A photo of the copper infused PLA printed Benchy before the oxidization process.
What if your 3D prints could age like ancient artifacts? That was the question I asked myself when I got my hands on a spool of copper-infused PLA. Unlike ordinary plastic filaments, this one behaves a little more like metal: it shines, it scratches differently, and, best of all, it rusts.
With a little kitchen chemistry (just vinegar and table salt), I discovered that you can accelerate corrosion and grow that gorgeous blue-green patina we usually see on old copper roofs or statues. Suddenly, a simple 3D Benchy boat looked like it had been dredged up from a shipwreck… or stolen from a galaxy far, far away.
The Secret Weapon: A New Nozzle
During the submersion, the copper failed to oxidize in the vinegar and salt solution because there was no oxygen available.
Before the fun part (corroding things), there’s the practical problem: copper filament is brutal on regular brass nozzles. They get chewed up fast, and I didn’t want to spend my weekends endlessly recalibrating.
So, I splurged on an E3D V6 1.75mm Nozzle, a hardened steel nozzle disguised as brass in its heat performance. At $21, it wasn’t exactly cheap, but it meant I could use a variety of filaments, including abrasive ones, without damaging the nozzle. So I can still print fast, but will have less maintenance. In other words, more time experimenting, less time swearing at the printer.
Painting with Chemistry
The 3D Benchy boat after (correctly) using a spray bottle (vinegar, water, salt) to initiate the oxidization process.
I started with the classic test print: a 3DBenchy boat.
I mixed up my “magic potion”, vinegar plus salt until it wouldn’t dissolve anymore. I submerged the boat in the solution and left it for two days and… nothing happened. I realized that oxidation requires air. So I set it on a tray and sprayed the boat every couple of hours with a cheap misting bottle. A bit of oxidation occurred but it was underwhelming. I experimented and used 220 grit sandpaper to smooth some edges and surfaces of the benchy. I gave it the same corrosion treatment, and waited. Within hours, tiny blue crystals nucleated across its surface like frost on glass. My theory is that sanding exposed more of the copper embedded in the PLA material. Now, each cost of spray deepened the effect and dried differently depending on where the misted liquid pooled, dripped, or got caught on overhangs.
Slowly, the hull blossomed with patches of turquoise and jade crystals. After four days of experimenting, flipping, spraying, and waiting, I finally had my masterpiece: a lost, sunken ship. The edges shimmered like oxidized jewelry, while the lip of the hull turned into a miniature science experiment in evaporation. It felt like I was less “finishing a print” and more “collaborating with chemistry.”
It looked ancient, precious, and heavy with story. The corrosion process didn’t just coat the print, it transformed it into something that felt alive, growing, and shifting with each spray. Under natural light, the patina was subtle; under LEDs, it glowed like a relic.
Who knew that a bit of vinegar, salt, and patience could turn plastic into treasure?
Final Thoughts
The final look of the 3D Benchy boat after the oxidization process on the copper PLA print.
This project reminded me why I love tinkering: sometimes it’s not about controlling every detail, but about letting the materials surprise you. Copper PLA, a new nozzle, and some kitchen chemistry turned my prints into artifacts that could belong in a museum. And what’s really exciting about this test is that it is another tool the Makerspace has for projects with faculty or students.
And honestly? I’ll never look at table salt the same way again.