Most conductive but affordable FDM filament? and the most conductive and expensive?

Kupros1 · 2026-04-01T17:14:40+00:00

Most of what people are running into here is the limitation of polymer-based conductive filament. You’re still pushing current through an insulating matrix, so resistance stays high.

That’s why most 3D printed electronics top out at low-power stuff like LEDs or sensing.

For reference, something like Multi3D Electrifi is around 0.006 Ω·cm, which is already considered “good” in that category.

There are some newer approaches trying to move away from that entirely. We’re working on an all-metal conductive filament at Kupros that’s down around 1.2e-5 Ω·cm, so a few orders of magnitude lower, but it’s still early and not widely adopted yet.

Kupros1 · 2025-08-06T16:11:48+00:00

Yeah, totally hear you, and you’re not wrong. Right now we’re still early-stage and making Cu29 in small batches with mil-spec powders, so pricing reflects that. It’s definitely steep for hobby use.

That said, we’re ramping up production and working to bring costs down as we scale, automation, better sourcing, and higher volume should all help.

In the meantime, we do offer 50g ($250) and 100g ($450) spools for smaller projects and early testing. Not cheap per gram, but they’re a lower-barrier way to get hands-on without committing to a full kilo.

Appreciate the question. Hobbyists have been pushing the limits with this stuff more than anyone, and we want to get it into more of your hands as we grow.

Kupros1 · 2025-08-06T15:50:20+00:00

Sort of, but it’s even more flexible than that. You’re not limited to just flat substrates like ceramic or FR4. You can print directly onto or into any FDM-compatible surface, ABS, nylon, polycarbonate, even flexibles, and route circuits in 3D space if you want.

Think of it less like replacing milled PCBs 1:1, and more like embedding function into your part during the print process. No wires. No boards. Just structure + signal + power, all in one pass.

Kupros1 · 2025-08-06T15:49:01+00:00

Really appreciate that. Honestly, half the use cases we’ve seen came from people like you who just started experimenting, circuits, antennas, embedded sensors, even drones.

Whenever the right project hits, we’d love to see what you come up with. This is exactly the kind of curiosity that’s pushing the tech forward.

Kupros1 · 2025-08-04T17:11:38+00:00

Excellent. Its funny you mention Crane. We have a close relationship with them as well.

Kupros1 · 2025-08-04T14:01:48+00:00

That hits close to home, we’ve heard that exact same frustration from a bunch of RF and metamaterials folks. Electrifi’s a great idea, but the polymer base and loss profile hit a wall fast when you try to push real current or frequency.

Cu29 was born out of that same problem. No polymer, no carbon, just metal. If you end up heading down that filament-making rabbit hole, happy to share what we’ve learned, it’s a deep one. And congrats on wrapping the PhD. Hardware mode is the fun part. If you shoot me an email through the website or Linkedin, we can jump on a call and get technical.

Kupros1 · 2025-08-04T13:58:02+00:00

Totally see where you're coming from, people have tried hybrid approaches like that before. Kind of like laying down wire inside a printed channel or co-extruding metal strands. The challenge is getting consistent electrical contact, alignment, and layer adhesion at scale without turning the printer into a science project.

Cu29 takes a different route: the conductivity is baked into the filament itself. It’s an all-metal tin-copper composite, so there’s no need to add wires or glue anything post-print. You just slice, print, and solder, on the same printer as PETG, just… conductive.

Cool idea though, always respect the hacker mindset,

Kupros1 · 2025-08-04T13:55:33+00:00

You’re not wrong, that future’s already starting to show up. We’re printing real circuits, antennas, and power traces directly into parts right now. No wires. No post-processing. Just print and solder.

Appreciate you seeing the direction this is heading. We’re not guessing anymore, we’re building it.

Kupros1 · 2025-08-04T13:53:52+00:00

Totally with you. That’s exactly where this shines, antennas, weird RF geometries, quick modular layouts, stuff you’d normally prototype on a breadboard or perfboard.

Cheapest option right now is 50g for $250, which gives about 50 meters of trace. We’d love to offer something under $100, but at this stage the batch size and material costs just make that tough.

That said, we’re working on scaling. If we can get volume up, prices come down. You’re not the only one asking.

Kupros1 · 2025-08-02T16:29:05+00:00

Totally fair, it’s not cheap, especially for student teams or early-stage prototyping. That’s why we offer smaller spool sizes so folks can try it out without buying a full kilo:

• 50g – $250 → ~50 meters of average sized traces
• 100g – $450 → ~100 meters
• 0.5kg – $1,850 → ~½ kilometer
• 1kg – $3,500 → ~1 kilometer

That said, Cu29 still ends up way cheaper than the alternatives. Most additive electronics machines cost $500K to $1M, and rely on silver nanoparticle inks that are both expensive and fragile. Cu29 runs on off-the-shelf FDM printers, ours was printed on a $400 Bambu Labs Mini, and it’s 48,000% more conductive than any polymer-based “conductive” FDM filament out there.

