sparks along secondary

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steven Ward by way of Terry Fritz <twftesla-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

Hi everybody

Does anyone know how to cure those pesky arcs that travel over the entire 
length of the secondary coil??  Ive coated my coil several times with 
acrylic spray, and its helped a little.  My problem is that i use a sphere 
(12" diameter) because its the coolest damn thing ive ever used for a 
topload!  My coil is powered with a 12000v 40ma(modified) NST.  My cap is a 
GE bank for a total of .0136uf at 30000vdc.  I have a 9 gap static gap with 
a blower.  A 9 turn flat spiral primary(12" outer diameter) and an off axis 
tuning inductor.  My secondary is wound on some kind of HDPE (i think) tube 
that is only about 1/32" thick(low losses!).  Its 3" in diameter, and wound 
14" with some 28g magnet wire.  Atop sits a 12" sphere about .5" from the 
windidng.  At times the arcs reach about 30" or so!  This sphere has the 
coolest breakouts ive seen yet.  It takes a few seconds, then WHAMMM!!! a 
huge 28" arc will jump out into the air.  But lately ive been experimenting 
and it seems that it likes to just jump down the side of the secondary coil 
if it cant breakout of the sphere.  Anyone know how to fix this??  Would 
putting plexiglass discs around the coil help??  Ive seen this on big coils 
but not on anything my size.  Any thoughts are welcome,

Thanks,

Steve Ward.