Re: Dielectric constant table

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

Original poster: The MCP <ejkeever-at-comcast-dot-net> 

I originally went with trying to make a homemade cap because I could get the
materials I need for $13 (10 for mylar, 3 for mineral oil). When that totally
did NOT work out, I dropped it and picked up the professional quality caps
from E-Bay, ultimately totaling $85 for 3. Ok, now that that's cleared up...

On Thursday 18 September 2003 04:33 pm, Tesla list wrote:
 > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
 >
 > Hi,
 >
 > I just wanted to be sure you were aware that nobody makes homemade oil caps
 > anymore.  A new cap called the "MMC" has totally replaced them now
 > days.  When MMC came on to scene, many people just stopped there oil filled
 > cap projects right in the middle and never went back...  See:
 >
 > http://hot-streamer-dot-com/TeslaCoils/MMCInfo/mmcinfo.htm
 >
 > http://hot-streamer-dot-com/temp/MMCcapSales.gif
 >
 > http://www.thegeekgroup-dot-org/mmc/
 >
 > Or, just search on Google for "mmc capacitor"...
 >
 > Perhaps you really do want to make one of the obsolete types still, but
 > just want to be sure you don't go to all that work for no reason.  Since
 > the MMC, I think most of the rolled poly cap technology sort of stopped
 > dead.
 >
 > Polypropylene is the "best" material by far.  Caster oil gives good high
 > values and is used in some commercial caps.  The only drawback is the high
 > cost.
 >
 > As for "novel materials", to my memory, there have been zero sucesses...
 >
 > Cheers,
 >
 >          Terry
 >
 > At 04:13 PM 9/18/2003 -0700, you wrote:
 > >I'm wondering how long it's been since the dielectric tables present on
 > > many tesla coil sites have been updated.
 > >
 > >I'm also wondering about some of the values on them. For example, the
 > > table says that Mylar is good for 7.5Kv *per mil*. However, one of my
 > > early attempts at a cap using 10 mils of mylar failed at 5000V rms.
 > > Something is wrong.
 > >
 > >Also, a suggested addition... the giant table at
 > >http://www.asiinstr-dot-com/dc1.html says that hydrogenated castor oil has a K
 > > of about 10 at 80* F.
 > >
 > >Speaking of which - Anyone ever considered novel materials to build a
 > >capacitor? For example, Iodine? Iron oxide? Copper oxide?