Re: colored sparks

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

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.
 >
 >
 >