RE: Bad Ideas

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

Original poster: "Lau, Gary by way of Terry Fritz <teslalist-at-qwest-dot-net>" <gary.lau-at-hp-dot-com>

Hi Chris, comments interspersed:

 >Original poster: "C.T. by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
<ct451-at-yahoo-dot-com>
 >
 >hi
 >
 >I've recently finished my first coil and  decided to have a look on the net
 >at what other people are creating. I came across this list and thought the
 >coil gurus might save me some time (not that it's not fun to blow things up)
 >
 >I've had my share of failures, mainly because I had no guidance and because
 >I live in the middle on nowhere and try to use what i can get my hands on.
 >I'm using a 4000v 20ma neon transformer (apparently using 4 110/220
 >transformers in series is a bad idea) and 4 3300pf/10kv soviet made
 >capacitors with unknown dielectric (home made ones didn't work - very bad
 >smell). Two pieces of pipe for the gap. My creation stands 2 feet tall with
 >guts and all. 5-6" sparks come out. Cost under $15.
 >
 >Here's what I'm trying to change on my set up and need some input:
 >
 >1) replace the two aluminum trays on top of the secondary coil with and
 >inflated inner tire tube painted with heat resistant aluminum paint. Will
 >this work?

No, aluminum paint is not nearly conductive enough.  The topic has been 
discussed at length on this List, but no conductive paint short of some 
very expensive silver compound has ever been shown to work.  And if you're 
using only a 4kV/20mA power supply, your top load should be much smaller 
than a tire.  A 3" x 12" toroid is probably as large as you want to 
go.  Just use some aluminum flex dryer duct.

 >2) I came across some capacitors that are marked 4kv 0.1uf for AC use made
 >in the USSR. I think the dielectric is paper. They are 3"x2"x6" and they
 >look that they can take some serious punishment for only $2 each. Any
 >experience with similar types?

Most caps rated for AC use are probably intended for use across the AC 
mains at 50/60 Hz, and are not intended for pulse discharge 
applications.  But yours seem to be quite large, so I can't be sure.  It's 
certainly worth a try!

 >3) is it ok to use a capacitor with much higher capacitance without
 >changing anything else on my coil? I figure the capacitor would just charge
 >up 1/3 (or some other fraction) of the charge (probably faster if the power
 >supply can keep up) before the static gap fires so there won't be a problem.

No.  Did you forget the part where the primary resonant frequency has to be 
matched to the secondary resonant frequency?  And if the caps only charges 
up to 1/3 of "full", then the spark gap won't fire.

 >4) can i use a regular 1.5" carbon-steel pipe for a ground rod instead of
 >copper? I have a bunch of those laying around.

Sure, although the connection from the wire to the pipe is likely to 
degrade over time as rust and corrosion accumulate.

 >5) how about just dropping a piece of metal tied to some wire into a 100'
 >deep well (with some water in it - probably leaking in there from the
 >sewage tanks) or even the sewage tank?

If there is 100 feet of wire between your coil and the actual ground, 
that's too far.

 >I'll save my homemade capacitor ideas for another time.

Thanks.  Not to stifle creativity, but home made caps, with the possible 
exception of salt water caps, are far more trouble than they're worth and 
will generally fail in short order.

 >thanks,
 >
 >Chris

Regards, Gary Lau
MA, USA