Hi folks, this is my first try on this system. I have a
problem with platinum crowns. I buy them from Stuller. The
prongs seem to be soft and bend side to side too easily. Am I
doing something wrong in soldering or is this a problem with all
or only Stuller’s plat crowns? I have talked to their plat tech,
but have not really gotten an answer. Any help would be nice.
Jeff Kaiser
Jeff, I find lateral stiffness to be a problem with nearly all
platinum prongs of any length. I believe that is why platinum
prongs are usually a little heavier. I try to support them some
how or try to set the stone as low as possible, possibly by
ordering the setting one size larger. Quite often with stuller I
order 2 sizes of heads for the same job and plan on sending one
back. We send a package back to stuller every month for credit.
It works great for me.
Ray
Hi Jeff We also found out that Stuller gives buyers a disclaimers
that make me question the sources of the alloys it uses. I am a
geologist and my husband a phycisist and we thought we had a good
understanding of chemistry. We have never heard of “cosmetics
being harder than jewelty (gold)” If you read in the back of the
small findings book, page 411 . It indicates that “when a ring
turns, blackens or discolors,… the most comon reason is
metallic abrasion caused by makeup on skin or clothing” I have
never found this to be true. I asked them if this would happen
in 10 K gold only, but they said it could happen to all gold. It
may be that the employee was misinformed, but I am
weary…Maybe someone can inform us about this too. Thanks.
Elizabeth
Elizabeth, It is true that cosmetics can cause metallic
abraision. Many cosmetics contain rouges and other compounds
which are abraisive to gold and silver. This abraision comes off
as a black powder - the same as does rouge polishing compounds.It
has nothing to do with the alloy. Ken
Hi Elizabeth, I’ve always heard that when precious metals darken
with skin contact, it is the result of the body oils with the
alloys of the metal. I do know that by rhodium plating the
inside of rings worn by people with this problem, it can be
alleviated. Obviously higher karat golds would have less
problems, right? I certainly haven’t heard of makeup causing
patinas, but who knows what they put in that stuff…
Hi Elizabeth, I've always heard that when precious metals darken with skin contact, it is the result of the body oils with the *alloys* of the metal.
Actual oils, or waxes, don’t react, but perspiration is a salt
water solution, and it does sometimes. Other body chemistry can
also affect this.
I do know that by rhodium plating the inside of rings worn by people with this problem, it can be alleviated.
rhodium is not only inert, but is very hard and resistant to
abrasion.
Obviously higher karat golds would have less problems, right?
They will have less problems with perspiration or body chemistry
caused darkening, as well as problems with rashes caused by
copper or other alloy components in the gold.
I certainly haven't heard of makeup causing patinas, but who knows what they put in that stuff....
Makeup is one of the biggest causes of staining, both on
clothing and on skin. Many makups contain pigments such as tin or
cerium oxide. These are similar to polishing compounds and if
rubbed on the gold, will do the same as polishing compounds on a
buff will do. Brighten the gold/silver, while turning the buff
black. A little of your makeup on a white scrap of cloth will
tell you easily enough, when rubbed on your jewelry, if it’s a
possible cause of problems, but you can also tell by what’s
happening. If the jewelry itself is discoloring, or if stains on
the finger are accompanied by rash or irritation, then it’s not
so likely the makeup, but a chemical interaction with the skin.
If the metal seems clean enough, but the skin or clothing is
turning dark, then it’s likely either makup, or with new
jewelry, residual polishing compound left on the jewelry and not
completely cleaned off before delivery to the customer. And of
course, you can have combinations of the above…
Peter Rowe
Hi Peter That is very helpful. After reading the comments and
discusssing the we started realizing that there was
some abrasive acting on the metal. I like to understand not only
for my customers but for myself. Thanks again Elizabeth
I don’t know about Stuller’s products but we do find that
sometimes we have customers who come in with darkening on their
14k and 18k jewels that we make for them. I know it isn’t the
alloys we use because if it was everyone would have this reaction
and all of my customers would come back with their pieces. I
believe it is that certain people exude different chemicals and
toxins from their pores and that some of them react with the
jewels. We have seen this problem on and off over the years and
I have never been able to track any patterns in the people it
happens with. Some people also work with chemicals that will
sometimes react with the metal ( we work with a lot of bio tech
and chemists in our area). Stuller’s disclaimer may be because
they have had some complaints over the years but I can’t believe
that their formulas are that much different from other suppliers
that they would have this problem more than other people.