Polish or patina for a real metal finish

Protopasta Metals are made with real metal powder, but print similarly to standard PLA (for extended use, select a wear resistant nozzle). They print with a cast look (as seen above, L to R, with Iron, Steel, Brass, Bronze, and Copper), but some extra finishing can transform your matte print into so much more (as seen in the same order below).

The idea is not new. In fact, we announced Iron and Stainless Steel only months after delivering on our first Kickstarter in 2014. Iron was designed for rusting and Stainless Steel for polishing. It took a few years before we added Brass, Bronze, and Copper which polish or oxidize as seen below with Brass, Bronze, and Copper with polished and oxidized side-by-side from left to right.

The recommended methods for polishing and oxidizing have evolved over the years. Here are my current polishing and oxidizing recommendations:

I prefer polishing with 3M polishing paper. You can first sand away layer lines with locally available 1XX-2XX sand paper before moving on to the kit's 400-grit. I recommend stopping shy of 8000-grit. I find that 6000-grit gives peak polish. Each time I switch grits, I sand/polish perpendicular to the previous grit to make sure the previous sanding/polishing marks are removed before moving on to the next grit.

I oxidize with a mixture of 3 T water, 1 T white vinegar, and 1 tsp salt. I first expose the metal with sandpaper or a wire brush. You can also oxidize a part at any point in the polishing process. Building patina, much like polishing, takes patience. To oxidize, wet the surface, let dry, and repeat. Using a spray bottle to mist water helps avoid drips to build oxidation without also washing it away.

Want to try your hand at replicating our work? Print yourself an icosahedron, modeled in Tinkercad, for example. For some extra fun, mash up polishing and oxidizing or add some paint with strategically exposed metal for a unique weathered look.

Whatever your technique, we hope you enjoy making valuable, cherished prints for yourself and your family, friends, or business. Don't forget to share your beautiful creations with the world!
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