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Re: oil filled resonators



Tesla List wrote:
> 
> >From kukkonen-at-cc.hut.fiFri Oct 18 21:54:28 1996
> Date: Fri, 18 Oct 1996 12:01:10 +0300 (EET DST)
> From: Kristian Ukkonen <kukkonen-at-cc.hut.fi>
> To: tesla-at-pupman-dot-com
> Subject: Re: oil filled resonators
> 
> On Thu, 17 Oct 1996, Tesla List wrote:
> 
> >         Thanks for this valuable information. But this is rather
> > distressing. It looks as if some of the "best" plastics for our work
> > are in fact the worst when it comes to oil immersion.
> > >                 Typical      With
> > > Common          Trade           Mineral
> > > Symbol:         Name              Oil
> > > =======         =========       =======
> > > PP              -          C
> > >    C: Moderate Attack. Limited Life
> > Polypropylene scores a "C"  and Lexan!! :(
> > Polyethylene scores "B"  as does PMMA :(
> > Enjoy?  I think not but definitely worth knowing!
> > Malcolm
> 
> I would definitely not agree with PP specs above!! I have PP caps that are
> oil immersed and good after about three years..
> 
> I'd guess that it depends a LOT on the issua of what kind of a
> xformer oil one uses.. Some may be more reactive than others..
> 
> Kristian Ukkonen.
> 
> ---------------------------------------------------------------------------
> | Kristian Ukkonen       |  Do as thou wilt shall be the whole of the law |
> | kukkonen-at-alpha.hut.fi  |_____  Chance favours the prepared mind  |-------
> | http://www.hut.fi/~kukkonen |  Fear is the mind-killer  |---------
> -----------------------------------------------------------              42

Kristian,

Yeah... I had a question about that one too!. PP and PE should behave in
a fairly similar fashion. I have another source (Cadillac Plastics)
which indicates that PP is supposedly _better_ than LDPE or HDPE
regarding solvent resistance, but it doesn't get specific relative to
mineral oils. 

I suspect you're right about the type of mineral oil, since there seems
to be a fairly wide range of composition. If coilers have had good,
multi-year experience with PP using electrical grade mineral oil, then
it would seem that, at least for our use, a "B" might be warranted in
the chemical resistance chart. Thanks for the input!!

Any other anecdotal experiences? 


-- Bert --