ptfe are prepared by extruding emulsion fine powder ptfe mixed with an extrusion aid usually an organic solvent or hydrocarbon by any of many methods well known in the art removing the extrusion aid by art methods then stretching or expanding the strand by a method disclosed in any one of u s pat nos 3 953 566 3 962 153 4 096 227 or 4 187 390 to give a highly stretched porous unsintered soft strand suitable for insulating an electric conductor tape 3 for winding about strands 2 is similarly manufactured by extrusion calandering and stretching according to the above methods which are hereby incorporated by reference the resulting process is a high speed process very economical in production of long lengths of cable with minimal scrap the electrical and physical characteristics are both excellent for such a simple product produced by such a simple process which changes the physical structure from that of several separate pieces of material to a unitary mass of considerable mechanical integrity the dielectric or insulation having been converted from a soft unstable material to a stable relatively much tougher stronger material a uniform dielectric constant for the cable or construction is thus insured following the above process the resulting cable.