It’s nice to have a test piece lying around your workspace to experiment with various finishing, polishing, and burnishing tools and methods.
Finishing a piece refers to the final finish or appearance on the metal’s surface and results in the piece looking flat matte, satin, or mirror shiny. Some pieces have a combination of two or three finishes. A matte finish results from tiny scratches in the metal, trapping reflected light and creating a dull appearance. Shiny metal is scratch free, resulting in more light reflection and a bright appearance. Polishing is when all traces of scratches and sanding marks are removed and when the remains of oxidization or patina have been removed. A highly polished metal is bright, light, reflective, and shiny. These pieces are the hardest to photograph, as often you can see the camera lens’ reflection on the piece.
Finishing and polishing can be performed by hand or by using tools on a flexible shaft. The more abrasive the sanding papers and sponges or flexible shaft tools, the more matte the finish. By using progressively finer sanding tools (higher grits), the scratches are removed and a shine results.
Below are two lists for tools to get you started on finishing and polishing, for hand and flexible shaft tools. While some of these can be used on dry-clay pieces, this list is intended for metal-clay pieces that have been fired and perhaps patinaed. You can try many of these, then likely determine your favorites and stick with those.
3M Sanding Sponges
Soft Touch Sanding Pads
Soft Sander Ovals
Fine Sanding Sheets
3M Utility Emery Cloth Sheets
Grits are typically 400-grit (30 microns), 600-grit (15 microns), 1200-grit (9 microns), 4000-grit (3 microns), 6000-grit (2 microns), 8000-grit (1 micron)
Flexible Shaft Tools
Silicone Polishing Discs, Wheels, Pins
Radial Bristle Discs
Grits are typically 36-grit, 50-grit, 80-grit, 120-grit, 220-grit, 400-grit, pumice, 6 micron, 1 micron
Snap On Sanding Discs
Polishing Compounds with Miniature Felt, Chamois, Buffing Wheels
Burnishing is most often done by hand with an agate or steel burnisher or any object harder than silver. The more compressed the surface silver molecules, the more reflective, bright, and shiny the piece. A burnisher greatly compresses the metal’s surface molecules and results in a shine. The only issue with hand burnishing is that the tool leaves indents with each stroke; therefore, you will want to burnish small areas only. Small areas include edges, raised textures, stripes of syringe. Burnishing also occurs by the steel shot in rotary or vibratory tumblers. You perhaps have noticed the longer you tumble, the shinier your piece?
Polishing and Burnishing: https://pmcconnection.com/tools/polishing-burnishing.htmlKris Kramer:
Kris’ home and studio are in Whitefish, Montana. Kris is a certified Precious Metal Clay (PMC) instructor at PMC Connection. She has taught metal clay classes at a community college, at art centers across the country, and out of her studio. Now her teaching presence is online at I Love Silver, which one can access via her website, kriskramer.com. Also at kriskramer.com is a video showing Kris’ art process, access to Kris’ Etsy shop, and lots of free information for all metal clay artists. Link for her page at PMCC: About the Author: https://pmcconnection.com/education/teachers/kris_kramer
“Metal Clay 101” is a monthly series of articles written by the teachers at PMC Connection.