Palladium An introduction UK edition Palladium An Introduction 2 Palladium Technical Manual 950 Palladium, Fancy Colour Sapphires and Diamond Bracelet by Brenda Warburton, Austin & Warburton, Ann Arbor Michigan, USA Johnson Matthey and The Goldsmiths’ Company Assay The content is intended as an important tool for the Office London are pleased to present the first edition of jewellery trade in its introduction to palladium and the Palladium Technical Manual. This guide for working will be of interest in the following areas of expertise: with palladium features important palladium design and manufacturing information in a topic-specific format. • manufacturing jewellers, Included under select topics are palladium projects with • designers, complete project details which serve to illustrate certain • retail jewellers, applications. • trade schools, Throughout this manual, you will also find under the Tech • trade and speciality shops Notes, tips and safety suggestions that offer some insight which handle palladium jewellery, into various palladium working characteristics. • jewellery professionals, The manual focuses on information regarding the • retail store owners and working properties of palladium as they apply to the most • managers and sales personnel commonly encountered tasks in the fabrication and repair of palladium jewellery. Index Palladium An Introduction 3 Index - Why Palladium? - Purity/Hallmarking - Wearability - Workability Introduction - Permanent Whiteness - Features and Benefits - Detection of Palladium - World Palladium Usage - History of Palladium Palladium Design - Characteristics Considerations - A Designer’s Medium - Alloys Alloys - Hardness - Palladium Alloys - Applications - Design and Model Guide - Sprues and the Investment Procedures Casting and Melting - Casting - Torch Casting Palladium Palladium An Introduction 4 - Annealing - Cold Working - Cold Working Precautions - Contamination Handworking - Forging, Shaping and Forming PROJECT: Hand Fabricated Palladium Earrings - Cutting and Filing - Hand Engraving - Eye Protection - Joining Overview - Torch Soldering - Solders PROJECT: Preventing Oxidation PROJECT: Soldering 18ct Yellow Gold and Palladium Bands Together PROJECT: Assembly of Palladium Stock Findings Soldering and Welding - Ring Sizing Overview - Soldering Gold to Palladium PROJECT: Fashioning the Perfect Contrast - Torch Welding - Palladium Laser Welding - Filling Porosity - Minor Assembly - Ring Sizing - Tack-Welding - Fusion-Welding Palladium An Introduction 5 - Pre-finishing Techniques PROJECT: Pre-finishing a Patterned Wedding Band PROJECT: Pre-finishing Necklace Parts PROJECT: Pre-finishing 2 Rings PROJECT: Pre-finishing a Mens Ring PROJECT: Pre-finishing Inside Rings Finishing PROJECT: Pre-finishing a Wide Flat Tapered Ring PROJECT: Burnishing Small Imperfections - Magnetic Finishing - Buffing and Polishing - Polishing Techniques PROJECT: Polishing a Gold and Palladium Pendant - Texturing - Surface Finishes - General Overview PROJECT: Setting Round Brilliant Cut Gemstones in Claws and Partial Bezels PROJECT: Setting Cabochons in Bezels Setting PROJECT: Setting a 5-Stone Palladium Ring PROJECT: Setting Small Diamonds in Grains PROJECT: Channel Setting Diamonds - Unusual Setting Styles Machining Die Striking (Stamping) Refining Glossary Weights and Measures Credits Palladium An Introduction 6 Introduction Why Palladium ? Purity Palladium alloys for jewellery manufacturing have a high purity level. They are primarily alloyed with other platinum group metals, and other metals, to suit a wide variety of manufacturing methods. Design by Lainie Mann, Mann Design Group¹ Palladium (atomic symbol Pd) is a platinum group metal (PGM). It is the lightest (least dense) and has the lowest melting point of the group. Palladium is naturally white, not requiring rhodium plating for use as jewellery. It is malleable and ductile in its pure form, but too soft for jewellery unless alloyed. As an alloy containing 950 parts of palladium for jewellery purposes, it is more “pure” than a white gold alloy, but the additional Design by Scott Kay². Photo courtesy of Scott Kay elements make it harder and more durable in the as-cast condition. Its hardness significantly increases as it is cold Hallmarking worked making it ideal for jewellery, and palladium wears similarly to platinum. Palladium resists oxidation In July 2009 the Hallmarking Act was amended to at ordinary temperatures but will discolour at soldering include palladium into the metals that require hallmarking temperatures, become brittle with careless, excessive alongside the traditionally hallmarked metals of gold, and repeated heating and cooling cycles, and react with silver and platinum. From 1 January 2011 the hallmarking strong