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

It’s important to carefully prefinish 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 prefinishing can cause deformation of parts and a mismatch between the earrings.

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

Prefinishing 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 shapes. On the featured ring, the prongs are flat. They must remain flat as the bezel edges are prefinished.

Use a variety of prefinishing tools that fit the contours of the jewelry

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

When prefinishing 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 clean debris from the piece that is left behind from coarser grades of materials before moving 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 prefinishing 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 labeled and organized for more efficient finishing

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

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

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

Here, the film is wrapped around half-round sticks for use in a variety of prefinishing applications

Microfinishing film that is wrapped around a half-round stick is an efficient tool for prefinishing the inside of a ring