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Re: Rubber toroids
---------- Forwarded message ----------
Date: Thu, 16 Oct 1997 09:06:32 +0300 (EET DST)
From: Harri Suomalainen <haba-at-cc.hut.fi>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Rubber toroids
On Wed, 15 Oct 1997, Tesla List wrote:
> I believe that it's best to plate nickel or chrome over a copper strike, so
> you'll need to get copper plating solution, too.
Or go for electrochemical methods. I've been thinking for quite a time
of making toroids by 1st coating it with graphite and then growing some
metal (like copper) over it by electrolysis. Perhaps then another coat
like nickel by another electrolysis. I'm certain I'll try it some day.
However, getting an even coating requires a round other electrode around
the toroid or rotating the toroid in the solution. It would also require
quite a lot of solution and a fairly large tank. Everything else should
be pretty simple.
> We have some conductive nickel spray paint here at work that's used for EMI
> shielding. That might work as a base coat prior to the electroforming
> process. I'll guarantee you that any conductive paint will fry right off
> when a corona discharges from its surface.
I'd be afraid of that too. I've seen even the thin aluminum foil from the
toroid fried off. Multiple coatings seem to work.
> Home plating is kind of a nuisance (and can be dangerous if you're doing
> silver since it contains cyanide and can outgas if the pH gets too low).
Yeah, right. Almost everyone would easily think that. Even all of the
chemists around here used to think that way until proven by - ehem- an
empirical test by accident. Even in a non-oxidating solution.
Actually the silver cyanide solution will be an oxidize/reduce reaction
and it *will* outgas dicyanide (CN)2. No matter what the pH is. In acidic
solution HCN will be outgassed. Yes, you probably guessed already that
(CN)2 will react in the body and HCN or CN- iones will be formed. Then
it will start affecting dangerously.
Playing around with cyanides is not worth it. Especially not for an
hobbyist having no special equipment, knowledge and precousions.
LD50 (half of the subjects killed) for human, inhaled, for HCN is
around 1mg/kg. Make that 70mg for a 70kg man getting killed by a 50%
probability. Still you may get serious effects even from a few
milligrams. It may even be below the amount you are able to smell.
It is not fun, not even with the antidotes. Trust me, I know.
> I'd recommend that you get the process started at home by making your
> nonconductive shape conductive with a graphite base and a strike coat of
> copper; then just take it to a bumper plating shop and let them do the
> heavy buildup work. You'll need a lot of buildup since a thin plate will
> probably erode very quickly due to corona discharges.
That's vertainly a good idea. It'll keep you alive too!
--
See "Malin Tunic: Chemistry of structure - function references in cheese" for
further details!
Harri.Suomalainen-at-hut.fi - PGP key available by fingering haba-at-alpha.hut.fi