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Experience working with 950 palladium


#1

hello all

After months of trial and errors and experimenting, I am asking
anyone on orchid with info and experience in working palladium and
it’s alloys to give me some direction.

I am interested in using the 950 palladium of hoover which is very
nice metal, in wrought goods or the castings from them.

Earlier on I had cast a few pieces in NYC in palladium 950 ; the
metal was about 5 shades darker then hoovers and when i came to
working with them the HS metal stayed bright after annealing with a
slight pink shadow that I took off with a scotch brite pad, now the
NY casting after annealing actually went even darker in patches and
stayed darker I could not get it off with the abrasive wheel. the NY
one is noticeably bluer then the Hoover and strong alloy.and I mean
Blue that is not coming off, and i can’t really abrade it too much
since the pieces have very fine textured surfaces part of the
design.

I called the caster in NY (I don’t want to mention names because
this not what I am writing for. they have been a great casting
company for a very long time). so with the phone call they couldn’t
help.

I know that hoover & Strong’s alloy is right on,i am just wondering
after talking to few experts in town how much of a variable there is
going to be with these alloys. is there the possibility of
contamination of metal,or crucibles or??? in my mind 950 pall is the
same color everywhere.

if it is like platinum 950 or 900 is most of the time the same color
from any where,

my problem is that I was trying to match older cast things for a
client to a new piece or so and the color does not match at all. the
hoover metal almost had a slight pink/warm hue vs the other that is
on the blue/Grey side.

is it possible to mix the palladium with different things and have
it be 950. is this working the same way as the karat Golds, as in 18
is 18 but you have as many choices in color as there are
metallurgists ?

Does this mean that for consistency’s sake to stay with one company
or another??? would palladium 950 have a difference in color then
say united metals or Ross or…??

or is it that the casting houses will be using different
methods/gases/atmosphere of casting and so the same metal comes out
different?

One more thing on the palladium scene, I been using also the karat
golds the 14 and 18 palladium on occasion and noticeably the 18k has
been getting very dark after annealing and soldering, and the sparex
is not taking that dark almost black discoloration off, is that
oxide,‘firescale’ do i need to use a white gold acid or nickle type
acid.

help
sincerely
Hratch


#2

The blue is from a trace amount of cobalt in the alloy. Currently 4
alloys have risen to the top for casting. Johnson Matthey, Hoover
and Strong, David Fell, and United Precious Metals. All 4 alloys have
slightly different formulas and characteristics ranging from
hardness to reusability. These slight formula changes do affect
color. Side by side one can see the color variations making sizing
and duplication cumbersome. Your caster or supplier should give you
the contents of the alloy they are using or the main ingredients so
that the pieces can be matched or sized. Feel free to call for any
more detailed info.

Linus
Au Enterprises


#3

Ok,

First a disclaimer, I haven’t had much contact with Pd950 alloys.

That said I would say that metals supplied from different sources
would have a high probability of being different alloys (even within
the 950 stipulation) and thus different colours.

If you are trying to match pieces I would always recommend using
metals supplied/sourced from the same place. And if possible I would
also use the same caster to do the pour.

As for palladium white gold, I have been using a custom made 16K
palladium white that is almost (when polished fully) indiscernible
from Pt900 (when I say almost, I mean if I don’t let on no-one has
yet picked right, with out picking up the pieces first), and is also
very hard (a real negative for some things like prongs let me tell
you!), I have found that it will develop fire scale that is real hard
to etch off, I have had limited success with hot (almost boiling)
Sparex and long soak times. Mostly though I use 1200 grit 3M film if
it’s towards the end of the assembly process and just remove it.

Thomas.


#4

Hratch,

I tried working with 950 palladium for one year and then gave it up.
I was never truly happy with any of the results I was getting. I
think it is a material that needs a real manufacturer’s type of
working conditions in order to produce satisfactory results. As a
smaller shop I couldn’t get the cleanliness?? or whatever it was
that was necessary to get it to come out as I wanted it to. Went back
to hustling the platinum and 18k palladium white gold instead.

