An improved insulated coil for an electrodynamic machine is prepared by wrapping multiple layers of a wide insulative wrapper impregnated with a B-staged resin bonding material around the straight section of the coil, in overlapping contact with a narrow insulative tape impregnated with the identical or a chemically compatible B-staged resin bonding material. The tape is overlapped with the ends of the wide wrapper and the wrapped assembly is then heat and pressure treated to cure the resin impregnate to a permanent, solid set and to form thereby an insulated coil with a continuous, unitary insulative joint between the wrapper and the tape.