Re: colored sparks

["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>

I have some empirical experience with making colored sparks in a Jacob's
ladder or regular old "drawn spark" type gap.  Covering the electrodes with
an appropriate salt (i.e. SrCl2 (red), NaCl(yellow), BaCl2 (green)) will
make for brightly colored sparks. In fact, painting bands of the different
chemicals on the Jacbos ladder electrodes will give you sparks that change
color as they rise, a very nifty and novel display. A fine mist of a water
solution sprayed into the arc will also color it.  I suspect that a fine
dust blown into it by a "Penberthy" rig (essentially a dust aspirator) would
also work.  We did do some fooling around with a chlorine rich mixture by
adding HCl to the spray mixture, which (aside from producing more vaporized
HCl.. don't breath any of these things), seemed to make the color more
consistent (probably because the HCl provides a nice Chlorine donor)

I haven't tried it on a TC.  The arc energy on a small coil is substantially
different in form/magnitude than a Jacob's ladder.

The design requirements for pyrotechnics are somewhat different than for
lighting up a spark.. In a firework, one needs stability, solid, self
contained energy source.. The chlorates and perchlorates solve a lot of
problems all at once (oxidizer, chlorine donor, etc.), and do it in time
tested mixtures (fuel, oxidizer, colorant) which have centuries of
development behind them.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, November 24, 2002 9:59 AM
Subject: Re: colored sparks


 > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dgoodfellow-at-highstream-dot-net>
 >
 > There are two factors to consider in the production of colored flame.
First
 > is the temperature that the flame is burning at, the second is the
presence
 > of a chlorine donor. Introducing the spectra imparters into the arc
remains
 > another challenge. How do you intend to introduce the components into the
 > coil's streamers?
 > Some of the components used in producing various colors are:
 >
 > Red- strontium, usually purchased as strontium nitrate or strontium
 > carbonate
 >
 > Green- barium, in the form of barium nitrate, barium carbonate, or barium
 > chlorate
 >
 > Orange- calcium, as calcium carbonate
 >
 > Blue- copper, such as copper oxychloride, copper acetoarsenate, copper
 > oxide, copper carbonate
 >
 >
 > Chlorine donors come in the form of powdered pvc, hexachlorobenzine,
parlon
 > (a chlorinated rubber) and mercurous chloride (long gone)  The chlorine
 > donor has to burn at a temperature that is compatible with the color
 > desired. If the chlorine donor does not give off it's chlorine atoms in
the
 > temperature range for the color desired, you will either have the  flame
 > color getting washed out, or driven into a higher temperature color.
Another
 > factor to consider is this- what would the temperature of the arc itself
 > coming from the top of the Tesla coil have on the chemicals that we have
 > somehow managed to introduce into the arc?
 >
 > Now, if we could mix a slurry  of say, strontium carbonate and water,
spray
 > it all over our toroid until it has an even coating, then allow it to
 > completely dry, would that give us red sparks? I tend to think it would
 > probably not.  We would want to exclude any sort of oxidizer, because
 > naturally, we would not want the toroid to immediately go up in flames.
 > Therefor, it would stand to reason that the only way to have colored
sparks
 > would be to have the spectra imparter combined with about 10% chlorine
 > donor, and no fuel or oxidizer as would be found in  pyrotechnic devices.
 >
 > The problem is this- much of the color production in colored flames
depends
 > on the oxidizer as a primary or secondary chlorine donor. Look at the
 > typical oxidizers used in color pyrotechnics:
 >
 > Potassium perchlorate
 > Potassium chlorate
 >   Ammonium perchlorate
 >
 > Again, we don't want the toroid to become a fireball, so oxidizers are not
 > an option, though essential for colored flames.
 >   This might be a good place to start: Grind up some Tums antacid in a
coffee
 > grinder (calcium carbonate) then take a piece of pvc pipe to a belt sander
 > and turn a portion of the pipe into powder. Mix the two: 90% tums and 10%
 > pvc powder (by weight). Introduce this to the coil's arcs however you see
 > fit, and if successful, you may notice an orange color. You will not be
 > breaking any laws by combining these components. You can do this without
 > having to order from pyrotechnic suppliers, but if you do see a colored
arc,
 > then you may want to venture into a strontium compound.
 > An excellent source for supplies can be found at www.skylighter-dot-com  . The
 > Tesla coil hobbits should read some of the "articles from our email
 > bulletins"  where you can learn how to make Tikki torches that have green
 > fire. Surround your Tesla coil with them for next year's Halloween!
 > I would like to hear the results from anyone that attempts to produce
 > colored arcs.
 >
 > Dave
 >
 >
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Saturday, November 23, 2002 11:05 PM
 > Subject: colored sparks
 >
 >
 >  > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
 > <BA1ELECTRONICS-at-aol-dot-com>
 >  >
 >  > I would like to know the chemicals i need to get at a fireworks supply
 >  >
 >  > place to make colored sparks.
 >  >
 >  > thanks
 >  >
 >  > bart.
 >  >
 >  >
 >  >
 >
 >