Hi.....
When winding my second coil (6" dia), I used a lot of
double sided , thin,3M tape. It held the wire flawlessly
and I had it spaced lengthwise w/ 1/2 in. between strips.
I used Behr "Build 50" epoxy, turning it as it cured, and
after two coats, it came out flawless.No bubbles. Hope
this helps.
Tom Renko (The Amp Man)