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Re: Re New cap



> 
> The initial rise was due to oil, with a higher dielectric constant than
> air, replacing the air between the plates.  Unfortunately, the poly slowly
> absorbs oil and swells, increasing the plate-to-plate distance, reducing
> the capacitance.
> 
> In a rolled poly cap that I just finished, I also noted a similar increase
> when I added (mineral) oil.  However, as the roll was very tight, and a
> tight fit between the inner pipe and outer case, the amount of oil
> between plates was minimal, and any swelling only squeezed out any
> remaining oil, inhibiting further absorbtion, swelling, and capacitance
> loss.
> 
> Gary Lau


  I sort of thought this might be the cause. I wanted to get the opinion
of some more experienced "heads" just to see if my line of reasoning had
any merit. I have seen some compatability charts in the back of the
catalog were I bought the poly. It states mineral oil is a plasticizer
for polyethelene and will cause some slight swelling, and softening to
occur. But will cause no chemical degradation. Thank all of you for your
replies.



                                   Frankensteins Helper
                                          Max