How to Use Radial Discs for Jewelry Polishing and Finishing

Quick Answer

Use radial discs mounted on a mandrel in a rotary tool, working from coarse to fine grit with light pressure, to polish and finish jewelry in hard-to-reach areas without removing detail.

Step-by-Step Guide to Using Radial Discs

1. Select the appropriate grit and disc size: Assess the surface of your jewelry. Use a coarser grit (e.g., 60-120) for heavy blending and scratch removal, and finer grits (e.g., 6 micron) for final polishing. Choose a disc size that fits your mandrel: 7/8" discs are ideal for small, intricate work, while 3" discs cover larger areas. A common mistake is starting with a grit that is too fine, which wastes time and may not remove existing scratches.
2. Mount the disc securely on a mandrel: Slide the disc onto the mandrel, ensuring the arbor hole fits snugly. Tighten the mandrel screw or chuck to hold the disc firmly. Use the correct mandrel size for your disc: for example, 7/8" discs with a 1/16" arbor require a mandrel that accepts 1/16" shanks (like mandrel 5425). Check that the disc is centered; an off-center disc will vibrate and cause uneven wear.
3. Set your rotary tool to a low-to-medium speed: Attach the mandrel to your rotary tool (e.g., Foredom or flex shaft). Use a speed between 5,000 and 15,000 RPM. Lower speeds offer more control and reduce heat buildup, especially on delicate pieces. A common mistake is using too high a speed, which can cause the disc to load, overheat, and damage the metal.
4. Work with light, even pressure: Hold the tool like a pencil and gently apply the disc to the surface. Let the abrasive do the work—do not press hard. Move the disc in small, controlled circles or back-and-forth motions, following the contours of the piece. Excessive pressure can create flat spots and remove detail; let the tool's weight do the work.
5. Progress through finer grits: After using a coarse grit, clean the piece and switch to a finer grit disc. Continue this sequence until you achieve the desired finish. For a mirror polish, finish with an extra-fine grit like the 6-micron peach disc. Always clean the piece between grit changes to avoid contaminating the finer disc with coarse particles.
6. Inspect your work and clean the piece: After the final pass, inspect the surface under good lighting. If you see scratches or dull spots, you may need to go back to a coarser grit. Once satisfied, clean the jewelry in an ultrasonic cleaner or with a polishing cloth to remove any residue. A common mistake is skipping the final inspection, which can lead to missed imperfections that require re-polishing.

Recommended Radial Discs

• 3" Radial Discs, Unmounted Abrasives, Pack of 12 - Dedeco Sunburst: The Sunburst® 3" TC Discs are high-performance abrasives designed for precision finishing, blending, and polishing a wide range of materials. The 'TC' stands for Thermally Controlled, meaning these discs resist heat buildup during use. The thermally controlled design helps prevent heat damage to your jewelry and the discs, allowing for consistent performance during longer polishing sessions.

  

• 7/8" Radial Discs - Peach 6 Micron (Extra-Fine) 1/16" Arbor (12 pack): The 7/8" Radial Discs in Peach (6 micron, extra-fine) have a 1/16" arbor and are designed for finishing and polishing hard-to-access areas without removing detail or causing flat spots. This extra-fine grit is perfect for the final polishing pass, especially on intricate or textured surfaces where you need to preserve fine details.