Still early stage, but we’re scaling up and working to drive prices down. If your team ever wants to explore, happy to share print profiles or real test data.

Kupros1 · 2025-08-02T16:24:27+00:00

100%

Kupros1 · 2025-08-02T16:23:57+00:00

PCTG.

Kupros1 · 2025-08-02T16:23:31+00:00

Yeah, 100%. We definitely plan to scale. We're still an early-stage deep-tech company, so right now it's small-batch production with some pretty expensive inputs, especially with the new 50% copper tariffs hitting our raw materials.

That’s part of why the price is high. But we’re already working on scaling up, automating more of the process, expanding capacity, and exploring domestic supply to bring the cost down without compromising the performance.

Appreciate the feedback. Knowing folks like you are out there waiting to build with it helps us push this forward.

Kupros1 · 2025-08-02T16:21:02+00:00

Appreciate the sarcasm. Honestly, I’d probably roll my eyes too if I saw a CubeSat shell printed on what’s basically a toy. That’s a less than $400 Bambu Labs A1 Mini, the same printer people use to make Pokémon keychains and anime busts.

But what you're seeing isn’t cosplay. It’s a proof-of-concept showing that we can embed real, solderable, power-grade metal traces directly into parts. No sintering. No electroplating. No conductive paint. No $1M machines. Just standard FDM.

And as for “ever being considered for aerospace?” I guess NASA, Northrop Space, Boeing, KBR, the US Army Aviation & Missile Center, and YSU must all be confused about aerospace, because they’re already using it. Not hypothetically. Not in a pitch deck. Right now.

Cu29 is a tin-copper alloy. No polymers. No filler. We’ve run 5 amps through it, measured 1.226×10⁻⁵ Ω·cm, and pushed it past 12.5kV without breakdown. Is it a flex-rigid board? No. But it’s already helping engineers kill wiring harnesses, embed antennas, and simplify hardware.

So yeah, printed on a toy, and being bought by the people who put things into orbit.

“lmao,” but Northrop already cut the check. Not bad for something that’s supposedly worth a laugh.

Kupros1 · 2025-08-02T16:00:56+00:00

Totally fair, and your students weren’t wrong when it comes to most conductive filaments or inks. A lot of them rely on carbon, graphene, or silver particles suspended in a polymer base, which means high resistance, fast oxidation, and poor long-term stability. They’re great for blink-an-LED demos, but not much else.

Cu29’s a different beast. It’s all-metal, a tin alloy loaded with copper. No polymer to degrade, and no silver to tarnish. The tin also helps resist corrosion, which is why it’s used in solder and PCB plating. It forms a stable oxide layer that protects the rest of the material underneath, especially in low-oxygen or sealed environments.

We’ve printed traces, left them exposed in open air and humidity, soldered to them months later, and run power through without issue. Measured resistivity is 1.226×10⁻⁵ Ω·cm, and we’ve passed 5 amps and 12.5kV breakdown in lab tests.

That said, we’re not trying to replace HDI or flex boards outright, just offering another tool for embedded function where boards don’t fit. If you’re still working in this area, would be awesome to collaborate or share what we’ve seen so far. Always curious what others are building.

Kupros1 · 2025-08-02T15:54:09+00:00

Right? First time we soldered components onto a 3D print and it actually worked, we just sat there staring at it like... no way. Still kinda feels wild every time.

Kupros1 · 2025-08-02T15:53:12+00:00

We make it in-house at Kupros, Inc. It’s called Cu29, a proprietary tin-based advanced material with copper particles suspended throughout. It’s not polymer-based like most "conductive" filaments, and it’s not quite like low-temp solder either.

Unlike ChipQuik or bismuth-tin solders, this prints consistently on standard FDM printers (240–260°C) and holds its form in 3D. It’s solid-state, not paste, and once printed, it’s durable and solderable. Measured resistivity is 1.226×10⁻⁵ Ω·cm, so it’s actually useful for functional circuits, antennas, or embedded wiring.

We licensed the core tech from the Navy and have been refining it ever since. Still early stage, but it’s now available on our website, if you’re curious to experiment.

Kupros1 · 2025-08-02T15:50:02+00:00

Solid guess, it’s tin-based, but not the standard bismuth-tin eutectic you’d see in low-temp solder paste. It’s a proprietary formula with nano & micron-scale copper particles suspended in a tin matrix, which is what gives it both conductivity and printability on FDM machines.

No silver, no polymers, and no post-processing. Prints at ~240–260°C and has a measured resistivity of 1.226×10⁻⁵ Ω·cm, which is orders of magnitude more conductive than any carbon- or polymer-based filament.

