I used some hardwood to create the mold for the counterweights. The wood was only 3/4 of an inch thick so I doubled up the thickness. I screwed the two blocks together then I cut out the form using a jig saw. Next I used a third piece for the bottom of the mold. I drilled through all three pieces and bolted them together. I figured it would be easy to remove the bottom after the lead hardens and I would be able to tap the weight out.