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Re: Polystyrene and oil?

This is interresting to me because I plan to use some polystyrene 0.023" for
a rolled cap. I guess age testing would be in order. I will place some in
transformer oil and see what happens.
Dave Huffman

-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Monday, October 19, 1998 2:10 PM
Subject: Polystyrene and oil?


>Original Poster: Marco Denicolai <marco-at-vistacom.fi>
>
>I have got 2 sheets 2 x 1 meters of Polystyrene (PS), 0.5mm (0.02") thick.
>
>Dielectric constant:                    2.5
>Dissipation factor (-at- 1MHz):            0.0003
>Dielectric strength (0.2 mm thickness): >40 kV/mm  (i.e. >1016 kV/mil)
>Water absorption:                       <0.1%
>
>So I believed that was a feasible material for my capacitors until some of
you
>mentioned that it cannot stand oil. A call to the manufacturer confirmed
it:
>they
>spoke about it standing 4 hours, maximum one week.
>
>>From the web I found a table about PS were it was possible to see that PS
>stands
>SOME oils but not ALL oils. So I tested two samples of PS:
>
>A - clear PS, 0.25 mm thick
>B - white PS, 0.5 mm thick (the one for the capacitors)
>
>I used olive (!) oil and motor oil (full synthetic). I haven't got yet
>transformer oil!
>
>Several days at 20C degrees didn't change a thing in the samples. Then I
put
>the samples
>in motor oil to bake into my furnace for 5 hours at 75C degrees. The B
>(white) sample
>didn't show any visible change. The A (clear) sample lost its transparency,
>became opaque.
>
>With the aid of a microscope I saw on the B sample a lot of microscares:
>still the sample is
>as flexible as it was before, and the scares aren't deep.
>
>I have read that silicon oil is used fro transformers and that it doesn't
>attack most of
>plactics.
>
>Do you know what is the oil you use for your capacitors ?
>
>Has anybody used PS in rolled capacitors ?
>
>
>
>
>
>________________________________________________________________________
>
> Marco Denicolai                   Vista Communication Instruments, Inc.
> Hardware Development Manager      www.vistacom.fi
>
> marco-at-vistacom.fi                 Kaisaniemenkatu 13 A
> fax:    +358-9-622-5610           SF-00100 HELSINKI
> phone:  +358-9-622-623-15         Finland
>
>   Remember, Murphy was an optimist! I am not...
>________________________________________________________________________
>
>
>