Professional Jeweler Archive: Polishing Platinum

July 2002

Professional Bench/Path To Proficiency/Tool Tips


Polishing Platinum

Consider this progressive finishing and polishing process


We’ve combined the Path to Proficiency and Tool Tips sections of the Professional Bench department this month to bring you detailed information on finishing and polishing a cast platinum ring using a multistep process. This process is demonstrated by Steece Hermanson, JA® Certified Master Bench Jeweler.™

This rough platinum casting started out as a wax carved by Hermanson. Helmut Frye, owner of TechForm Casting Technology in Portland, OR, cast the ring, which is an alloy of 90% platinum and 10% iridium.
Hermanson will set oval and baguette diamonds into the ring after completing the progressive finishing and polishing process.
Hermanson uses Gesswein’s platinum buffing and polishing compounds for the project. There are five grits of compound from 800 to 8000. He uses yellow stitched treated wheels for three of the coarser compounds and non-stitched muslin buffs for the finer ones. He labels and stores all wheels with their corresponding compounds in plastic bags to avoid cross- contamination when not in use. He will use all five compounds for each platinum piece he finishes and polishes.
The progressive process for prefinishing calls for 3M’s Tri-M-Ite polishing paper. He cuts and stacks the paper in abrasive order for general use. Here you see the grits arranged according to coarsest (400, green) to finest (8000, light green).
Hermanson uses 3M’s Microfinishing film affixed to half-round dowel sanding sticks to prefinish the inside of the ring. He attached the Microfinishing film by wrapping and stapling it to the dowels.
He also attaches the 3M Microfinishing film to cut portions of a yard stick. This set-up works well for flat surfaces requiring prefinishing. He labels the half round and flat sticks from one to six, one being the coarsest, and uses each grit through the process.
During the prefinishing process, cross- working enables the highest quality final appearance. For this, Hermanson uses 3M’s Flex Diamond Bands inside rings along with Microfinishing film sticks. The bands come in five mesh grits. The arrow shows where he marks the drum arbor mandrel with the grit of the mesh wheel.
For super fine prefinishing of platinum, Hermanson uses mounted rubberized diamond polishers. These wheels are available from Rio Grande.
The sprue has been removed from the ring. Hermanson’s first prefinishing step is rounding the ring.
After rounding, Hermanson prefinishes a portion of the outside surface using files, Microfinishing film and rubberized abrasive silicone wheels.
Next, he begins to work the inside of the ring. The base of the shank fits into holding indentations he created on his bench pin. He created the small, medium and larger indentations using various burs.
Hermanson supports the shank in a holding indentation on his bench pin and uses Microfinishing film on a half-round dowel to prefinish inside the ring.
To acquire the flattest and best finish inside, Hermanson prefinishes by cross sanding using 3M’s Flex Diamond Bands.
After prefinishing inside the ring, Steece Hermanson returns to prefinishing the outside, starting with a #6 barrette file.
After filing, he works the surface with various grits of Microfinishing film.
Then he cleans the ring and uses platinum tripoli and a small mounted buff to polish inside the ring.
Here he uses Handler’s 62-II Super Sucker Workstation Dust Collector to gather all debris while prepolishing at his bench. The Super Sucker Dust Collector has two filters and a variable speed motor that can be adjusted for the amount of debris being generated and can be run continuously.
Hermanson works the outside surfaces with platinum tripoli and a mounted buffing wheel.
He places the ring in an ultrasonic cleaner and then starts the buffing and polishing process using Gesswein’s 800 polishing compound at the polishing machine.
He continues to work the outside surface with 800 compound. Next he’ll clean the ring in the ultrasonic cleaner and then progress to the next compound.
Here, Hermanson uses the 4,000 compound. Next he’ll use the 6,000 and finally the 8,000 compounds.
The finished mounting.

Finishing and polishing platinum is a requirement in the second level of JA’s Bench Jeweler Certification program. For information about certification, call JA at (800) 223-0673 or visit www.jewelers.org.

For information on the featured polishing compounds, call Gesswein at (203) 366-5400. To learn more about platinum casting services, call Helmut Frye at TechForm Casting Technology, (503) 652-5224. For rubberized mounted diamond polishers, call Rio Grande at (800) 545-6566. For information on Handler’s 62-II Super Sucker Workstation Dust Collector, call Andy Kroungold at Stuller at (800) 877-7777.

– By Mark B. Mann, Director of Trade Programs, Jewelers of America

Featured procedures by JA® Certified Master Bench Jeweler™ Steece Hermanson, Galloway & Moseley, Sumter, SC

Photographs courtesy of Jewelers of America
© 2002 Jewelers of America

Copyright © 2002 by Bond Communications