Place beads on a threading rod and press them about half way down into a platform of modeling clay.

Check the bead alignment by viewing the lines of beads at a low angle. These beads should be a little deeper in the clay. Because the holes in the beads are above the clay now, in the final jig the holes will be too deep in the jig for the threading rods to easily reach.

Carve out troughs between the rows of beads, and put walls around the mold, then pour in wet plaster.

When the plaster has hardened, remove the jig from the mold. When removing the jig, the drier the plaster, the easier it will be to separate the jig from the mold. Also, take advantage of the flexibility of the clay and use a very slight peeling action to move the clay away from the jig starting at one edge and working across. If necessary the plaster can be sculpted with a knife or wire to make passages for the threading rods. Be careful with the jig, plaster is fragile and will break if it is treated roughly.

If the mold is not damaged when the jig is removed, the mold can be used to make another jig.

Note the beads in this mold are lower in the clay than the one pictured above. This is a better mold and produces jigs that are easier to use.