Re: Homemade caps vs. MMC's

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

Original poster: "Crow Leader by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla-at-lists.symmetric-dot-net>

Teflon capacitors exist. they are very expensive and tend to be larger than
caps of other dielectrics. They are used for high temperature caps.

KEN

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, August 18, 2002 8:54 PM
Subject: Re: Homemade caps vs. MMC's


> Original poster: "Craig Fuller by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<cbfull-at-hotmail-dot-com>
>
> Thanks for the comments Terry!  I will try to get a photo of one.  After
> checking your links, I realize that the caps I have do not state whether
it
> is an AC or DC rating.  I can only guess that it is an AC rating because
> they have handled so well.  I did take a look at the links someone posted
> about the "uno" MMC needing a home, and my caps look identical to those on
> the outside.  I can't see the markings on theirs though.
>
> Maybe one day some engineer will figure out how to make very powerful and
> compact capacitors using PTFE or some other fluorinated polymer instead of
> polypropylene.  These polymers are well known for having considerably
higher
> dielectric strength.  McMaster Carr sells fluorinated ethylene-propylene
> film by the foot, but it's kind of expensive for the typical basement
> tinkerer.
>
> Craig
>
> >From: "Tesla list" <tesla-at-pupman-dot-com>
> >To: tesla-at-pupman-dot-com
> >Subject: Re: Homemade caps vs. MMC's
> >Date: Sat, 17 Aug 2002 16:52:31 -0600
> >
> >Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> >
> >Hi Craig,
> >
> >At 05:34 PM 8/17/2002 -0400, you wrote:
> > >Hi all,
> > >
> > >I have been using MMC's since my very first coil back in 1988.  Some
guy
> >who
> > >had his own electronics shop here in Ohio sold me two bags of 100 caps
> >for
> > >10 bucks.
> >
> >One of the best deals I have heard of :-))
> >
> > >I had no idea at the time that they would be so useful.  They are
> > >rated at .224uF and 1000V each, which is just perfect.  I can make a
> >string
> > >rated at 45,000V and 0.050uF, and as I increase power, I just parallel
> > >another string.  The best part is, after 20 minutes of operation, they
> >don't
> > >even get warm!  I have looked for more on the net just to see how much
> >they
> > >cost but I can find nothing to match.  What a lucky find.  Maybe I can
> >take
> > >a picture of their markings in case someone would recognize the
> > >manufacturer.  Anyone interested?  I don't have a website so you would
> >have
> > >to put them up on your own.
> >
> >If you send me a picture I can probably figure it out or post it.
> >
> >terry-at-hot-streamer-dot-com
> >
> >You can also just get Cornell Dubilier type 942C.
> >
> >http://www.cornell-dubilier-dot-com/misc/h942.htm
> >
> >http://www.cornell-dubilier-dot-com/film/9421000.htm
> >
> >942C10P22K
> >
> >Richardson can get them eventually:
> >
> >http://www.rell-dot-com/
> >
> >http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=84181&PNO=&PNM=
> >
> >They are $1.54 with a minimum quantity of 45.
> >
> >Geek group style 0.150uF 2000VDC may give a little more bang for the
buck.
> >
> > >
> > >Also, I never considered building my own from polyethylene and mineral
> >oil
> > >because as a chemical engineer, I was pretty sure that the mineral oil
> >would
> > >slowly permeate the polyethylene because of their chemical similarities
> > >(like dissolves like, for those of you who have not taken general
> > >chemistry), and eventually, almost certainly, cause the PE dielectric
to
> > >fail.  So I recommend that anyone looking for a cap to use on their
coil,
> > >save yourself the frustration and don't risk using the classic homemade
> >cap
> > >recipe.  Just  look for suitable caps to make a MMC.  You won't regret
> >it!
> > >
> > >Craig
> > >
> >
> >I have not heard of anyone making poly caps in a long long time now :-))
> >
> >Cheers,
> >
> > Terry
>
>