acids. One of its characteristics that cause it to be of palladium jewellery became compulsory. sensitive to certain jewellery manufacturing procedures is its ability to absorb considerable amounts of hydrogen Exemption weight and other gases, especially when molten. Palladium articles below 1 gram in weight are exempt from hallmarking. The exemption weight is based on the weight of the precious metal content only, excluding, for example, weight of diamonds, stones etc. In the case of articles consisting of precious metal and base metal, the exemption weight is based on the total metal weight: Design by Scott Kay². Photo courtesy of Scott Kay Index Palladium An Introduction 7 Standards available for hallmarking Appearance of the hallmark The standards available for hallmarking are 500, 950 A legal UK hallmark must comprise three marks: sponsor’s and 999 (parts per thousand). It is expected that 950 will mark, a fineness mark and an assay office mark. These be the most common standard. are termed the ‘compulsory marks’. For palladium, the fineness mark will take the form of the fineness number The solders that are permitted to be used for each contained within three adjoining circles. individual fineness is shown in the table below. Fineness Permitted solder Gold, silver, platinum or palladium (or any combination) with a 500* minimum fineness of Other marks, termed voluntary marks, are also available. 700ppt. Historically, these include a date letter and a traditional fineness symbol, e.g. the crown for gold or the orb for Gold, silver, platinum or palladium (or any platinum. A traditional symbol for palladium is also combination thereof) available. This is the head of Pallas Athena, the Greek 950 with a minimum goddess of war, wisdom and craft. fineness of 700ppt. 999 A typical hallmark for palladium, including a date letter and the traditional symbol is shown below: Sponsor’s mark Traditional symbol Fineness mark Assay office mark Date letter Convention Hallmark A palladium convention hallmark is also available. Palladium finenesses recognised by the International Hallmarking Convention are 500, 950 and 999. The minimum permitted solder under the Convention is 700ppt precious metal content for all finenesses. Index Palladium An Introduction 8 Wearability Permanent Whiteness Design by Scott Kay². Photo courtesy of Scott Kay Design by Tom McLaughlin³. Lennon’s Jewelers 950 palladium has a specific gravity of 11.8., which is similar to white gold (most 14 and 9ct white gold Palladium is naturally white, and does not require alloys are around 12.7) and almost half that of platinum, repeated rhodium plating to keep the finished piece making it very comfortable to wear larger pieces. white during normal wear. Workability Design by Lainie Mann¹. Mann Design Group Palladium is malleable, making it easy to bend, form and manipulate. It has little or no memory, a characteristic conducive to the setting process of gemstones, machine forming and hand fabrication. Index Palladium An Introduction 9 Features and Benefits Detection of Palladium Palladium’s colour is very similar to platinum and it is Jewellery designers and manufacturers are beginning to impossible to detect the difference based solely on this. embrace palladium, and have developed new lines of Palladium can also appear very close in colour to high jewellery products with this metal. Even though palladium nickel white gold or rhodium plated white. This image is a prominent platinum group metal, consumers are shows a palladium sample in the centre, with a non- largely unfamiliar with it. rhodium plated palladium white gold sample to its left and a platinum sample to its right. The lighting conditions Here are some selling points that will help introduce this are ideal and it is easy to see the differences between the desirable metal for sales presentations: white gold and palladium and platinum samples. Rhodium plating would have made all three samples appear similar. The following methods will help determine if an Palladium is a platinum group metal. It does not item is made in palladium. tarnish or lose whiteness when worn. Palladium is naturally white, and therefore does not require repeated rhodium plating to maintain its whiteness. Palladium wears similarly to platinum. As with any piece subjected to daily use, palladium jewellery will show surface wear over time. Surface wear is easily restored by cleaning and re-polishing—a 11 regular practice performed by most retail service Design by Novell departments. For non-destructive testing, iodine can be used to detect the difference between palladium, platinum and white Palladium alloyed for jewellery is mostly 95% pure. gold. Place a drop of it on the cleaned surface of the Common alloy ingredients are ruthenium