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RE Arcs off the fingers and getting killed in the process...


Hi All!

I guess it is time for me to share some of my experiences and thoughts on 
having sparks jump from your fingers.  This is something that I have resisted 
doing, as Terry said "in fear of leaving something out and killing someone."  
As Terry pointed out, it is relatively easy for anyone to construct a 
potentially deadly coil and with each new coiler, there is the potential for 
someone to try and recreate this demonstration without doing the research and 
taking the proper safety precautions.  

My first introduction to Tesla coils was while working at the Memphis Museum 
in Memphis, TN.  We decided to put together a high voltage show and purchased 
two Tesla coils and tons of other equipment from Resonance Research.  From 
the first time that I saw the sparks, I was obsessed.  Originally, the show 
was presented by Roger Van Cleef (my mentor and dear friend) and Tracy Dunlap 
(the only person I have ever trusted to set up the gear for me).  Tracy was 
the first one to try the sparks from the fingers demo, after receiving 
instructions from D.C. Cox of Resonance Research.  For one second, Tracy had 
beautiful sparks leaping from his fingers.  At the same time, he learned that 
this HURTS!!!!!  In spite of the conversations that have gone on in this 
group about high frequency currents not registering on human nerve, if you do 
this demonstration, you feel it a LOT!  

That was the first and last time that Tracy ever did the demo.  While he 
continued to do the tech work on the show for the next three years, he never 
got close to the sparks again.  They were ready to forget the idea when I 
stepped in.  I had been trying to get my foot in the door for doing the show, 
and this was my chance.  We started with the variac turned way down and only 
two inches of spark from my fingers.  I was wearing thimbles with needles 
welded to them, to prevent the sparks from burning my skin.  I also had a hat 
made of copper strips, with nails welded to them, again to provide a place 
for the sparks to jump.  At first, the demo produced quite a bit of sensation 
and gave me bad headaches.  As I tell people now, after the first 500 times, 
you hardly notice it.  

At low currents, there is not much sensation, as long as the spark is just 
going into the air.  EVEN AT LOW CURRENTS, NEVER LET THE SPARK JUMP FROM YOU 
TO ANYTHING.  I can tell you from experience that this really hurts, and is 
potentially fatal.  The amount of sensation seems to be related to current 
density.  You feel it most at the point where the current moves to and from 
your body.  The larger the contact area, the less you feel it.  At low 
currents, the sensation stays at the surface, but as your sparks get brighter 
and thicker, the sensation moves inwards, contracting the muscles.  Arcing to 
a ground causes violent contraction of the muscles and I suspect that it 
could easily stop your heart with a moderately powerful coil.  

Even with sparks jumping into the air, at full power, I get enough muscle 
contraction in my feet and arms to leave me sore the following day.  I will 
add here that I have a fairly high tolerance to pain.  If you insist on 
novacaine when you get a tooth filled, you should probably steer away from 
this demo, or at least stay with very low power.  

It has taken 13 years of tinkering and experimentation to get my coil tuned 
to the point where it is small and light enough to fit into my luggage when I 
fly and still get nice sparks with the least amount of discomfort.  I am VERY 
careful about safety clearance.  I need triple the spark length betwen me and 
the nearest potential target for the sparks in order to feel comfortable and 
I prefer more than that.  

There are hundreds of other bits of information that I feel I should be 
mentioning, but to keep this from turning into a book, I will trust all of 
you to have enough sense to be safe and to do lots of research before trying 
anything that is potentially fatal.  

Robert Krampf
Science Education Company
http://www.krampf-dot-com
Get my Free Experiment of the Week by sending an e-mail to krampf-at-krampf-dot-com