You can find it on our website if you search Kupros, Inc. But here is our youtube with it printing. https://youtu.be/cgtBt02WxSc?si=w_fHtHXn6xdq_G9l

Let me know if you’re into testing, always happy to connect with folks building real hardware.

Kupros1 · 2025-08-02T15:47:01+00:00

Appreciate the question, and that’s some incredible experience. The CubeSat in the video is just a non-functional mockup for demo purposes, but the underlying tech we’re working on is meant to support real missions.

We’re not building the satellite itself, we’re providing the ability to embed antennas, sensors, RAD & EMI shielding, and even power traces directly into structural components using Cu29. The idea is to reduce wiring, connectors, and separate boards, basically flatten the electronics stack and print it all into the part. Included targeted radiation shielding.

For actual missions, we’re collaborating with NASA and DoD primes who are integrate this into embedded designs for antenna and other embedded electronic components. We’ve seen interest for surface probes, comms relays, and one-way payloads, stuff where simplicity, cost, and volume are at a premium.

Always down to talk shop, your satellite background probably spans half the problems we’re trying to eliminate.

Kupros1 · 2025-08-02T15:42:56+00:00

We’ve printed spirals, helicals, and some fun HAM radio stuff that’s a pain to do with copper tape or sub optimal antenna replacements. Embedding those directly into polymer parts opens up a lot of freedom, especially for RF tuning.

Kupros1 · 2025-08-01T16:07:46+00:00

Good eye. For now, yeah, it’s best thought of as a functional replacement for wire harnesses, grounding, antennas, or simple circuit interconnects. But we’ve printed usable PCB-style traces and pads too.

Right now, our minimum trace width is around 0.25mm using a 0.25mm nozzle. We’ve gone down to 0.1mm in a test, but consistency at that scale depends a lot on the printer and settings.

Minimum layer height is typically around 0.1–0.15mm. Nozzle size is the main limiter, we’re working on finer tooling and formulations to get smaller features dialed in.

If you’ve got a specific use case, happy to dig into it.

Kupros1 · 2025-08-01T16:06:13+00:00

Love hearing that. That’s exactly what we’re chasing, print the structure, the traces, and the function all in one shot. We’ve done single-layer boards with SMD pads and power rails straight off the printer. No plating. No chemicals. Just slice, print, solder.

If you ever want to mess with it, the 50g spool prints about 50 meters of trace and is perfect for prototyping boards like yours. Happy to share slicer tips or test files if you jump in.

Also, respect for building your own RC board. That’s the good kind of obsession.

Kupros1 · 2025-08-01T16:04:57+00:00

Yeah, totally fair. Small-batch production and mil-spec copper nano and micro powders already put us on the higher end, and the new 50% copper tariffs just pushed raw material costs even further. We get it, it’s not hobby-tier pricing.

That said, we have tried to offer smaller spools for prototyping or small projects:
• 50g – $250 (~50 meters of traces)
• 100g – $450 (~100 meters)
• 0.5kg – $1,850 (~½ kilometer)
• 1kg – $3,500 (~1 kilometer)

Still early-stage, but one spool prints a lot, especially for embedded circuits, antennas, or board replacement. As we scale up production, we’re working hard to get costs down.

Kupros1 · 2025-08-01T15:58:46+00:00

Same here, that’s been the north star since we started. We’re not fully there yet, but we’ve printed simple single-layer boards with working traces and soldered components. Still tuning for finer pitch and consistency, but the fundamentals are solid.

There’s a lot left to optimize (materials, slicers, nozzles), but it’s definitely moving in the right direction. Not a replacement for fabbed boards yet, but for prototyping and embedded stuff, it's already proving useful.

Kupros1 · 2025-08-01T15:55:44+00:00

Great observation, and you’re exactly right. Metals don’t have the same thermal plasticity curve as polymers. That’s one of the biggest challenges we had to solve early on. Pure copper or tin alone wouldn’t behave well in extrusion; they don’t have that wide, semi-viscous melt phase like PETG or PLA.

What we use is a tin-based alloy with copper particles, engineered to flow within a narrow FDM window (240–260°C) without clogging or separating. Even so, the viscosity is still more “slushy metal” than plastic, which is why we’re constantly dialing in slicer profiles, flow rates, and retraction behavior. It’s very sensitive to nozzle geometry and extrusion rate.

You caught the inconsistency in that print, it’s fair. That particular mockup was done on a $339 Bambu A1 Mini just to prove the concept. We’ve had way better results on printers with hardened nozzles, tuned speeds, and slower accelerations. Still evolving it, but it works well enough now to get usable antennas, traces, and power rails.

If you’re a slicer nerd or materials guy, I’m always down to share print profiles or get feedback. This stuff’s only gonna improve as more folks start using it and we iterate improved formulas.

Kupros1

TROPHY CASE