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Are palladium cast prongs brittle?


#1

My boss just asked me this question, and I wasn’t sure how to
respond. Are palladium cast prongs brittle? More or less than white
gold? I find that we haven’t been using them long enough to make a
judgment based on breakage or loss. Does anyone have experience to
share?

Thanks
Judy


#2

daniel at PM west is my source for metal questions my
experienceresulting in his advice to change my fuel for torch
casting has been if the pd gets contaminated with carbon during the
melt, carbon binds or attaches some how with the pd then the metal
will be brittle platinum does the same thing as well as the 14kt pd
gold - goo


#3

To answer this i would love to know a few more details like the alloy
your boss is casting or considering using for the prong components-
because in answering this i’m using an old fashioned 4-6 prong
tiffany style component as the imaginary comparisson of the 2 alloys,
but i know the exact composition of each alloy so its all a
generalization…but here goes:

Many commercial palladium white golds only contain about 6-8%Pd plus
Ag, Zn and Cu… Some may even contain some nickel [so a palladium
white gold is not necessarily nickel-free]. These may also have less
than a good white colour and so may also have to be rhodium plated
to get a decent hardness that will withstand wear…anyway i digress (
as is usual)…

Pd white golds tend to be softer and more ductile compared to nickel
whites and so will not wear as well and due to higher temp.
requirements for processing and are by nature more brittle and crack
more readily than nickel whites. They are available in all karatages
up to 21 karat.( It is not possible to have a 22 kt white gold.) for
example additions of about 10 -12% Pd to Au impart a good white
colour but the impact of density is such that- (palladium white golds
are denser ) the jewelry will be heavier because of it containing
more gold.But the addition of manganeese in the alloying process can
perhaps, bring the tensile strength of the two closer and in terms
of breakage my money would be on a manganese containing white
palladium gold being as hard, to a slight %age less hard than a
traditional nickel white available commercially.and therefore less
brittle…or so i think…if you really want to know more about this
write me off orchid. I wrote a paper a few years back about "white"
golds and their strength for the wgc, and i’m betting it floated away
after Katrina or became glued to some other papers, but if i can find
em i can give you exact numbers…but off the quasi-scientific
cuff,yes they are more brittle,for reasons from temperature to alloy
ingrediets to casting temp, and copper inclusion…the more copper the
softer-white gold has more copper than palladium whites…so it would
follow that prongs would be more resilient…unless you’re talking
mega prongs out of heavy gauge wire or some obscure element of design
that 's why i said i really need more details…or you could call
Hoover and Strong and ask for stewart grice…


#4

A good 950 Palladium alloy should not be brittle. However, it is
very easy to contaminate this alloy during casting. Torch melting is
extremely difficult for palladium and in my opinion should be
avoided. Induction melting under a protected environment is the best
way to go. Palladium will heavily oxidize without protection and an
argon blanket is the best method. Vacuum is not necessary. In fact,
with certain alloys the presence of vacuum alone can embrittle.

Look carefully at the alloy you are casting as well. Given how
recent 950 palladium’s use as mainstream jewelry alloy is, there are
a lot of products out there that are not yet optimized. Do some
research on your alloy regarding hardness, recycle ability,
malleability etc.

Good luck!

Teresa Frye
TechForm Advanced Casting Technology