Original poster: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx> At 04:10 PM 1/12/2007, you wrote:
Original poster: Gomez Addams <gomezaddams@xxxxxxxxx> On Jan 12, 2007, at 12:07 PM, Tesla list wrote:Original poster: StephenTetorka@xxxxxx Good idea about the water content...still...one sample melted.Pure pvc plastic will absorb plenty of microwaves, it has little to do with metal or water content. PVC has a very high loss tangent at microwave frequencies. Nothing has yet convinced me that PVC's lossiness is significant at Tesla coil frequencies, esp. if thin-walled material is used.
As far as I know, unless the PVC has that black inner carbon coating, its electrical properties will be totally "invisible" at TC frequencies. It is unlikely that PVC will absorb enough water to be noticeable unless you store it in a swimming pool..
There is a new caution with PVC noted by Garry Freemyer. Cheap PVC is often contaminated with bits of metal that can cause shorting if they are near the surface where the wire is. These are black spots inside the plastic.
Before winding, shine a flashlight through the plastic looking for dark shadows like an X-ray. If you find any significant garbage in there, it is probably best to dig it out and patch it with your favorite glue.
Always lightly sand and clean the surface before winding. Cheers, Terry