Professional Jeweler Archive: Prefinishing Gold Jewelry

March 2001

For Your Staff: Defining Quality


Prefinishing Gold Jewelry

When you take the time to properly finish a piece of gold jewelry, you'll find the final steps go much more smoothly


Which of these two jewelry items is more appealing to you? Which will sell first?

A world-class design that’s finished poorly.
An average design finished to perfection.

Nine out of 10 times, it’s the latter. This article offers tips to help you obtain the best quality when you prefinish a piece of jewelry. When a piece of jewelry is properly prefinished, the final polishing steps are a snap.

In next month’s issue, we will cover polishing techniques for gold jewelry.

 

Tips & Tools for Prefinishing

Covered File Sanding Sticks

To get into very tight, narrow areas, use an old file with abrasive paper attached. Cut the abrasive paper slightly larger than the cutting surface of the file. Clean and degrease the file, use a torch to lightly heat it and then rub a glue stick over the surface. Press the heated file onto the abrasive paper. Allow it to cool, then use a surgical knife to cut the paper to fit – or slightly larger – around the outside edge of the file.

Make several file sanding sticks with different types of abrasive paper and a selection of abrasive grits.

Manicure Sanding Sticks

Fingernail files make outstanding sanding sticks. They’re readily available, come in a variety of grits and have a foam core that makes them ideal to work rounded and domed surfaces.

Abrasive manicure sticks are ideal for rounded shanks and other narrow, curved surfaces. The finer grits are best-suited for jewelry.

Sanding Pads

Another product, the 3M Sponge Sanding Pad,™ is flexible enough to conform to almost any contour, can be trimmed to fit into tight areas, come in a variety of abrasives and can be used wet or dry.

These pads work best for wide rounded or domed surfaces requiring an even finish. They also work well when you turn jewelry on a lathe.

Sanding Boards

To achieve a dead-flat surface, there’s no substitute for sanding boards. The best ones are made of glass cut to the exact size of the abrasive paper. To protect your hands, ask your glass cutter to lightly sand the edges and round the corners.

An old mirror or piece of safety glass a quarter-inch thick works well. Use 3M Super 77 Spray Adhesive™ to attach the abrasive paper to the glass. Make several of these boards with a variety of abrasive grit selections; label them for use with gold, platinum or silver. You can store them conveniently in file folder racks (available from any office supply store).

Label and store your sanding boards in a rack intended for file folders you can purchase at an office supply store.

Sanding Dots

For very small and difficult-to-reach areas, use a hole punch to remove a circle from a sheet of abrasive paper. Glue this dot to the head of a small nail (the head size should be slightly smaller than the dot); insert the nail into your hand-piece. Make several using a variety of papers and abrasives.

This technique lets you prefinish a very small and tight area that would otherwise remain unfinished.

Using Truing Stones to Shape & Renew Abrasive Wheels

Use truing or shaping stones to customize rubberized abrasive wheels so they fit the piece you’re working on. For example, a rounded rubberized abrasive wheel won’t help when you’re prefinishing a flat surface – in fact, it can cause divots in the surface. So flatten the outside edge of the wheel by holding it against the truing stone until it conforms to the exact shape required to perform your work.

Truing or shaping stones are ideal also for removing a “glazed” surface from the wheel and exposing the abrasive.

They come in different abrasive grits and usually are stone, ceramic or a diamond-coated steel block.

Truing a rubberized abrasive wheel using a shaping stone.

Next month we’ll review polishing tips and techniques used in a variety of jewelry finishing applications.

© 2000 Jewelers of America Inc.

– Mark B. Mann, Director of Trade Programs, Jewelers of America
Technical Contributions by Jeffrey Mathews, Jeffrey Mathews Designs, Dallas, TX

Illustrations by Lainie Mann – Visual Communications

 
The JA® Professional’s Guide to Fine Jewelry Craftsmanship

Prefinishing Gold Jewelry

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

Professionally Prefinished Gold Jewelry

A. Flat areas are dead-flat with no indentations, raised sections or obstructions.

B. Corners are prefinished crisp and sharp.

C. The domed surface is even and smooth.

D. The joint between the raised “X” on the domed surface and the surface is even and flat.

E. The original thickness was maintained evenly and has no thick-and-thin areas because of poor prefinishing techniques.

F. There is no loss of dimension or function with the hinge mechanism.

G. There is no loss of detail or function on the closing device.

Potential Problems to Watch for
The divots were caused by using a rounded rubber abrasive wheel on the flat surface. The polishing process will not remove them, but will improve their appearance.
Care wasn’t taken when finishing this flat surface. Using sanding boards allows for a dead-flat finish.
This rounded shank was finished with a flat sanding stick, most likely using short flat strokes. Using a padded sanding stick in curving, sweeping motions will prevent the small flat areas visible here.
This tight area is unfinished but could be accessed and worked by a small barrette needle file with abrasive paper affixed to it.
© 2001 Jewelers of America Inc.

This information is required for all levels of the JA® Certified Bench Jeweler™ program.

For information about the JA® Certified Bench Jeweler™ program, call JA at (800) 223-0673 or visit www.jewelers.org.

Illustrations by Lainie Mann – Visual Communications

Copyright © 2001 by Bond Communications