Making a 950 Palladium Three-Stone Ring
An introduction to this alloy’s working characteristics

BY MARK B.MANN
TECHNICAL CONTRIBUTIONS BY PAUL PETERSON, PAUL PETERSON CUSTOM JEWELRY, LOS ANGELES, CA

The 950 palladium three-stone ring at left was designed by Lainie Mann using Matrix jewelry design software. The rendering in this image was done by Mann using Matrix. It was cast by Hoover & Strong using their new TruPd™ 950 palladium alloy. The ring contains an oval 2.12-ct. pink tourmaline, two 0.33-ct. round brilliant diamonds, and two 0.15-ct. trillion- shaped sapphires, all set by Paul Peterson of Paul Peterson Custom Jewelry in Los Angeles, CA. The 14k yellow gold trim accents were laser welded prior to the setting.

Several years ago, Peterson made pure palladium (versus 950 palladium) jewelry for a company in Beverly Hills and found it overall to be inferior. He says, “Pure palladium was too soft, responded poorly to burring and graver work because it was gummy and the color was not as bright-white as the 950 TruPd alloy used to make this ring.”

The wax models for the ring and trim pieces were produced by the Gemvision Revo 540A mill. The ring was cast by Hoover & Strong with their new 950 palladium TruPd alloy. The palladium casting was done using platinum casting techniques and materials. Hoover & Strong recommends that induction casting equipment with a sealed melt chamber be used. Ideally the melt chamber should be vacuumed after loading the palladium and then back-filled with argon. The 14-karat yellow gold accents were cast using standard gold casting techniques and materials.

The raw castings with the location indicated of the single sprue used by Hoover & Strong for casting.

The sprue was removed by filing and then the ring was rounded. Here it is being pre-finished using 3M micro-finishing film sanding sticks. Foredom ceramic impregnated rubber abrasive wheels were also used while pre-finishing.

With pre-finishing complete, the ring was tumbled in a magnetic finisher with stainless steel micro pins and a burnishing solution for 15 minutes. Next, the outside surfaces of the ring were sanded using extra fine sanding sticks then rough-polished using Foredom's platinum blue compound, shown here.

The polished 14-karat yellow gold accents were fit to the ring prior to laser welding. Note: When soldering gold to palladium, a cadmium-free solder must be used to form the best joint.

The gemstones were set by Paul Peterson. He started by placing the ring in shellac and setting the trillion sapphires. The shellac was removed and the ring was placed on a mandrel to set the diamond side stones, and then the center stone in the partial bezels. Peterson remarked about how well the alloy performed during the setting procedure stating that, "The bearings were easy to cut precisely with my burs (and lubrication), the metal was malleable and the hammering of the bezels went remarkably smooth. Also, the metal responded well to the graver work required for the bright cuts".