Method of making smooth surface castings of foam metal

Claim 1

THE PROCESS OF MAKING AN ARTICLE COMPRISING METAL FOAM HAVING A SPECIFIC GRAVITY OF LESS THAN 1 AND HAVING COMPLETELY ENCLOSED CELLS DISTRIBUTED THERETHROUGH OF MAXIMUM DIMENSION FROM .002 INCH TO 1 INCH AND HAVING A SMOOTH SOLID NON-CELLULAR LAYER OF MATERIAL ON AT LEAST ONE OF ITS SURFACES COMPRISING PROVIDING A MOLTEN FOAMABLE MIXTURE OF METAL AND A SUBSTANCE WHICH WHEN HEATED PROVIDES A GAS WHICH ACTS TO PROVIDE CLOSED CELLS IN SAID METAL, PROVIDING A MOLD HAVING DISPOSED ON ITS BOTTOM PORTION A LIQUID LAYER, INTRODUCING SAID MOLTEN MIXTURE WHILE SUBSTANTIALLY UNFOAMED INTO SAID MOLD DIRECTLY ON TOP OF THE LIQUID LAYER, FOAMING SAID MOLTEN MIXTURE IN SAID MOLD SUBSTANTIALLY AFTER THE INTRODUCTION OF SAID MOLTEN MIXTURE INTO SAID MOLD AND WHILE SAID MIXTURE IS IN CONTACT WITH SAID LIQUID, SAID LIQUID BEING ONE WHICH MELTS BELOW THE MOLTEN TEMPERATURE OF THE METAL TO BE FOAMED, HAS A HIGHER SPECIFIC GRAVITY THAN THE METAL TO BE FOAMED, DOES NOT REACT DELETERIOUSLY WITH THE METAL TO BE FOAMED, AND DOES NOT SUBSTANTIALLY DISSOLVE ANY PORTION OF THE METAL TO BE FOAMED SAID LIQUID LAYER HAVING AN UPPER SURFACE, SAID UPPER SURFACE PROVIDING A MOLD SURFACE AGAINST WHICH THE LOWER SURFACE OF THE FOAMED METAL BODY IS FORMED, SAID LIQUID LAYER AND SAID FOAMED MATERIAL BEING NONADHERENT, SAID LIQUID LAYER REMAINING LIQUID AFTER SAID FOAMING IS COMPLETED, SAID FOAMED BODY CHARACTERIZED BY A SMOOTH SOLID NON-CELLULAR LAYER OF THE METAL OF THE FOAMING MIXTURE BEING FORMED IN CONTACT WITH SAID LIQUID LAYER.