Re: vacuum and poly capacitor (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 13 Sep 2007 21:06:44 -0700
From: huil888 <huil888@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: vacuum and poly capacitor (fwd)

Scott -

I think the more conventional approach is to first fill the cap with oil, 
and then gradually apply vacuum. At the beginning of my Tesla coil 
experimentation I built three rolled capacitors in 6" PVC tubing with .060" 
polyethylene and super-thick aluminum foil, filled with Shell Diala-X HV 
insulating oil. I also used a "tee" fitting at the top of the cap, but had 
one leg of clear polyethylene tubing going straight up for about 20", then 
coming back down to the vacuum pump inlet. The other leg of the "tee" went 
to a small bleed valve. After filling the cap with oil, I connected up the 
vacuum pump & bleed valve. Fir degassing, first open the bleed valve and 
turn on the vacuum pump. Then, slowly close the bleed valve. At first, the 
air between the layers of the cap (and the air dissolved in the oil itself) 
will very vigorously boil and froth. The vertical leg of clear tubing allows 
you to control the bleed valve & the vacuum level to avoid having oil froth 
being sucked out of the cap and into the pump. The amount of boiling and 
frothing will gradually diminish, and eventually you will be able to close 
the bleed valve completely and apply full vacuum. The slightest defect in 
the gluing of your endcaps will result in a huge vacuum leak, even if it is 
small enough not to leak any oil.

Regards,
Scott Hanson


----- Original Message ----- 
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Thursday, September 13, 2007 6:47 PM
Subject: vacuum and poly capacitor (fwd)


> Scott,
>
> Dave Baehr and I have both used vacuum to outgas a rolled cap.  I used a
> vacuum pump and made sure that the enclosure was very air tight.  I used a
> 6" PVC pipe with cap and then filled the bottom with epoxy up and over the
> bottom of the pipe.  I used a T fitting and a threaded hole in the top of
> the cap.  On one leg of the T the vacuum pump pumped and the other end I
> clamped off the tube into the oil.  I then pulled a vacuum and once that
> was done opened the oil line.  Make sure you close off the vacuum pump to
> avoid putting oil into it.
>
> Chip
>
> ---------- Forwarded message ----------
> Date: Thu, 13 Sep 2007 20:52:48 -0400
> From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: vacuum and poly capacitor
>
>
> Hey guys,
>     Would it be worth my time to build a poly-plate cap, out of PE
> plastic and aluminum foil, and suck the air out of it with a vacuum pump,
> before backfilling with oil (I know this is the era of the MMC, and I
> actually don't even need a capacitor right now, but I have hundreds of
> feet of 6 mil PE greenhouse plastic, which should make a decent cap if I
> use about 10 layers).  My question is, If I use my air-conditioning
> compressor (which I have used successfully for plasma globe work), what
> kind of enclosure for the cap do I have to build, air tight, or just oil
> tight, also when and how do I apply the vacuum.  Or, since I have so much
> plastic, should I just not worry about the vacuum.  Like I said, I am
> mostly toying with the idea, I am not in any immediate need of a cap right
> now.  Thanks. Scott Bogard.
>
> _________________________________________________________________
> Capture your memories in an online journal!
> http://www.reallivemoms.com?ocid=TXT_TAGHM&loc=us
>
>
>