This week we decided to check out the possibility of making some jewelry as gifts using 3D printed models. We noticed an increasing trend of “semi tarnished” necklace pendants in some of Victoria’s “hip” jewelry vendors. With a spool of ColorFabb Bronzefill in house, we investigated the possibility of polishing the surface to make the metal particles shine.
After poking around some forum pages, we decided to try the ColorFabb Learn page on Bronzefill. Here, they prescribe the use of 200-240 grit sandpaper to smooth lines and expose the bronze particles. They also suggest trying steel wool as a means of increasing the sheen further, and a polishing solution to enhance hold the shine.
For our experiment we opted to use increments of sand paper (180, 220, 400, 600, 1500 grit) and finished with a polishing paste for various metals. All of the printers were occupied so we couldn’t print a fresh model in bronze. As an alternative, we found a small box printed in bronze fill amidst some demo prints from when we first brought in the filament. The lid of the box is a small rectangle and we figured it would be easy to polish and would serve well as an indication of the best possible result. We took photos of each step at an angle that we saw the most evident sheen under our desk lamps.
So with our test print and supplies in hand, we got to sanding! First off, we used the 180 grit sand paper. After a minute or two of relatively light sanding, most of the lines began to disappear. Some shiny flecks emerged, but the overall finish was still matte.
Next we hit it with the 220 grit, sanding again for a minute or so. This go round eliminated more print lines and revealed further metal flecks, but again largely matte in finish.
The 400 grit seemed to have little effect on revealing more shine, so we quickly switched to 600, and again noticed little difference. Puzzled by the failed attempt, we started sanding with more pressure and rigor, yielding an evident change in the metallic appearance of the surface. Odds are that a significant change could have also been observed with 400 grit with a little added “elbow grease”.
Moving onto the 1500 grit sand paper and, as with the 600 grit, sanding with conviction, we began to see the metallic finish throughout the piece. Upon sanding along the print lines, we saw more sheen emerge than we could achieve against the “grain.”
Finally, we moved onto the metal polish. Using a soft, clean, and dry cloth we applied some of the paste by thoroughly rubbing the surface. Next we used another section of the cloth (paste free) and buffed the surface. The result seemed to us layman jewelers indistinguishable from real polished bronze.
We intend on trying this process again on some more complicated models to see if we can generate an acceptable shine to pass off as a real tarnished jewelry. Stay tuned for the next attempt in the coming weeks!