Platinum Cobalt Peg Settings: Installation and Removal

Quality Assurance Benchmarks highlight workmanship of semi-finished and finished jewellery. Learn how to evaluate the quality of replacement platinum cobalt peg settings.

Illustration showing the side view of a platinum solitaire, with diamonds set in the shank

A good peg setting to ring contact starts with slightly countersinking the peg in the mounting

The peg on the setting was fitted to the hole in the ring mounting

Easy plumb platinum solder was used to join the peg setting to the ring mounting. The setting was soldered before the side diamonds were set.

All tool marks were removed from the peg setting prior to installation

There is uniform solder flow between the base of the peg setting and the ring mounting

The peg setting is level and straight. Prongs align with the ring as seen from the side and end views.

All tool marks were removed from the peg setting prior to installation

Joint between the peg and the mounting does not show pitting or excess solder when viewed through the finger hole

Potential Problems and Engineering Features

Consider these points when soldering a platinum peg setting onto a platinum ring mounting

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Countersinking the setting into the ring mounting creates greater surface contact. Closely fitting the components forms a structurally secure joint.

Solder must flow uniformly from inside the ring, up the peg and around the base of the setting. If a soldered peg setting assembly fails, it will cause the setting and the diamond to be lost during normal wear.

Illustration showing the cross-section of a platinum solitaire with diamonds set in the shank where the peg setting is visible

Laser welding the setting into the ring mounting will not properly secure it for long-term wear

Because the laser can only be aimed at visible joints and penetration is minimal, there’s no guarantee of a continuous bond through the assembly. Too often, laser welded peg setting assemblies fail, causing the setting and the diamond to be lost during normal wear.

How-to Video

Installing and removing a platinum cobalt peg setting

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Platinum Solder and Soldering Material Options

Platinum Plumb Solder

In this example, Easy platinum plumb solder was removed from its container and placed on a solder plate, making it ready for use. There is also water on the solder plate. The water helps weigh the solder down so it will not blow away when a torch is applied to the joint.

Unlike other solders used for platinum repair and fabrication, plumb solder contains platinum. There are three main types of platinum plumb solder – Easy, Medium and Hard. Each type contains a different amount of platinum, which affects the melt/flow temperature range: Easy contains about 90% platinum and melts/flows from 1300°C to 1400°C Medium contains about 92.5% platinum and melts/flows from 1400°C to 1500°C Hard contains about 95% platinum and melts/flows from 1500°C to 1600°C

Platinum plumb solder provides a colour match that’s superior to repair solders that do not contain platinum

Platinum soldering works best when a pallion of solder is placed over the joint. Do not heat it into a ball for transfer using a solder pick.

Store platinum plumb solders in dedicated, labelled containers. Leaving them exposed causes contamination.

Platinum ring being soldered on a platinum ceramic soldering block

Because platinum calls for high heat to solder, anneal and work, platinum-specific soldering blocks are required

This high-heat ceramic material block should only be used for platinum soldering projects. Using it with other metals can lead to contamination if it is used with platinum.

The ceramic material is stable. Thermal expansion of the block will be minimal.

The surface of the block is heat-reflective, which helps the heat to intensify sufficiently for the project

Platinum Silica Soldering Block

This platinum soldering block is made of a fused silica material. It will withstand the heat required to work with platinum and will not break down. The hard surface reflects heat back to the piece being soldered or annealed, speeding up the process.

The block is reversible and can be modified to meet specific needs. This technician created slits in the block with diamond wheels. They hold the piece in the desired position.