Re: Saran Wrap as a Dielectric

["David Huffman" <huffman-at-fnal.gov> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

What ever happened to truth in labeling? I thought I remembered seeing
polyethylene on the label. Bert, where did you find out different? Just
curious.
Dave
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, August 30, 2000 9:37 PM
Subject: Re: Saran Wrap as a Dielectric


> Original poster: "Bert Hickman" <bert.hickman-at-aquila-dot-com>
>
> Tesla list wrote:
> >
> > Original poster: MaverickIce00-at-aol-dot-com
> >
> > List,
> >
> >     I recently noticed that a roll of Saran Wrap I have is Polyethylene.
It's
> > probably only a few microns thick (can't find the caliper) but if I used
> > enough layers, would it make a suitable dielectric for a capacitor?
Would it
> > be as good a dielectric as factory-manufactured LDPE? I checked it out,
and
> > it seems to be pretty clean, no chemicals or anything, but since this is
not
> > made for such a duty, would it be a bad idea to go ahead and make a cap
with
> > it? Thanks for your help.
> >
> > - Joshua
>
> Joshua and all,
>
> Common Dow Saran Wrap is not polyethylene, nor is it polyester. It's
> actually polyvinylidene chloride (PVDC), or an alloy of PVDC and
> Polyvinyl Chloride (PVC), and is a member of the PVC family of polymers.
>
> Unfortunately, if you thought PVC was lossy, PVDC is even 5-10X lossier!
> Don't bother using this stuff as a capacitor dielectric for RF use -
> it'll act more like a resistor! Use plain old Low Density Polyethylene
> dropcloth or polypropylene sheet protects instead... or make an MMC from
> PP caps.
>
> PVDC's electrical characteristics (along with many other useful
> polymers) can be found at:
> http://members.tm-dot-net/lapointe/Plastics.htm
>
>                                LDPE    PP      PVC   PVDC
>                                ====    ==      ===   ====
> Dielectric Strength (V/mil):
>    0.001" Material             5000   8000      -      -
>    0.005" Material             3000   2700      -      -
> Dielectric Constant:
>    1 kHz                        2.2    2.2     3.0    3.9
>    1 MHz                        2.2    2.2     2.7    3.0
> Dissipation Factor:
>    1 kHz                      0.0003  0.0003  0.009  0.052
>    1 MHz                      0.0003  0.0003  0.006  0.050
>
> Safe cappin' to you!
>
> -- Bert --
> --
> Bert Hickman
> Stoneridge Engineering
> Email:    bert.hickman-at-aquila-dot-com
> Web Site: http://www.teslamania-dot-com
>
>
>
>
>