950 Palladium Finishing Procedures

This 950 palladium wedding band design was made using CAD/CAM design and model-making technology and features high millgrained edges, textured diagonal grooves, and a highly polished flat surface. The ring was finished from a rough casting using a progressive abrasive system and limited standard polishing techniques. The prefinishing and polishing system featured in this article can also be used after sizing any 950 palladium ring.

1. To begin the process of prefinishing, sanding drums were made using Foredom's drum mandrels and an overlay of 3M's Imperial lapping film. The lapping film is supplied in PSA-backed sheets measuring 8.5 × 11 inches and is 3 mils thick. The drum portion of the mandrel measures 13 mm in length by 12.5 mm in diameter and is made of hard Teflon-like material. The shanks come in two diameters, 1/8 or 1/32 inch. To make the drums, the lapping film was cut into 13 mm strips and the backing removed. The abrasive film was simply wrapped around the drum of the mandrel as shown.
   Tip: 3M's Imperial lapping film can be used wet or dry. It features micrograin particles of high-grade aluminum oxide that's applied through a special coating process. The result is a fine, consistently distributed abrasive surface that leaves an almost burnished look on the metal, rather than the deep indentations characteristic of typical abrasive papers.
2. There are six grits of abrasives in this progressive system. They range from 320 to 8,000 grit. The blue 320 grit shown in this image has removed the majority of grinding marks left by the coarse removal of the casting gates. The abrasive technique requires light pressure between the ring shank and the drum mandrel while using a rounding, back-and-forth motion.
   Tip: Best results in the progressive abrasive technique are achieved by using all grits in the system. Doing so will not only shorten the time required to complete the overall process but also prolong the life of the abrasive film.
3. After the blue 320 grit, the green 400 grit was used, then the yellow 650 grit, leaving a semilustrous abrasion-free surface inside the shank.
4. The light blue 1,200-grit drum is used next. The abrasive drums are stored in a bur holder, making them easily accessible. The holder is numbered correspondingly with the grits, helping to keep them in progressive order.
5. After using the pink (4,000) and lime green (8,000) grits, the inside of the shank is now smooth, with a high luster. No polishing compound was used prior this final prefinishing step, and only the use of rouge will be required to complete the process.
6. With the inside of the ring completed, the sides are next. The same progressive procedure will be used. The abrasive film is cut to fit a standard-size sanding stick, the PSA backing is removed, and the film is applied to the stick.
   Tip: Use cross sanding techniques. Hold the ring so the sanding can be accomplished in one direction and then turn the ring and sand again. Cross sanding techniques ensure flatter surfaces.
7. With both sides of the ring completed, the central flat portion is next. This part of the process begins with burnish filing. The technique of burnish filing calls for a fine-cut file (a No. 6 barrette in this case) to be used with forward and backward motion. Usually, filing is done only in the forward direction to cut and remove metal. By dragging the file backward, the metal is burnished, making it smoother.
8. The width of the ring between the raised millgrain pattern is 8 mm. A sanding stick is custom cut to an 8 mm width and the film is applied.
9. Pink 4,000 grit begins to yield a flat polished surface. There's one more step prior to polishing.
10. The prefinishing is completed with the six-step abrasive film, and the process has taken the metal from granular to a flat luster appearing polished. The band was then polished with white 4,000-grit polishing rouge and followed by using 8,000-grit white rouge. Inside ring polishing buffs were used for polishing the inside of the ring, a medium felt lap was used for the sides, and a medium/hard felt lap was used for the top flat surface between the raised millgrain edges. A loose stitched buff was used to give the 950 palladium its luxurious and unmistakable final bright white luster.

Palladium Alliance International was founded in 2006 and is dedicated to providing palladium-related sales and technical manufacturing support to the industry and consumers. For information about palladium or PAI, visit www.luxurypalladium.com or contact Dawn McCurtain at dmccurtain@luxurypalladium.com or (877) 473-7873.

Mark and Lainie Mann are co-founders of Visual Communications Inc., a company that provides jewelry-manufacturing technical content; professional images; product testing, research, and development; and presentation and publication of shop, bench, and service department emerging technologies. They produce professional and technical articles appearing exclusively in print in JCK magazine, online at www.jckmagazine.com, and at www.ganoksin.com, the Orchid Web site. Mark Mann was formerly the director of certification and trade programs at Jewelers of America and prior to that, director of manufacturing arts at the Gemological Institute of America. For technical information regarding working with palladium, contact Mark B. Mann at mmann@luxurypalladium.com or call (406) 961-4426.