Electrical members provided with high temperature electrical insulation comprising organopolysiloxanes

Claim 1

IN THE PROCESS OF PREPARING AN ENCAPSULATED ELECTRICAL MEMBER COMPRISING AN ELECTRICAL CONDUCTOR HAVING SOLID INSULATION APPLIED THERETO, SAID MEMBER HAVING INTERSTICES THEREIN AND IRREGULAR SURFACES AND RELATIVELY LARGE APERTURES AND RECESSES OPEN AT THE EXTERIOR THEREOF, THE IMPROVEMENT INCLUDING THE STEPS WHICH COMPRISES (1) SUBSTANTIALLY CLOSING THE APERTURES AND RECESSES WITH A PASTY COMPOSITION AND APPLYING QUANTITIES OF SAID PASTY COMPOSITION ABOUT ANY PROJECTIONS AND SHARP CORNERS WHEREBY A SMOOTHER AND MORE UNIFORM EXTERIOR SURFACE IS PRODUCED ON THE MEMBER, SAID PASTY COMPOSITION CONSISTING ESSENTIALLY OF 5 PARTS BY VOLUME OF A FIBROUS INSULATING MATERIAL, FROM 10 TO 20 PARTS BY VOLUME OF A FINELY DIVIDED INORGANIC SOLID, FROM 10 TO 40 PARTS BY WEIGHT OF A HEAT HARDENABLE ORGANOPOLYSILOXANE BINDER, AND SUFFICIENT VOLATILE SOLVENT TO RENDER THE MIXTURE PASTY WHEREBY OF A HEAT BE APPLIED WITHOUT RUNNING OFF, (2) HEATING THE PASTY COMPOSITION TO DRIVE OFF THE SOLVENT AND HARDEN THE COMPOSITION TO A POROUS SOLID MASS, (3) APPLYING A REMOVABLE PLUG MEMBER TO THE ELECTRICAL MEMBER AT A POINT WHERE THERE ARE APERTURES LEADING TO THE INTERIOR OF THE ELECTRICAL MEMBER, (4) APPLYING A COATING OF A PRIMER SELECTED FROM THE GROUP CONSISTING OF TITANATE AND SILICATE ESTERS TO THE EXTERIOR SURFACE OF ANY METAL PARTS OF THE ELECTRICAL MEM-