Re: Homemade caps vs. MMC's

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

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