Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx> There seem to be two kinds of black plastics.One is a greasy carbon filled material that is used to resist UV and other nasty things. It usually makes a black mark on paper like a grease pencil. Often it is used as in internal coating in some types of white pipe seen at the hardware store. This type conducts and shorts under high voltage.
The other type is a dye. It seems to be a very deep purple that looks black. Often hard and shiny. This type seems to resists high voltage like any plastic.
In general, it is best to try and test it with a NST or something to make sure it will not conduct since both types have variations that make it hard to tell for sure just by looking at them.
Of course, green, white, clear... plastics have no carbon in them in any case...
Cheers,
Terry
At 12:49 AM 4/24/2006, you wrote:
The green SDR (sewer & drain) works very well as it's thin-walled for lightweight secondary and, well, . . . . . it's gr-e-e-n!! Megs out very well on our solid state megger. The black doesn't do very well --- might begin conduction at the right potential.Someone also had a question on proper sec coil elevation for both 4 inch ID and 6 inch ID white PVC tubes when used as a sec coilform. Use dual interior baffles --- one 5 inch down from top and one 5 inch up from bottom. Silicone in place with GE Silicone II clear.For 4 inch ID use 1.75" above horizontal plane of primary and for 6 inch use 2.25 inch elevation. Use a 2 x sec coilform dia toroid dia with a min. of 4:1 major dia to min. dia ratio on the toroid. You can also use up to 3x or 4 x if you plan on using a large pri cap and have a lot of driving power available, ie, 180-250 mA. 2 X works great with either 60, 90, 0r 120 mA driving power. With this coupling setup --- No racing sparks --- ever!!Dr. ResonanceAfter burning a nice hole in my secondary I went to home depot to find a piece of pipe for a replacement form. A came home with a hunk 4"x24" of black ABS. I've searched through the archives and have read mixed opinions about black ABS. Someone suggested that rubbing it on paper would be a good test to see if it contains carbon. What I have is very hard and leaves no mark. The other suggestion is to rub in im my hair to see if it generates static. I shave my head, so my shiney head precludes me from running that test! So what do you guys think? Would this stuff be OK, or should I pitch it and get a hunk of white PVC? Are there any other tests I could run? Thanks, Curt.