The construction of the machines shown in this site requires some hability with tools, and this hability is the insurance against accidents. Be careful and patient, use adequate protection, and ask more experienced persons for assistance when necessary. Be careful to not deform plastic parts with the heat. Blowing the disks from above, while turning them, is the most effective method. Insulators must be very good.
Acrylic always works well.
PVC tubes are reasonable in dry air. Nylon slowly absorbs humidity and can become quite conductive after some time. The classical material, varnished glass, can also be used, but plastic materials are better. Bare glass is usually too hygroscopic, and works well only in very dry air. The same applies to distances from charged areas in disks to the machine structure.