Best magnet wire to avoid flashovers

[abstruse1]

Currently I'm winding my FB secondaries with 28 AWG wire in 1/4" wide partitions in HDPE forms.  Altho they do pretty well, they will flash over and die if I push them too hard.  My question is, is there a specific kind of wire/insulation for this task?

[Mads Barnkob]

Currently I'm winding my FB secondaries with 28 AWG wire in 1/4" wide partitions in HDPE forms.  Altho they do pretty well, they will flash over and die if I push them too hard.  My question is, is there a specific kind of wire/insulation for this task?

There is 3 grades of enameled / varnished copper wire or motor winding wire, the thickness of the varnish layer varies with the grade and the diameter of the copper wire. I have a full list of the grades and voltage ratings in the tesla coil secondary coil part of the DRSSTC design guide: https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/secondary-coil/ you have to scroll down a bit or search

[abstruse1]

Wonderful info, Mads!  Thanx.

From what you write re voltage differential/winding suggests my problem may not be too bad.  I have encountered several multi inch long areas on removed wire that have the insulation blown off (or otherwise missing).  I do make a serious effort to impregnate the coils in oil in a vacuum chamber ~28 in./Hg for several hours.  I have even heated the oil to ~200 deg. F while doing this.  Still, I can do better.

My bobbin is 2" in diameter, ~2-1/2" long, with five cuts, 1/4" wide, leaving ~1/4" wall thickness over the ferrite.  With 1,000 turns 28AWG, that leaves slightly over 1/4" of the bobbin standing above the windings.  I'm using UHMW polyethylene.

I've thought about coating the windings with Glyptol as I'm winding, but that may enclose the Glyptol so that it never dries,  which it does via solvent evaporation (heating might force drying).  I don't know how much its dielectric properties would be compromised if it isn't dry.  Any thoughts on this method?

Or I could use a low viscosity two-part epoxy, which would assure setting.

I could cycle the vacuum in the chamber after winding to coax whatever liquid I use to work its way thru the windings.

BTW, I've tested several liquid dielectrics and it's looking like soybean oil may be the best.

As we say in this country, "You da man!"

[MRMILSTAR]

Soybean oil will eventually turn rancid. Its best to stick with mineral oil.

[abstruse1]

I can tell when the soya oil turns rancid.  Makes my popcorn taste bad.