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Re: Rubber toroids [ graphite ]
From: Wes A Brzozowski[SMTP:wesb-at-blue.spectra-dot-net]
Sent: Tuesday, October 28, 1997 7:13 AM
To: Tesla List
Subject: Re: Rubber toroids [ graphite ]
On Sun, 26 Oct 1997, Tesla List wrote:
>
> From: Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
> Sent: Saturday, October 25, 1997 3:19 PM
> To: Tesla List
> Subject: Re: Rubber toroids [ graphite ]
>
> Again remember the one downfall of using copper chloride is it plates fast
> and this results in courser deposits of copper which increases the tendancy
> to flake. It's a good idea to burnish down the copper after your done
This is not so much a "downfall" of copper chloride as it is a downfall of
a non-acid solution. You'll get the same results with plain copper sulfate
solution. The speed of the plating is really due to the current; not the
fact that you're using copper chloride. It's the copper(II) ions that are
acting in the plating, and wether there are also sulfate radicals or
chloride ions in the mix matters not (at least where the plating is
concerned; as in other messages here, there are other products that may
also form due to the presence of chlorides). In order to make it possible
to speed up the plating and do it smoothly, sulfuric acid is added to the
bath. This also improves adhesion of the copper, which is probably related
to the smoothness of the plate. Of course, if you add sulfuric acid to
a fairly concentrated chloride solution, you could be overcome by HCl
fumes; at the very least it should be an irritating experience. But with
that acid you can plate furiously fast. So fast in fact, that some parts
are electroformed; solid copper parts (not foil; inches thick!) are built
up by additive plating and the parts are solid. Do that with a non-acid
solution and you'll get something you can crumble between your fingers.
Non acid plating will give the spongy surface you described.
Burnishing will hide some of the problem by making the surface look
smooth, but in fact you'll have a porous layer of copper that may or may
not adhere well and may or may not hold up, depending on what type of
handling the work peice will eventually see.
> plating and a second plating of either nickel or chromium will make not
> only a more durable finish but a better looking one at that! BTW if you use
Well now, as if the possible problems of nickel plating weren't bad
enough, now we're talking about chrome plating! You can try whatever you'd
like, but here are the types of problems to expect:
1) You must control both the temperature of the bath and the current
density over the entire surface of the work peice. If you're out
of the "sweet range" for this temperature/current density graph,
you get a plate that's milky or grey, and which can't be corrected
after the fact.
2) The chromic acid electrolyte (or any chromate, for that matter)
will attack your skin and mucous membranes, and will cause lung
cancer over time. The current density requirements for a shiny plate
will have the bath effervescing furiously, spraying a mist of the
stuff into the air. Covering the bath will help, but not eliminate
the problem unless the vat is very carefully designed. This will
cost $$$$, and you can't afford for it not to work exactly as
designed. That is, you can't tweak it like a coil; either it
worked properly the first time or you have a toxic discharge.
3) You are working with hexavalent chromium; the very worst kind. At
least in the USA, the ammount of hexavalent chrome you're allowed
to discharge in the waste water is down in the parts per million
range. (It kills fish quite readily, otherwise). If you don't mind
breaking the law and risking significant fines, you might consider
rinsing various utensils you use in the sink, but if you're gonna
play it right, even the rinse water from the work peice is hazardous
waste and must be disposed of properly, or laboriously evaporated
down and added back to the bath.
4) Something will eventually have to be done with the plating solution.
You're creating a very costly toxic waste disposal problem for you or
your heirs.
5) A spill in your house/workshop or a coating of the stuff settled out
due to uncontained effervescence will make you the owner of a
genuine hazardous waste site, in the eyes of our all-knowing,
all-caring federal government (in the USA). How you want to treat
this is your business, but at least be aware of the liabilities
before proceeding.
That said, the original suggestion of chrome plating is in my opinion,
much preferable to nickel; both due to the quality of the plate and the
possible safety issues. But I'd take my work peice to a commercial plater
for this one.
> copper sulphate and you want an even finner finish of copper deposite add a
> little sugar to the plating soloutine, it acts as an inhibitor and slows
> down the plating process, in theory it should work with the copper chloride
> too but I've ever tried it.
Old time platers had all sorts of secret additives they'd add to the bath
for one reason or another. Some of them actually worked and the reason
that they work isn't always understood, even today. But the range of
additive that works may not be too far from the range of additive that
contaminates your bath, so the suggestion to "add some" might be taken
with a bit of caution. Try some small test peices in small vats, and take
lots of data.
Wes B.
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