Re: Cap materials
Subject: Re: Cap materials
Date: Thu, 17 Apr 1997 22:06:51 -0700
From: Bert Hickman <bert.hickman-at-aquila-dot-com>
Organization: Stoneridge Engineering
To: Tesla List <tesla-at-pupman-dot-com>
> From: Lord Talimar" <lordtali-at-mill.tds-dot-net>
> To: "Tesla List" <tesla-at-pupman-dot-com>
> instead of mineral oil, try vegetable oil. fairly close in dielectric
> value, and cheaper and easier to get a hold of.
> Hope this helps.
> > I'm about to start building some rolled poly caps, and have a question
> > about sourcing materials. .09" thick polyethelene is not commonly
> > available, but .006" thick is. Is it reasonable to use 16 layers of
> > this
> > thin stuff, or would this many layers be totally unwieldy?
> > I don't have access to a vacuum pump to pump the cap down to remove air
> > bubbles. Would the multi thin layers pose a greater problem in
> > harboring
> > air bubbles?
> > Also, for the mineral oil, what kind of place does one go to for this?
> > Auto supply store?
> > Gary Lau
> > Waltham, MA
Gary and Lord,
Well... not quite. Mineral oil doesn't go rancid with time - while some
vegetable oils may unless they contain anti-oxidants. Also, all
vegetable oils tend to have higher dielectric constants than mineral oil
(2 - 2.2). For example, cottonseed oil is about 2.7, olive oil comes in
at about 3, and castor oil ranges from 4 to 5. Unless you buy pre-dried
oil prepared for electrical use, you may also have an undesirable amount
of water in the vegetable oil you use.
Safe cappin' to you!
-- Bert --