path passes through a first shield 11 located within the intake end of electrostatic coating machine 3 as shown in the figure first shield 11 takes the shape of a hollow cylinder and is slidable back and forth parallel to wire path 18 within bearing 16 in a similar fashion second shield 12 also shaped in the form of a hollow cylinder is located within the outlet end of electrostatic coating machine 3 and can be slid back and forth parallel to wire path 18 within bearing 17 first shield 11 and second shield 12 serve to shield the surface of wire passing through electrostatic coating machine 3 the ac field which is used to attract the insulator introduced into electrostatic coating machine 3 from reservoir 8 only causes insulator to be attracted to an exposed section of the wire this exposed section exists between the two innermost ends of shields 11 and 12 in the event that the exposed section of the wire is to be increased which will cause more insulator to be electrostatically attracted to the wire during a given unit of time shields 11 and 12 can be moved away from each other so as to expose more.