Printable Mold for Casting Lead Milling Balls

grabcad

Positive model for printing and encasing in plaster/sand/whatever you like to create a lead ball mold. The CAD files are for the version I currently use, which is designed to drop into a standard 8oz disposable coffee cup, which serves as the walls of the mold. I've also included stl files for older versions. Easy and fast lead casting. I use regular plaster of paris with some fine sand for the mold and the negative is printed in either PLA or Polymaker Polycast. No supports needed. Melt out the plastic, burn out any remnants, drop in your lead then chuck it in a bucket of water to break up the plaster. Cut off the sprue and runners and you've got some nice non-sparking milling balls. I've found this method much less of a pain than multiple part molds for this particular purpose. The volume of plaster needed for one mold is ~350 mL and the pour uses ~1kg of lead.