The coil i built had an odd history, i kinda copied the secondary from plans i attained from information unlimited, but there primary i could never get to work so i made a vertical coild form from plastic scrap from an injection molding company, hot glued them together and put the primary on that and tuned with an alligator clip, i made my caps out of glass from copy machines as i found out the hard way that window glass is not up to par or it had a thin spot or air bubble as it failed as i was showing the system to my assistant principal at the time, shattered the glass where the arc punched though but has a spare cap with me and got it online again, until i was told it was interfering with the PA system in that part of the building.

I have never really had luck with the tapered primary so i have always used a totally vertical primary as in the example on this thread, i find it easier to tune and in my mind seems to have a better coupling as it's the same shape as the secondary. I am still using the same primary that i built in the early 1990's all hand wound. since i have been hoarding 5 pound spools of magnet wire in hopes of a bigger coil in the future, a few years ago at the towns scrap dealer i found 7, 11 pound spools of 20 gauge wire, bought them for 35 each and sold them for about 100 on ebay and kept one for my self, sadly his others where really messed up and not usable. it's hard to find this kind of wire in larger spools. i have other sizes too i just need to inventory them. i love scrounging that place, my main illumination is from a 39 watt metal halide fixture i got from them, i bought 2 39watt and a few 70 some odd watt ones and harvisted enough lamps for the next 20 years and they where free, my guess is they where toxic waste to that place, they where for a track light system in a store they have a nice color temp too, my guess is 4200k .

Now mack to the coil formers, are they nylon or Delrin or some other rigged plastic?

My corning press for black power i made with a Delrin piston. it works very well but the dang piston was around 120 bucks at the time but i viewed it as a safer material then what some other people use. i wish i still worked there, that had oodles of flat nylon and other plastics in the engineer's scrap bin