20 lbs. microcrystalline wax
1¼ gal. #10 weight oil
7 lbs. plain automotive grease
50 lbs. gritless dry clay powder (Such as Kentucky ball clay, or Gordon clay)
Works fine. I have done this in a 30 gallon drum over a burner. Once complete pour out onto wet concrete. There are three versions of microcrystalline wax. "Victory Brown," "Amber," and I belive there's a food grade version. In my early life we used "Bandy Black," a coarse grained ball clay. The dark color of the combination of the victory brown and bandy black was a pleasing color for me. mobility of the clay can be changed by warming the room.