I have been following with interest the discussion of nickel
allergies, which I have seen and know is quite real. I still do not
seem to get the answer that i need regarding the danger (probably
through inhalation) of nickel when one anneals old silver plate
silverware. I have tried every source I know to find an answer and
most ignore the question. I can’t even find out what is the base
metal used in old silverplated silverware. When I cut the spoons or
folks the resulting slice is quite shinny. I still do not believe it
is lead because it is too shinny and too hard to bend. Does anyone
use flatware to make rings, bracelets and pendants? If so, what do
you feel about the dangers of the base metal and what do you think
/is /the base mental. I have seen some lovely patterns for
silverplate and some exquisite jewelry made as well but I am
concerned about the toxicity of nickel when heated. I am concerned
about polishing the entire piece and exposing people to possible
nickel allergies. I guess I am hoping it is made of tin but fear the
old flatware is like most kitchen and bathroom faucets which are
plated with nickel.
I am concerned about the toxicity of nickel when heated. I am
concerned about polishing the entire piece and exposing people to
possible nickel allergies.
In the first case you are unlikely to heat the nickel hot enough to
get any nickel vapor as its boiling point is 4950F. But if you are
polishing it and you do not have real good ventilation/filtering on
your polishing equipment you are breathing nickel dust. That is not
a good thing. And yes if you polish enough to remove the silver plate
you are exposing your clients to it.
Barbara P. voiced concern over hazards of nickel when heated. A
review of nickel’s physical constants and toxicity provides some
useful Nickel itself vaporizes at such a high
temperature (over 5000 deg. F.) that any chance of inhaling nickel
vapor is remote. A more toxic nickel compound that does vaporize at
low temperatures is nickel carbonyl, but even that is unlikely since
a controlled temperature much lower than your torch flame is required
to create it, and the nickel has to be in a carbon monoxide
atmosphere. So that scenario is unlikely unless your heating
processes contain a lot of carbon monoxide gas, which is itself toxic
and more likely to be of harm than any nickel present. The more
likely problem with nickel is ionic nickel created by galvanic
processes when nickel or its alloys are in contact with sweat or
acids. That is what causes an allergic reaction over time.
We can’t know for certain what is under the Silverplate without
metallurgical testing. But assuming it’s Nickel Silver with a content
of perhaps 6% Nickel, it is unlikely for you to receive actual Nickel
exposure unless you first liquify the alloy and then boil the alloy
to release the Nickel as elemental vapors. If you contact the Nickel
and develop a rash that is contact dermatitis, Nickel exposure as an
inhalant has rather low safety limits. A google search for the MSDS
of Nickel will get you those limits and more of the physical data you
want. An MSDS is usually the first place that I look, when I have any
exposure or environmental concerns. That being said, I was making
Silverplate jewelry out of flatware starting in 1972 and turned -
twisted thousands of spoons and forks over a 5 year period. Other
than sore hands from overly thick Soup Ladles, suffered no ill
effects.