Re: circuit board caps

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

Original poster: "Matthew Smith by way of Terry Fritz <twftesla-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>

Hi JJ

I remember from a book that I once had [but left behind in a move - sob
:-( ] of 1930's vintage - "High Voltage Physics" - that stated that the
authors found "plasticine covered with a smear of high temperature
grease" to be a good vacuum seal.  

>From my own experience, I have found that the likes of epoxy - applied
externally to the vacuum vessel *whilst it is under vacuum* performs
well.  (It gets sucked into any gaps and crannies, blocking them.)  I
think that silicone sealant would probably work well if applied in a
similar manner.  The advantage of silicone would be that it can be cut
easily, should you need to get back in there...

Using the string (exactly as below) on Google, I found some likely
material for dielectric breakdown voltages:
"dielectric breakdown voltage" "circuit board"

http://www.ipc-dot-org/html/tm2.5.htm looks likely for you.

Hope this helps.

Cheers

Matthew Smith

Tesla list wrote:
> 
> Original poster: "Janet Johnson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jpjmassage-at-earthlink-dot-net>
> 
> Hi,
> Does anyone have an idea of what the dielectric breakdown voltage of PTFE or
> other circuit board materials might be?  I asked a question about this a
while
> ago and then didn't consider it much further but we have a bunch of 10 to 30
> mil thick, 2x3 foot sheets of sample material at work that we haven't
used for
> years.  If the dielectric could handle the voltage I think it would make a
> viable tank cap.  You'd probably still want to encase it in oil and
remove the
> air though.  BTW how could you make a good vacuum seal?  Thanks for any
> ideas...
> 
> JJ - SLC