With these heating elements, the current-bearing conductor is sheathed in either silicon, Kapton or micanite.
Silicon, besides being resistant to moisture and many chemicals, is relatively sturdy thanks to its vulcanised composite structure.
Kapton, a material manufactured by the Dupont company, is thin and light and practically transparent as well. It is well suited for use in vacuums due to its chemical and physical durability.
Even micanite is available as a foil, which, though it is not pliable and is only mouldable to a limited extent, can stand very high temperatures.
Since the heating foils are manufactured with an etching technique, very precise and uniform heat distribution can be obtained. These flexible heating elements can be affixed to the objects that are to be heated (plates, containers) using an adhesive film, or they even be attached in the factory via vulcanisation. The fact that they are equipped with a temperature sensor, thermostat or delimiter allows conclusions to be drawn concerning the process temperature, and it also makes for a longer service life of the heating foils.
These flexible heating elements are available in a host of shapes, and they can also be configured in practically any position on the foil by making cuts, perforations or slits.