content on the metal surface before heating. 

Use, rather than nitric, a hydrochloric acid based pickle. HCL
dissolves ferrous metals just as well as does nitric, but it doesn’t
etch the silver based alloys. And you shouldn’t need to pickle for
more than a few minutes at most. Even a standard sulphuric acid salt
pickle like sparex, if fresh, will remove ferrous contamination,
especially when coupled with an ultrasonic cleaner or steam cleaner
to help with any degreasing.

Hope that helps.
Peter Rowe


#6

Soak your ring in pure ammonia to neutralize the acid first leave it
for an hour to be sure before working on it.

Colin you are using too low a grade of solder and you over heated it
with the blue point of oxygen. You saw little sparks when you
soldered? You should not, just flow it.

First there is no platinum in platinum solder except in 1600 & 1700
and it is very little at that.

1600 degrees solder= .960 grams Palladium and .040 grams platinum.

1700 degrees solder= .850 grams Palladium and .150 grams platinum.

The best for what you need is 1400 solder made with pure gold and
palladium (old palladium findings would be good clean of coarse) you
mix them up 50-50

When you melt this up you must back off your torch very slowly, and
I mean very slowly like 1 mm per second so as not to fill the melt
with air as that will leave you with a metal balloon.

Then roll it down and solder with it, but don’t burn it, just flow
it. And you can flow it over the joints you already have to freshen
them up and you will be okay.

1100 degrees = .900 grams pure gold .100 grams Palladium.

1300 degrees = .800 grams pure gold .200 grams Palladium.

1400 degrees = .500 grams pure gold .500 grams Palladium.

1600 degrees solder= .960 grams Palladium and .040 grams platinum.

1700 degrees solder= .850 grams Palladium and .150 grams platinum.

I never use less than 1400 to do good work. The 1100 is used only to
tack pieces together to do cut out work, and then separate them and
clean off the 1100 to polish and reassemble with 1400 to do a proper
job.

This is good for the David Geller book as well, this is
very handy You can see some very fine platinum pieces
done by me with this at my site.

I am an old platinum expert and I extend this with
confidence.

You don’t need to get all taken up with that plumb stuff sales pitch
that is being touted.

Allan Creates
superringfit.com
P.F.F. Hinged ring Shanks


#7

Thanks to all of you who offered help…I have begun chasing the
plumb solders for future projects. I resoldered using another higher
melting point Palladium based solder as the customer was leaving the
country and needed her ring.

Without the nitric pickling the seams look strong enough but I still
feel that there should have been more disclosure about the content
of the solder when I bought it.

I’ve been using carat grade gold and silver solders for years and I
guess just assumed that Plat solder would be solder of the same or
similar grade to the material I was working with…I think its
a bit rich that the majority of them don’t contain ANY Platinum. How
hard is it to classify or describe the solder as what it really
is?Had I known that 95% of the material I was using would be
vulnerable to acid etching I would have fabricated accordingly.

Thanks again guys…this forum is such a source of wisdom.

Colin. Qtown NZ.


#8
Nitric acid does not dissolve steel - in fact it is tranported in
stainless steel tanks. HCL is the solvent for iron - muriatic acid
from the hardware store works fine. What nitric will do is leach
copper and silver out of your solder if left too long. 

Hi John,

I have to disagree here. Nitric dissolves iron and steel just
wonderfully.I use it to etch iron and steel regularly. Some grades
of stainless steels when properly passivated are quite resistant to
room temperature nitric acid but it is always best to check this out
with the manufacturer of the stainless steel before using it for
storage of HNO3.

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550