At 09:37 PM 12/6/2006, Michael Tope wrote:
>----- Original Message ----- From: "Jim Lux" <email@example.com>
>>>I use black PVC as coil forms at 1200 watts on 160
>>>with no problems.
>>Black PVC, or is it ABS DWV (drain, waste, vent), which is actually
>>a foam core, and even lower effective dielectric
>>constant. Although, being black, and pigmented with carbon, and
>>foam cored, it makes a terrible insulator for HV use, particularly
>>in electrostatic machines. But at the voltages you're likely to
>>see in an antenna system, it should be fine. But in something like
>>a Van deGraaff generator with a few microamps at 500 kV, it is horrible.
>Solid Black PVC, not ABS DWV. My scientific material selection
>process - found some laying on a shelf in the garage when I decided
>to make the coils.
So you use the same technique as I use.. use what's laying around,
and if it catches fire, see if you can figure out what went
wrong. (That's how I found out about the amazingly wide use of
carbon black as a pigment.. It's something I knew, if someone had
asked, but I never connected it to the electrical properties of paint
and plastic pipe until I had some exciting experiences).
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