Award-winning jewelry designer, bench jeweler, and third-generation store owner Lee Krombholz custom made this 950 palladium ring combining his CAD/CAM (computer-aided-design/computer-aided-manufacturing) technology and master-level jewelry manufacturing skills. Custom-designed palladium jewelry is the latest offering of Krombholz Jewelers, which has been in business more than 67 years.
Krombholz says palladium has superior setting characteristics over white gold—similar to platinum—and notes that the transition to working with palladium was not difficult. Initial customer response to the new metal is promising, Krombholz says, adding, “We will definitely be using more palladium, as it opens up a new product category for our store and keeps us at the forefront of the latest jewelry design and manufacturing technology.”
Three-piece ring and setting is an original design by Krombholz, who laid it out using Gemvision Matrix 3D design technology. The CAD file was then converted to a CAM file and used to automatically carve the wax models for these parts. The palladium casting was done by TechForm in Portland, Ore. Laying out the ring with 3D design technology allowed for precise alignment of the pieces and ease of assembly. Krombholz set 1.60 cts. of round diamond-cut sapphires and the 1.53 ct. marquise diamond after assembly and finishing.
After receiving the cast pieces, Krombholz’s metalsmith, Marc Firestone, prefinished and prepolished the pieces in preparation for assembly. He is shown here using a bur to remove the excess portion of the sprue.
After filing and sanding, Firestone used a “ribbon” technique to sand the inaccessible surfaces with emery paper. He used several grits starting with 320. Using progressive grits to prefinish palladium aids in the preparation of the desired shape and finish.
After prefinishing with files and abrasives, Firestone used a split lap to prepolish the flat surfaces of both sides of the shank. He charged the rock-hard split-lap wheel with brown tripoli. Prepolishing palladium designs prior to assembly ensures the finest final edges, shape, and finish.
Firestone used a bowl filled with Heat Barrier from Gesswein to hold the two portions of the shank together for soldering. Heat Barrier is a claylike material that acts as a heat sink, heat shield, or holding material for soldering. When laying out this design, Krombholz placed positive and negative alignment locators on each side of the shank to make fitting and alignment easier prior to soldering. For joining the 950 palladium shank, Firestone used hard palladium solder from Hoover & Strong. After the soldering was completed, he removed the ring shank from the holding compound, washed off the excess, and then touched up the ring. For eye protection when soldering, he used No. 9 welding glasses.
No flux or fire-coat solution is used when soldering palladium. Soldering causes a slight surface oxidation, which is best removed by using a neutral flame (equal amounts of gas and oxygen) or by abrasives. Pickling solutions do not work for oxidation removal.
Safety alert:To avoid eye damage when soldering, use a welding lens that’s rated No. 5 or darker to view the work.
To solder the prong setting in the top portion, Firestone again placed the ring in the holding material. For this procedure, he used hard palladium solder to join the setting to the shank.
After soldering, the ring was prepolished prior to setting.
The sapphires measure 2.25 mm, and each has precisely the same diameter. To start the setting process, Krombholz used a bud bur to open the setting to about 75 percent of the diameter of the sapphire. Next, he used a 90 degree bearing bur (the same size or slightly smaller) to create the bearing for the sapphires. After seating a sapphire in the bearing, Krombholz used a No. 8 round graver with his GraverMax to raise beads. After setting the first sapphires at the top of the mounting, he progressed down each side of the shank. All sapphires were set at the same defined level, and small beads are raised and pushed against the gemstones to hold them in place.
Krombholz then made a small bright cut down each side of the row of sapphires to remove excess metal. He also used a square graver to remove additional metal between the sapphires and to further form the beads.
After this detail was completed, he used a No. 5 beading tool to hand form each bead, giving each one a consistently round appearance.
With all beads formed, Krombholz used a No. 8 millgrain tool to create a beaded line on each side of the sapphires. He used moderate, even pressure to form this pattern.
Prior to setting the center diamond, he used a plating pen to plate the metal between the sapphires with black rhodium. The darkened background will blend the line of gemstones and provide a pleasing contrast and backdrop for the center diamond. He then set the diamond and completed the final polishing.
This series of articles about working with palladium is sponsored by Palladium Alliance International. The information is applicable to bench jewelers, retailers, designers, students, sales professionals, buyers, and any manufacturer working with palladium. It is being presented by JCK magazine as a service to its readers. To learn more about palladium, visit www.luxurypalladium.com. For additional palladium bench or manufacturing information, contact Mark B. Mann, technical consultant for PAI, at firstname.lastname@example.org or (406) 961-4426.