Re: homemade rolled cap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Karl Lindheimer <karl@xxxxxxxxxxxxxxx>

Hi Bobby,

When I first got started in this fascinating hobby, I was on a low budget 
also.  I guess I worked my way up through the ranks by first:
Building a "Party Cup Capacitor"  This was a simple, no-cost first 
attempt.  After a few minutes of "first light" the cap would vibrate like a 
speaker and not work too well.

Next, I built a flat "plate" capacitor using thin picture frame glass and 
aluminum sheets.  This worked somewhat, but not too well.

I then built a rolled cap using overhead transparency sheets sandwiched 
between aluminum foil sheets.  I needed two in series for the voltage I was 
pushing.  The result:  about 10 minutes of great sparks, then shorting.  By 
this time, I was hooked, and I then proceeded with another cap design.

I used plastic 2 liter soda bottles in a salt water bath, 1 liter seltzer 
bottles, Corona Beer bottles, and even battery jars in salt water to 
attempt to make a low cost, decent performance cap.
Eventually, I discovered that the Corona beer bottles made a decent cap, 
and led to the best streamers I had to date.  Moving copper jumpers, and 
adding or subtracting bottles allowed for fine tuning.

However, I eventually built an MMC array.  I spent about $11.00 on digikey 
poly HV caps, and in under an hour I built a cap that gave the best 
perfomance to date, in a tiny package.  It is still performing like a 
champ, 2 years later.  However, I gained precious first-hand knowledge 
about capacitor theory and design with all of my previous attempts.

I hope this posting offers you a little insight into the various capacitor 
methods.

Best Regards,

Karl
On Feb 24, 2005, at 9:40 AM, Tesla list wrote:

> Original poster: Bobby Amaya <dimon20042004@xxxxxxxxx>
>
> Hi everyone,
>
> Can anyone tell me how to build a good high
> voltage(40+kv) rolled cap that is not extreemely
> expensive?uilt a
>
> =====