Sulaiman wrote ...

any steel near your primary will get surprisingly hot, better to use nylon screws/nuts or adhesives.

Hydron wrote ...

I used nylon bolts for everything near the primary, but I suspect that small screw for primary supports etc are fine.

Check out Hi-Q components ( for nylon bolts etc, I got M4, M5 and M12 (!!) bolts and nuts from them for reasonable prices.
The M12 especially were useful for securing end-caps etc, and I also used them to rig up a secondary height adjustment system to allowing coupling to be changed (though I'd probably skip that next time, too much work for little benefit). Note that the M12 bolt price is cheap (not much more than a buck a pop) up to a certain length, then gets much more expensive, at least when I ordered mine.

Antonio wrote ...

There is no need to seal the coil for electrical reasons. A breakdown along the coil would prefer to occur at the outer side, close to the wires, not inside. Closed ends may simplify the assembly, but it's enough to make two plugs, one below where to fix the coil and another above, to fix the terminal. It may be a good idea to avoid metal screws, but at not insane power levels I doubt that they can cause any problem.