Pre-finishing Platinum

After filing the added piece to match the shank dimensions, begin with the smoothest grade of abrasive to remove the file marks. Grades range from 220 (coarse) to 8000 (ultra-fine).

Attempting to pre-finish a ring that’s out of round will cause deformation and/or reduction of overall dimensions. Dimensional retention of proper shank depth and width is important for long-term wear.

Most of the pre-finishing for this ring is completed after the stones have been set. If not careful, excessive pre-finishing could reduce prong dimensions, which can make the stones more likely to fall out of their settings.

It’s important to carefully pre-finish and polish after setting the stones. This practice provides a better finished look.

Note that the sides of the prongs have flat surfaces that intersect with a rounded gallery wire. Careless pre-finishing can cause deformation of the parts and a mismatch between the earrings.

Most of the pre-finishing for these earrings, such as the sides of the prongs, is completed before setting the stones. Excessive pre-finishing can increase the likelihood of stone loss.

Pre-finishing and polishing prior to setting provides easier long-term cleaning of the debris that collects during normal wear.

Remove the cast surface, tool marks and any oxidation left behind from soldering (platinum cobalt alloys only)

Record the width at the 6:00 location where the joint will occur

Also record the depth at the 6:00 location where the joint will occur

Be careful to retain all shaping. On the featured ring, the prongs are flat. They must remain flat as the bezel edges are pre-finished.

Use a variety of pre-finishing tools that fit the contours of the jewellery

These wheels are resilient, hold an edge and generate less heat

When pre-finishing platinum, start with the inner surfaces. As wheels wear and become smaller, they are ideal for use inside a ring.

Identify grades of abrasives on the tool’s shaft. Proper placement allows for quick location of, and access to, the tool needed.

Cross-contamination is one of the biggest problems encountered during the platinum finishing process. So always remove the debris from the piece that has been left behind from coarser grades of materials before moving on to finer grades.

Finer abrasive wheels (1000 grit and higher) leave a semi-polished surface on platinum, making the polishing steps more efficient

This wheel has a flat surface that is ideal for pre-finishing the flat wires of the ring design

For rounded edges or tight sharp areas, abrasive wheels can be shaped using a shaping stone. Here, a knife-edge is being formed onto a wheel that had a flat bottom.

Keep all abrasive tools labelled and organised for more efficient finishing

These materials are fast-cutting, uniform and resin-bonded, and are available plain or with an adhesive polyester film backing

Here, the film is wrapped around flat sticks. It can be used in a variety of pre-finishing applications.

Micro-finishing film is also available in strips and other shapes. It can be custom-fitted for tools that have various applications. This is important for retaining design details and uniformity.

For organisation and efficiency, label the abrasives from coarse to fine. Use them only for platinum.

Here, the film is wrapped around semi-cylindrical sticks for use in a variety of pre-finishing applications

Micro-finishing film that is wrapped around a semi-cylindrical stick is an efficient tool for pre-finishing the inside of a ring