Re: L/ D & H/D poly

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: L/ D & H/D poly
From: Tesla List <tesla-at-stic-dot-net>
Date: Sun, 23 Nov 1997 23:31:07 -0600
Approved: tesla-at-stic-dot-net

From: 	Thomas McGahee[SMTP:tom_mcgahee-at-sigmais-dot-com]
Sent: 	Sunday, November 23, 1997 1:47 PM
To: 	Tesla List
Cc: 	rchowes-at-email.msn-dot-com
Subject: 	Re: L/ D & H/D  poly


> 
> From: 	Raymond C. Howes[SMTP:rchowes-at-email.msn-dot-com]
> Sent: 	Saturday, November 22, 1997 11:49 PM
> To: 	Tesla List
> Subject: 	L/ D & H/D  poly
> 
> Hi all,
> I work in a window business and monday of this week a plastics sales rep
> came in.
> What luck!      I asked if they carried polyethylene sheets, and yes they
> do.
> He said they had 2 types, low density  and high density, both were at 6 mil
> he thought.
> My question is which would be better for a cap?   L/D would be $30 bucks for
> a 4x8
> H/D would be $34 for a 4x8 sheet. He also said that the H/D was a little bit
> more
> rubberier than the L/D. ( His discription!)
> I kind of explained what I wanted to do with it, but he had no idea of the
> use for electrical puposes. He just sells the stuff and he can get it if I
> need it.
> Again I want to say thanks for all the help I have recievied with my first
> coil. I,m just trying to make what I have better.
>                                                             Thanks ,Ray
> 
> rchowes-at-msn-dot-com
> 
> 
Ray,
the LD is prefered for rolled caps. For flat plate caps, either is fine,
though I personally prefer the HD in flat cap designs. It is just a 
matter of *rigidity*. HD is more rigid. All other factors are about the 
same as far as coiling is concerned.

Are you sure he didn't mean 60 mils? The prices you quoted would be in
the ballpark for 60 mil, but awfully expensive for 6 mil. You can
buy 6 mil poly sheet in large rolls at any big hardware supply store
for much less than $30 for the amount quoted.

You can also use polypropylene. It is like the HD polyethelene for
all practical purposes. With either of these use 2.0 as your dielectric
constant. Yeah, I know, it is actually closer to 2.2, but that is for
pure poly... and most of this stuff is not 100% virgin poly.

Always perform a visual inspection of each sheet before using it in Tesla
service. Look for pinholes, tears, stretch marks, and imbedded material.
If a section is suspect, cut it out. You can use it for other stuff, but
NOT for your capacitors!

Hope this helps.
Fr. Tom McGahee