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Re: Electroplating
>With the proper choice of base material, say a graphite-filled coating,
>cyanide-based plating baths offer no advantages, and their very existence
That's the main idea why I think hobbyist should avoid cyanide plating.
They are dangerous (especially without proper working conditions) and
there is not too much to gain.
>It's the nickel-carbonyl that's "so poisonous it is hard to beleive". I'd
>estimate it at perhaps 2 orders of magnitude more poisonous than
cyanides.
Well, actually I did look that one up after you'd bought the danger up
earlier.
When compared with LD50 (dose which will kill half the subjects) the are
in the same danger level.
>The hazards of handling cyanides are probably similar to the hazards of
>Tesla Coiling. In both cases, you learn the hazards, you develop safe
>procedures, and you follow them religiously, or you die. If anything, the
Well, you might get just shocked and learn from that. If you're lucky.
>problems of working with high voltage discharges are more unpredictable
>and carry more surprises, so if I were afraid of anything dangerous, and
Using good insulators and being at safe distance is easy. At least I think
it is. Grounded protective nets are easily done etc. However, toxic gases
can have effect furher away. Most people are also unaware that only about
80% of population can smell cyanides. I, for instance, know from previous
exposure that I cannot smell it at dangerous levels. Lucky to be alive and
tell you about it.
>Still, when talking about dangers in a hobby that's already dangerous, it
>seems unfair not to at least give a relative feel for the difficulty of
>managing the risk.
I think talk about safety issues is important. There may always be
some things you might not know. It is far better to hear about those
dangers you did not think of that get injured/killed/whatever.
>By the way, I was the one who originally brought up the nickel-carbonyl
>concern, and I should point out that this is only speculative at present,
>although it's worth looking at seriously. The problem is not with a
I most certainly agree. There is too little to gain. There are plenty of
other materials causing no possibility of danger. I wouln't use an
insulator if I were not absolutely sure it will not fail. I think it is
reasonable
to apply the same rule for materials and chemical dangers.
>field, concerning nickel-carbonyl. They have speculated that nickel, and
>CO2, in the presence of certain hot flames, could produce this toxin, and
As another chemist I certainly will not rule that possibility out. At
high-energy
conditions there might be a risk involved. However, while being
unqualified in
plasma or spark reactions I'm not able to comment more about that either.
The field of plasma chemistry has too much odd things for me. :)
>in an electric discharge containing atmospheric CO2. Emitting such a
>discharge from a nickel-plated surface introduces the same starting
>materials in a high-energy environment. If the toxin were produced, it
That is true. However, I'm not perfectly convinced that there are
high-energy
conditions *at* the surface. Some corona/discharge research articles
have considered the surface being covered by a ionic cloud which would
turn into a hot spark at some distance from the surface. That cloud would
also spread out the "spark" somewhat near the surface. At higher
cross-sectional area the energy density would be lower.
I will also emphasize that these articles did not have high-frequency ac.
Still, at higher frequency I'd assume ionic clouds to be much more stable
when compared with low-frequency situation. At low-frequency ac there
is much longer time for the ions to combine when there is not too much
current or voltage. At high-frequency the re-combination time is shorter
and I'd assume more stable ion clouds. Still, this is only speculation.
Even though the existance of ion cloud is well known from the fact of
rising apparent capasitance of the top load.
A good and complete explanation of high-frequency spark phenomena is
unfortunately yet to be seen. Perhaps we'll al know exactly what is
happening
at different points of spark.
--
Harri Suomalainen mailto:haba-at-cc.hut.fi
We have phone numbers, why'd we need IP-numbers? - a person in a bus