Re: Rubber toroids

To: tesla-at-pupman-dot-com
Subject: Re: Rubber toroids
From: Tesla List <mod1-at-pupman-dot-com>
Date: Thu, 16 Oct 1997 15:17:42 -0600 (MDT)
Approved: mod1-at-poodle.pupman-dot-com

---------- Forwarded message ----------
Date: Thu, 16 Oct 1997 11:20:58 -0700
From: Jim Lux <jimlux-at-earthlink-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Rubber toroids 

> Hi All,
> I was just wondering if anyone had tried the chrome spray that is
> usually sold in automotive stores.  I was planning to try it when I got
> to that point.  Is it conductive?  It sure would look cool.
> Just another empty thought!

I've experimented with some varieties of spray paint vis a vis
conductivity.  We used to have a bunch of Krylon Ultra Flat Black which was
somewhat conductive, since it used carbon black as the pigment.  However,
when I was trying to make a large high value resistor by using it on a
piece of plastic pipe recently, it is now an insulator.  Perhaps it has
been reformulated.

The "aluminum" paint uses aluminum powder as a pigment and is sometimes
conductive, depending on how much binder (i.e. plastic) is mixed with it to
hold it on the surface.  The easiest way to test it is to spray it on
something, let it dry, and use an ohmmeter.

I might point out that films like this have a problem with high current
densities, i.e. where a spark or arc contacts the surface.  I've used
aluminum and black paint to make conductive objects to hold a static charge
or for shielding, but if you arc (or spark) to it, it burns the paint off
at the spot the spark hits. After a while, you don't have a uniform layer
anymore.  Some sort of plating process is probably a better bet