Re: Salt Water Resistance

To: tesla-at-pupman-dot-com
Subject: Re: Salt Water Resistance
From: Jim Lux <James.P.Lux-at-jpl.nasa.gov> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Mon, 14 Sep 1998 17:17:24 -0600
Approved: terryf-at-verinet-dot-com

Tesla List wrote:
> 
> Original Poster: "Gregory R. Hunter" <ghunter-at-enterprise-dot-net>
> 
>
> 
> Conclusions?  (1) Salt water is a pretty lousy conductor.  (2) At least at
> 1.5vdc, salt water resistance seems largely to be a function of contact
> area. 

You got it there... The contact area is probably the most important
thing. Try a couple pieces of copper pipe (or one of those copper/bronze
or stainless steel pot scrubbing pads.

 (3) I've got to find something better than plain salt water--NaCl
> plus epsom salts perhaps?  Copper Sulphate?

They all work about the same, within an order of magnitude. Choose your
salt for other desired properties (i.e. lack of corrosion of copper,
cheapness, etc.)

> 
> I don't know how relevant my experiment is at 15kvac.

Very relevant... The resistance will be the same at HV as at LV, except
for things like corona losses.
Salt water resistors are really useful, unless you need very low
resistance and high voltage (in which case, things like nichrome wire
are useful) or good temperature stability (which a salt water resistor
is never going to give you).