Take a warm ball of Jett Sett (the plastic substitute for shellac)
and place in a 2" X 3" plastic bag. Spread it out to fill the bag
approximately one sixteenth inch thick, then fold the bag in half to
2" X 1 1/2 ". When hardened trim off the top of the bag. Then,
when you have a ring shank or other jewelry that is too thin to hold
tightly, place the jewelry between the two halves of the bag and
insert in your ring clamp.
Brad Simon CMBJ