Daniel R. Spirer, G.G.
Daniel R. Spirer Jewelers, LLC
1780 Massachusetts Ave.
Cambridge, MA 02140
www.spirerjewelers.com


#5

Hello Hratch,

After months of trial and errors and experimenting, I am asking
anyone on orchid with info and experience in working palladium and
it's alloys to give me some direction. 

Your questions are very good ones given the number of new 950 Pd
alloys that are being used in the industry. Some companies do
sufficient testing of their products before they market them, and
some leave it to the jewelers or retailers in the field to do it,
often with bad results. As a contract caster, I have tested 8
different 950 Pd alloys and have had very differing results. Most
were bad. I cannot stress enough the importance of having the right
alloy. A 950 Pd alloy that is composed of platinum group metals will
certainly not have the bluish or dark gray colors that you describe
unless it is associated with surface oxidation resulting from
exposure to a torch, and that comes of easily as you describe. I
suspect that the alloy you refer to contains cobalt, and that perhaps
this did not remain homogeneous in the alloy. The casting process
itself can also greatly impact the outcome, as palladium will heavily
oxidize if not cast in a protected environment.

What I can tell you from my experience is the following:

  1. There are very few good 950 Pd alloys on the market, but they DO
    exist. I have been casting a PdRuGa alloy since January with
    fantastic results. The hardness, even with partial recycle has been
    maintained in the range of 125 to 140 Vickers. I test my metal supply
    every six weeks to be sure.

  2. Several alloys on the market are dangerously soft, ranging from
    60 to 100 Vickers. In addition, you also have casters that mix their
    own alloys, but never bother to get a hardness test. So, their only
    criterion is whether it looks good in the as-cast state with no
    concern for after market performance.

  3. The casting process must be a highly controlled one. I have been
    casting platinum, (not exactly the easiest metal to cast) for over 12
    years. Without question, palladium is more difficult to cast than
    platinum.

  4. At the moment, with 950 palladium you need to do your own
    hardness testing on the product you choose at least once. Don’t take
    the sales guy’s word for it on hardness values. For only $78.00 you
    can have a hardness test done at an aerospace certified lab here in
    Oregon. The name of the lab is Koon-Hall-Adrian Metallurgical and
    their website is khametal.com. It is a small price to pay to know
    that your stones won’t fall out and your ring won’t become oval.

950 palladium is a beautiful metal that is wonderful to work with,
but the industry is jumping in with both feet and not everyone is
taking the time to do their homework. It saddens me to see the short
term dollar taking precedence over the long term reputation of 950
Pd. Whether you are a bench jeweler, a retailer, or a consumer, your
first experience with 950 palladium will strongly shape your attitude
toward the metal. I can assure you that it does not have to be a bad
one.

Please feel free to contact me off-line if you would like more

All the best,

Teresa Frye
President
TechForm Advanced Casting Technology
(503)652-5224


#6

In August, I made my first ring entirely from palladium 950. I
needed a cluster head for a 5.5mm pearl and .0075 ct. diamonds and
heads for 2 5.5 mm tapered baguettes. I decided to cast the heads
from waxes that I machined with my CNC system, and fabricate the
shank from 1.5 mm square wire.

I contacted Hoover and Strong about their contract casting in
palladium, and to purchase the solders and shank wire needed for the
project. They suggested that I send them a second wax of the setting
components (the three heads were on a common sprue. They cast the
first wax sucessfully.

The castings came back clean and bright. The fabrication of the ring
went smoothly using medium palladium solder and a platinum post that
served for both the pearl post and located the cluster head on the
shank. I found that it worked easily, and was similar to fabrication
with platinum. The tiny little diamonds (18 of them) set easily, and
securely. I have another palladium ring coming up, setting a radiant
emerald cut diamond with 6mm trillions. I’ll probably fabricate all
three stone settings…

Rick Hamilton