If you look back through his posts he does a real good job explaining how to do it. Basically you cut a brash rod to fit in the cavities of the mold. Shoot your outside color with the brass rod in place. Open mold pull the rods out cut the tails off, and put the hollow baits back in the mold. Then clamp up the mold and shoot whatever color you want the core and tail to be. It's pretty simple once you understand how to do it.