Professional Jeweler Archive: Professional Setting of a Half-Drilled Round Pearl

September 2001

Professional Bench/Defining Quality


Professional Setting of a Half-Drilled Round Pearl

Knowing how to attach pearls demonstrates another aspect of quality in your shop


Seems like a simple task: Regluing a pearl onto a ring or into a pendant after performing the required service. But if not done professionally, the process can cause the pearl to fall off when the jewelry is worn.

Removing a Half-Drilled Pearl from Jewelry

Most bench jewelers remove a half-drilled pearl before performing work on an article of jewelry. One option is to submerge the jewelry for 24 hours in Attack, a solution that dissolves without damage the epoxies that secure pearls to posts. (Attack is available from most jewelry tool and equipment suppliers.) A faster option is to use heat to break the bond of glue between the pearl and the post. But be careful because the smallest amount of heat can damage the pearl.

Apply a small amount of heat to the ring shank and allow the heat to conduct itself to break the bond of glue that secures the pearl to the post. Some bench jewelers heat the shank directly; others heat a pair of cross-locking tweezers, clamp the tweezers onto the ring and allow the heat to be conducted toward the pearl.

What You Should Find

Once the pearl is removed from the post, you should find:

  • The pearl should be half-drilled. Some are drilled up to 60% of the depth of the total diameter.
  • The post should be as long as the drilled hole is deep.
  • The outside diameter of the post should be slightly smaller than the opening in the pearl.
The pearl and the post should fit together securely.

Variety of Posts

Once you’ve removed the pearl, you may see a post made from two very small-diameter wires twisted together. The outside diameter of the twisted wires is slightly smaller than the diameter of the drilled hole in the pearl. The twist allows space for the epoxy, making it harder for a pearl to slide off. Or you may find a solid wire post that has been notched with wire cutters about every 2 millimeters to increase the area for epoxy.

Setting a Pearl Onto a Post

1. Measure the length and diameter of the post.

2. Clean out the drilled hole using a twist or pearl drill the same size or slightly smaller than the hole. This removes old epoxy and other unwanted material.

Clean the drill hole with a twist drill.

When drilling a new hole, always use a pearl-drill because a twist drill chips the nacre or outside surface of the pearl.)

Pearl drill
Twist drill

3. Measure the depth of the hole by inserting a wire until it stops and then mark the wire at the base of the pearl. Remove the wire and measure from the base to the mark.

Mark depth of drill hole and adjust the post.

4. Compare the length of the wire post on the jewelry to the depth of the drilled hole. If the post is too long, shorten it. If it’s too short or the diameter is smaller than that of the drilled hole, replace it with one that’s appropriately sized.

5. If the post is not two wires twisted together, notch the post every 2mm with wire cutters or an 8/0 saw blade.

6. Mix a small amount of two-part, 24-hour clear epoxy glue. (The 5-minute epoxy glues on the market are water-soluble and should not be used.)

7. Apply a small amount of epoxy to the post, covering at least 90% of its top.

8. Firmly push the half-drilled pearl onto the post and into position.

A secure fit over a twisted wire or notched post and the proper amount of epoxy glue will create a permanent bond between the pearl and the post that will minimize or eliminate future failures.

9. Allow the excess glue to be pushed into the cup-shaped base. If there’s no cup-shaped base, wipe away excess glue.

10. Place in a ring-holding device and let stand for 24 hours. Inspect, clean and prepare for delivery to your customer.

11. Do the job professionally and charge appropriately for your time.

© Copyright 2001 Jewelers of America Inc.
Illustrations by Lainie Mann – Visual Communications

By Mark B. Mann, Director of Trade Programs, Jewelers of America®

The JA® Professional’s Guide to Fine Jewelry Craftsmanship

Setting Half-Drilled Round Pearls

By Mark B. Mann, Director of Trade programs, Jewelers of America®

Professionally Set Half-Drilled Pearl and Post

A. The post is slightly smaller in diameter than the drilled hole in the pearl and is made of twisted wire or solid wire that has been notched.

B. The post is the same length as the depth of the hole drilled into the pearl.

C. Twenty-four-hour clear epoxy glue was used to bond the pearl to the post.

D. There are no abrasions or other types of damage on the pearl from careless workmanship.

Potential Problems to Watch for:

This post is too short and its diameter is too small. The pearl eventually will fall off during normal wear because of a poor fit and bond.

The hole in the pearl isn’t deep enough and the post is too long. There’s no support at the base of the pearl, so the post will bend every time the pearl is bumped during normal wear until it breaks off.

Five-minute epoxy was used to secure the pearl to the post. This type of epoxy is water-soluble and will weaken when the customer washes her hands. Eventually, the bond fails and the pearl detaches.

This pearl was damaged because too much heat was applied in an attempt to break the epoxy’s bond.
© 2001 Jewelers of America Inc.

This information is required for the second level of the JA® Bench Jeweler Certification™ program. For information about the program, call JA at (800) 223-0673 or visit www.jewelers.org. For more bench jeweler education and related information, visit www.jewelersofam.org and click on JA BenchAdvisor.

Illustrations by Lainie Mann – Visual Communications


Copyright © 2001 by Bond Communications