Warning Scotch 235 black paper tape DON'T USE

5/16/2006 4:19 AM

Dave Stephens

Warning Scotch 235 black paper tape DON'T USE I got two big free sample rolls of this stuff, it looks right, very authentic looking. I wrapped some P90s in it and tonite before I shipped them off ran the pickps through the Extech LCR meter. Something seemed wrong as my 8.2 K coil was reading 7K. I thought uh oh, coil short. The Extech seemed to confirm this as the AC resistance was really high like 28K more than double what it should be. I thought coil short for sure. Unwrapped the tape and before destroying the coil measured the DCR and the inductance, suddenly everything was back where it should be. So I put my ohmeter leads across the tape and it was really conductive, so much that in the pickup range it was reading 2 or 3K. The tape is so conductive shielding the two coil ends with it and wrapping the coil with it actually dropped the pickup from 8+ down to 7K.     This stuff is NOT suitable for wrapping coils. If you use you may get a fairly good DCR reading, my other coil measured OK, but again the AC resistance was way high, you'll get a dulled down muffled pickup. BAD NEWS.     So the search for black paper coil wrapping tape continues for me. The Stew Mac stuff is somewhat acceptable but on exposure to air the adhesive turns real goopy and sticky mess. Looks good but some of it is mildly conductive as well. About all that leaves thats really safe to use is the 3M fabric tape.     Anyone found a good source of black paper tape that works yet? This stuff ain't IT.......Dave