Re: cap specs or non-specs

Tesla List wrote:
> >From bigr-at-teleport-dot-comFri Jun 21 12:19:30 1996
> Date: Thu, 20 Jun 1996 23:22:47 -0700
> From: bigr-at-teleport-dot-com
> To: tesla list <tesla-at-pupman-dot-com>
> Subject: cap specs or non-specs
> Big snip here...

Rob wrote:
> Finally, I am wondering about home built caps.  Tesla used bottles
> filled with salt water (no- not the cheapo seamed bottles of today,
> but real blown ones made out of decent quality glass- would probably
> be impossible to obtain except by custom manuf. by some glass blower)
> Using modern materials, maybe I am reinventing the wheel again, but
> what about polypropylene film caps using dieletric sandwitched between
> some thin brass or other metal and compression adjusted like in the
> small trimmer caps. It seems like an oil impregnated version of this
> would be ideal and cheap for amateur to build.  Poly sheeting is avail
> in many thicknesses from hardware stores.
> Best Regards. Rob.


You may be new to the list, but most of the Tesla coil folks who now 
build their own caps (hombrew) use either polyethylene or polypropylene 
sheet with foil or flashing plates in either flat plate or rolled units 
under oil.  The old days of the glass plate or salt water caps are pretty 
much gone, unless a new guy latches on to some old outdated text.

The list is filled with cap chatter because this is the biggest bugaboo 
pestering good coiling.  We could almost go in business providing stress 
tests to caps beyond even mil spec tolerances!

Your other points about specs for caps are well taken.  Being an engineer 
myself, I always spell out every spec to my cap maker and demand impulse 
tests prior to shipment.

Richard Hull, TCBOR