Method for the manufacture of a mold for centrifugal casting tubular metal articles

Claim 1

IN A METHOD OF CENTRIFUGALLY CASTING HOLLOW METAL ARTICLES IN WHICH A METAL MOLD PREHEATED TO ABOUT 200 TO 300*C. IS SLOWLY ROTATED AT A SPEED OF 30 TO 90 R.P.M. IN A HORIZONTAL POSITION AND A MIXTURE OF REFRACTORY PARTICLES AND A THERMOSETTING SYNTHETIC RESIN IS INSERTED INTO THE PREHEATED MOLD TO PRODUCE THE FIRST LINING AND THEREAFTER, WHILE THE MOLD IS STILL BEING ROTATED A SLURRY OF REFRACTORY PARTICLES IS INSERTED INTO THE MOLD TO FORM THE SECOND LINING, THE METAL MOLD IS THAN ROTATED AT A HIGH SPEED OF 200 TO 800 R.P.M. AND THE SECOND LINING IS THEN DRIED, THE IMPROVEMENT IN WHICH THE SLURRY INSERTED TO FORM THE SECOND LINING CONSISTS OF A MIXTURE OF 20 PARTS BY WEIGHT OF REFRACTORY PARTICLES WHCH WILL PASS A 150 MESH, 30 PARTS BY WEIGHT OF REFRACTORY PARTICLES WHICH WILL PASS A 270 MESH, 5 TO 15 PARTS BY WEIGHT OF BENTONILE, AND 50 TO 100 PARTS BY WEIGHT OF WATER.