rolling caps

From:  Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent:  Tuesday, June 23, 1998 12:34 AM
To:  Tesla List
Subject:  Re: rolling caps

Hi Kevin,

> From:  Kevin Wahila [SMTP:kevinw-at-stny.lrun-dot-com]
> Sent:  Monday, June 22, 1998 7:22 AM
> To:  tesla-at-pupman-dot-com
> Subject:  rolling caps
> from an old message.....
> "The second problem, rolling the capacitor consistently is necessary 
> because you have to roll it up first, mark where the connections go, 
> unroll it, put the connections on it, and roll it back up.  I use a piece 
> of PVC pipe with a slot cut in it.  I put the end of the aluminum plate 
> and plastic sandwich in the slot before rolling it up.  I use hose clamps 
> to squeeze the pipe down so that it grips sandwich better.  Once I have 
> the pipe on the end, I roll the thing up with the pipe in the middle.  
> If you hold the pipe in something such as a vice or lathe chuck, you can 
> roll up the capacitor, mark it, unroll it, and re-roll it so that the 
> marks line up properly."
> is it bad to just make the connections, one on the end of one plate and one
> the oppostie end of the other plate and roll it once?

The best caps have foils extending out each side and simultaneously 
connected. Otherwise you have a rather large distributed series 
inductance and resistance path the current has to traverse.