A brief history of Protopasta metal 3D printing filament
Yes, you can print with metal on your filament 3D printer! Protopasta introduced Stainless Steel and Iron PLA filament in 2014. That's 10+ years of metal filament for 3D printing.
We chose stainless steel for polishing and iron for rusting. Also, iron is ferromagnetic! We added steel at 60% and iron at 45% by weight. The result is still novel today.
We later added 60% copper, brass, and bronze to HTPLA starting in 2018. These can be polished or patinaed. They can also be used as-printed or heat treated for high temperature resistance up to 150 C.
Most recently, in January 2025's EX6, we added color (blue, burgundy, and gold) to Steel PLA and switched from 300 to 400-series stainless. Switching to 400-series removes nickel (a prop 65 listed material) and adds ferromagnetism for a more safe and functional filament.
You can find all of our metal filaments here.
Maximizing metal content without sacrificing printability
Now (2025) both Iron and Stainless Steel are ferromagnetic. These magnetic properties are an attractive attribute, literally. For EX10, we set out to increase performance by adding more metal and starting with an HTPLA base. We wondered, "Can we load high enough for sintering?" The answer is maybe, but at great sacrifice to printability.
We prototyped loadings up to 80%, but the filament became extremely brittle, too brittle for reliable 3D printing. So we dialed back the loading to 70% for stainless steel and 60% for iron. That's still more than the previous 60% and 45% for steel and iron, respectively.
Measured improvement with 2x the magnetism + higher temp resistance
The required force to pull these new metal HTPLA composites away from a magnet is about double our original Iron PLA with 45% loading. While sintering for 100% metal strength and density is not recommended, heat treating can increase temperature resistance from 50 to 150 C. There is an associated shrink. See table below with these and other characteristics.
The increased magnetic attraction plus the added heat treatability of HTPLA unlock new capability for stainless steel and iron filaments. Not having to sinter to get some metal properties is a huge benefit.
Introducing Protopasta High Density Stainless Steel and Iron HTPLAs
Please enjoy our higher density options for stainless steel (70 wt%) and iron (60 wt%) in HTPLA for increase increased magnetism, weight, and high temperature resistance! For some test prints, Dustin chose models by Eric Harrell from Thingiverse to 3D print.
Polish or patina? Why not both??? What will you make? Tag Protopasta to show us!
About Protopasta
Protopasta is 100% made in the USA by Protoplant Inc. Founded in 2013 by engineers, Dustin and Aaron Cram, we control every step of the process with in-house made machinery and materials. We’re a small team with a passion for making things, just like you! We’re here because of you. We’re here for you. We thank you for choosing Protopasta!!!
3D Printing High Density Stainless Steel and Iron HTPLA
We 3D printed both at 200C for a good surface finish and layer adhesion at volume rates up to 24 mm3/s on the Bambu P1S with a 0.4 steel nozzle.
Finishing High Density Stainless Steel and Iron HTPLA
For more about finishing metal prints, see our blog on the subject: https://proto-pasta.com/blogs/how-to/polish-or-patina-for-a-real-metal-finish
Heat treating HTPLA
Heat an HTPLA 3D print at 100 C (200-225 F) for 10+ minutes and it’s more heat resistant! Heat resistant up to 150 C (300 F)!!! Heat resistance, the ability to hold shape and load at a temperature, depends on the material and conditions. Heat deflection temperature (HDT) measures stiffness in specific conditions.
HTPLA is semi-crystalline, but becomes more crystalline when heated above its glass transition temperature (Tg). More crystallinity = more heat resistance. Crystallinity is maintained until the material melts. Once melted, the material is reset and must be heat treated again. Printing melts the material so you have to heat treat after 3D printing.
Heat treating must be done above Tg and below melting (Tm). Make sure your oven is preheated with no glowing coils to avoid overheating. Visit our blog for past entries for heat treating methods and results.
For a more exacting shrinkage calculation, measure your specific object before and after heat treating using your specific heat treating conditions.
Missed out on September's Endless Exploration? Get High Density Stainless Steel and Iron HTPLA at Protopasta.com starting in October and/or subscribe to our next Endless Exploration by October 31st for our November shipment (materials TBD).
Take care and enjoy the pasta,
Alex and the Protopasta Team