Re: coil discharge color

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

We're getting a tad off topic here... but.. potassium does make a purple
flame, but it's very faint, and is usually masked by other colors. Sodium
makes a strong yellow flame, and a small sodium contamination, as from
sweat, will totally mask the potassium purple.
For what it's worth, potassium chloride is quite innocuous to eat == low
sodium salt substitute is a mixture of KCl and NaCal. It has a slightly
more bitter taste than ordinary table salt.. I don't know for sure, but
I'll bet it is on the GRAS (Generally Recognized As Safe) food additive list. 

It's only if it is injected into your blood that it's a problem (where it
interferes with the functioning of your nerves, in particular, the ones
running your heart).  If you were to consume a LARGE amount of potassium
chloride you'd probably die, but the same is true of sodium chloride.

On the subject of blue/purple sparks:

As Conkling (Chemistry of Pyrotechnics, 1985) mentions: "The generation of
an intense, deep-blue flame represents the ultimate challenge to the
pyrotechnic chemist".  Copper monochloride seems to be your best bet, but
it's easy for the chemistry to go off (say due to oxygen excess) and form
copper oxide or hydroxide, which both emit in the green. Copper/Arsenic
compounds were popular in the past, but have obvious disadvantages.

However, for blue... isn't the spark itself nice and blue...

Your real problem on making colored sparks using pyrotechnics schemes is
that the optimum temperature for exciting the ions is substantially lower
than the temperature of the plasma in the spark (i.e. a 1000-2000C as
opposed to 7000-10000 C).  Get that stuff too hot and it either
dissociates, or ionizes to a unproductive (color wise) state.


Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<RQBauzon-at-aol-dot-com>
> 
> lead and potassium chloride yield purple flame.  if using potassium chloride,
> don't get it into your blood.  thats one of the chemicals used in lethal
> injection.  good luck. i'm pretty interested in arc color alteration too.