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Re: Glass/poly and more...
---------- Daryl P. Dacko[SMTP:mycrump-at-cris-dot-com]
Sent: Thursday, September 18, 1997 3:15 AM
To: Tesla List
Subject: Re: Glass/poly and more...
At 12:21 AM 9/17/97 -0500, you wrote:
>
>Hmmmm.....
>
>> From: Daryl P. Dacko[SMTP:mycrump-at-cris-dot-com]
>> Sent: Tuesday, September 16, 1997 6:35 AM
>> To: Tesla List
>> Subject: Re: Glass/poly and more...
>>
>> At 05:30 PM 9/15/97 -0500, you wrote:
>> >
>> >A while back , perhaps 5 moths ago, I made a saline cap from
>> >a very tall cylindrical wine bottle (Rene' Junot). The ouside was
>> >wraped in aluminum foil, water sofner salt was poured in to the
>> >shoulder level, then water water added to cover, motor oil filled
>> >the remaining space as a sealant.
<snip>
>> >Next step was AC seasoning with about 5KV for a few hours at a time.
>> >Shortly after it's construction and preping, it measured 680 pf.
>> >I must mention that was never used in TC service, but sat on the basement
>> >floor for those 5 months. Now it reads 1200 pf.
>> >Guess using a wine bottle makes it get better with age. (I'm joking)
>> >
>> >Maybe the copper reacting with the salt is making copper cloride which
>> >lowers the internal resistance and thus the impedance seen by the bridge?
>> >
>> >I know you were looking for oil cap experiences, but I thought I'd throw
>> >this
>> >little experience in the ring anyway.
>> >
>> >Jim M
>>
>> An interesting hypothsis follows:
>>
>> Glass will absorb water, forming a hydrated layer that increases with depth
>> the longer it sits.
>>
>> Water has a very high (I'm on vacation and lost without my books) dieletric
>> constant.
>>
>> It would make sense to me that if glass sat in contact with water, it would
>> make a better cap due to it's dieletric constant increase.
>>
>> Q.E.D
>>
>> Daryl
>
>Unfortunately, water dissolves glass slowly which increases the ionic
>content of the water and makes a less than suitable dielectric.
>
>QED
>Malcolm
Yep, it does dissolve in water slowly - makeing a bad cap into an even worse
one as the lossy effects of a higher dieletric constant make itself known ;'}
I seem to remember that the sodium, potassium and calcium (etc, etc.)
dissolve much faster than the silicon, and this in turn forms an open
lattice holding water and water bound into a 'jelly'.
I suppose it could be a surface area effect too, since most stuff in the world
has more than one cause and effect vector...
I suppose that I should make up a salt water cap and measure it's value
and dissipation factor over a few months, now that my interest is up.
I hope never to go back to salt water caps, but you never know ;'}
Daryl