INTRODUCTION
Before World War II platinum was the metal of choice for many fine jewelry pieces, especially engagement and wedding rings. Platinum was also used to enhance the beauty of diamonds and other precious gems. Many of the world's greatest diamonds were set in platinum, including the famous Star of Africa in the British Royal Scepter and the beautiful and famous Hope Diamond on display at the Smithsonian Institute in Washington DC. During World War II, platinum was classified as a strategic metal and deemed off limits to jewelry manufacturing, thus losing its market share to the newly developed white gold.

Today platinum is enjoying its renaissance. In the U.S., platinum consumption has risen by over 1500% since 1990. More jewelers are carrying platinum jewelry, and consumers are becoming more aware of the most noble of all metals.

Many jewelers are still turning down platinum repairs because they are not familiar with the metal and fear ruining an expensive piece. For many years platinum jewelry was rarely brought in for repair, as many pieces were estate jewelry and owners feared irrevocable damage. Platinum's popularity has created  the need for trade and consumer education, as more jewelers sell and work with this metal.

WORKING WITH PLATINUM
What does it take to be successful at repairing, customizing and servicing platinum jewelry? First an understanding of properties unique to platinum, and realizing that it is not more difficult to work with, but different than any other metal you may have used in the past. Skilled jewelers should have no difficulty adapting to working with platinum, once they understand the metal's characteristics.   

When platinum is mined, I t is usually found along with its 5 sister metals, also called PGM's Platinum Group Metals. They are Palladium, Osmium, Rhodium, Ruthenium and Iridium.

As with all precious metals, platinum in its pure state is too soft to be used in jewelry. It must be alloyed with another metal to improve its workability.

The most common alloys in the United States are 95%Platinum with 5%Ruthenium or 95%Platinum with 5%Cobalt , 95% platinum with 5% Iridium, and  90%Platinum with 10%Iridium.

Platinum has an extremely high melting point (about 1773C / 3224 F). When soldered, brazed or welded, it becomes white hot. This intense white hot radiation contains UV rays that can harm unprotected eyes.

Never use sunglasses to protect yourself against the rays and white light. Even the densest of sunglasses offer very little protection against UV radiation.  

Platinum can be soldered or welded . Solders and welding procedures are described in detail in the original paper.

WORK SPACE AND TOOLS
Cleanliness is essential when working with platinum. Your work bench, tools and the soldering area should be clean and clutter-free. Sand paper sticks as well as files should be used exclusively for platinum

When heating platinum it can be easily contaminated by other metals. Lower temperature metals will melt into platinum. This can make platinum brittle and unworkable. Once contaminated, refining is the only way to reclaim the platinum.

Be careful when using holding devices such as tweezers, binding wire etc. as they can produce a dark stain contamination on platinum that only heavy abrasives can remove. Use Tungsten tweezers.

Be sure to use a ceramic soldering base to do your soldering and welding Carbon is to be avoided, thus charcoal blocks cannot be used. The torch cannot be run with acetylene gas, as that will contaminate the platinum as well.

For detailed soldering or welding information refer to the original paper.

REPAIR TECHNIQUES

Ring Sizing
There are two ways to size a platinum ring using a torch. One is using the soldering technique, the other using the welding technique.

The welding technique is preferred over soldering, as it makes a seamless connection, which solder does not.

To make a ring one size smaller remove 2.52 mm of the shank and insert a small piece of solder into the cut. Melting that solder will join the ring back together.

To enlarge a ring one size, repeat the above technique, except add 2.52 mm of sizing stock . Usually this can be done with two or three soldering operations.

Sizing with the welding technique is a straight forward operation.

A thin piece of platinum is used as fuel and is melted into the gap, creating the bond. It is far superior then soldering and is the preferred method when possible.

Platinum / Cobalt Alloy
The introduction of 95/5 Platinum Cobalt Alloy has caused some dialog in the industry and raised some questions about just how to handle this metal. As you may or may not know, Pt/Co is slightly magnetic.

When welding or soldering with a torch, the cobalt tends to slightly oxidize. This oxidation can be easily removed by a skilled jeweler.

On the positive side, this great alloy allows for beautiful castings,

as it has a much finer grain and is more "wet" and is thus ideal for casting applications.

Annealing
Annealing is the technique used to re align the grain structure of metal after it has been work-hardened. This will make it soft and workable again. The original paper describes this technique in detail.

Re-tipping
Re-tipping is usually defined as "to rebuild a prong tip with the stone in place"

This definition limits the job as only a few stones can take the heat needed to place a new  tip onto a prong. Retipping a platinum prong with platinum solder will damage any stone. The original paper describes this technique in detail.

Setting Stones
Platinum has the distinction of being called a "dead" metal. This means it has very little or no memory. When a platinum prong is pushed into place, it usually stays without sag or spring .

Because of the metal properties of platinum stone setting can easily be accomplished and stones are very secure. The original paper discusses stone setting in detail.

Chain Repair
Repairing  platinum chains is simpler than repairing gold chain. The high melting point of platinum makes it possible to solder even the finest wires without melt down.

FINISHING
After sizing and setting, you are ready to finish the ring. When platinum is polished properly, it will take on a shine that no other metal can produce. Platinum does not oxidize nor is it affected by atmospheric conditions. This assures a good finish is long lasting. But it takes some effort to achieve maximum results. If platinum is being joined to gold, it is important to finish the platinum section first. Failure to do so will result in over-polishing the gold portion of the piece. Before polishing, all scratches will need to be removed. If you don't do this, you will have polished scratches, as it is difficult to remove them through buffing.

The finishing sequence is described in detail in the original paper

SUMMARY
As platinum jewelry continues to gain market share, nearly every jeweler will have contact with this most precious metal. Education and information about platinum is good business. With minor modifications to a workspace and just a few new  tools to be used exclusively for platinum, any small workshop can perform most routine repairs on platinum. And it is plain to see,  there is no need to fear working with platinum; after all, it is not difficult, just different.

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Basic Platinuim Repair Techniques
Jurgen J. Maerz
Director of Technical Education
Platinum Guild International USA

This is an abbreviated version of the original work. For full technical details, please consult the original paper.