The spec, the UV story, the design rules, and where PA612-CF actually wins · cross-checked against the manufacturer's TDS V1.0, written by the team that prints it.
PA612-CF carbon fibre nylon 3D printing service · UK · quoted in 6 hours.
Keeps most of its strength wet, where PA6-CF halves · light, stiff and weatherproof.
Four quick visuals. Start with which material to pick and where PA612-CF works; the engineering detail is at the end if you want it.
Outdoor / UV-exposed CF nylon · fuel-system parts · drone airframes · classic-car bracketry · humid service where PA6-CF gives up
Peak dry stiffness = PA6-CF · driest moisture story = PA12-CF · sustained outdoor UV with optics = ASA / UV-stable PC · UL94 V-0 = PA6-FR / PPS
Copolyamide alternates short (PA6) and long (PA12) chain segments · splits the difference between sibling nylons on moisture and strength. CF aligns with extrusion · drives XY strength + 1.90× anisotropy.
Plan orientation in CAD before slicing · annealing 100°C/16h locks in crystallinity. Wet state anisotropy rises to 2.33× as Z weakens faster than XY.
"James handled the 3D printing for a functional heat resistant component we needed in batch production. He helped dial in the prototype first with their design service, then produced the final batch with really consistent results. Super fast 3D print turnaround and great quality across all the 3D printed parts. Will 100% be coming back."
"We needed a sit-in F1-car for an exhibition to showcase our new racing game. 3D Printing Express took our CAD, optimised it for strength and weight as we had no idea how it all worked! Turned out beautifully. They colour matched the finish and was looking like the real deal. On show day the cockpit ran non-stop, adults and kids jumped in. Multiple visitors asked who built it."
"We ordered a batch of 100 PA-12 parts from 3D Printing Express and could not be happier. Every part arrived consistent, dimensionally accurate, and ready for use straight from the box. The PA-12 gave us the strength and stability we needed for functional testing, with minimal post-processing required. Delivery was on time, communication was excellent, and their QC clearly made a difference."
Engineering-grade strength · 19% stronger than PA12-CF. Drops only 10% to 83 MPa when fully saturated (vs PA6-CF which halves).
High thermal envelope for fuel-system and engine-bay service. Holds 114°C even under 1.8 MPa structural load.
Manufacturer's published claim · 92% tensile strength retained after 1,000 hours UV exposure. Method/standard not specified · presented as a published claim, not an ISO test.
Lowest-density CF engineering nylon on our shelf · below PA12-CF (1.06) and well under PA6-CF (1.17). ~60% lighter than aluminium for the same load path.
The use cases where PA612-CF earns its place · UV-tolerant outdoor CF nylon, fuel-resistant chemistry, room-temperature chamber, and a printable lead time when CNC or moulding can't justify the cost.
Engineering materials are bought on what they can do · sold on what they can't. Pick a different filament if any of these apply to your part.
The 92% UV retention claim is the lead. Plain PA12-CF yellows in a UK season; PA6-CF loses 50% strength when wet. PA612-CF is the engineered answer for a drone that lives on the airfield year-round.
PA612 is the polymer used commercially as the inner layer of multi-layer fuel-line tubing. Engine-bay temperatures, hydrocarbon exposure, vibration · all within the chemistry's design envelope.
For 1970-2000 cars where the original injection-moulded part is no longer available. Fuel/oil resistance + UV tolerance + dimensional stability over decades makes PA612-CF the no-compromise replacement.
Workshop environments that are humid or oily · vinyl-coating lines, paint shops, washdown areas. Where PA6-CF would lose stiffness wet and PA12-CF would bend under heat, PA612-CF holds both.
A side-by-side of the three carbon-fibre engineering nylons most engineers compare. PA612-CF wins on outdoor / humid service; PA12-CF wins on driest dimensional stability; PA6-CF20 wins on peak dry-state stiffness.
PA612-CF values from the manufacturer's PA612-CF15 TDS V1.0 (ISO 527, ISO 75, ISO 178, ISO 1183). PA12-CF and PA6-CF20 values from the same manufacturer's sibling-grade TDSs · PA6-CF20 water-absorption is approximate (PA6 base polymer is the most hygroscopic of the engineering nylons).
| Property | PA612-CF (here) | PA12-CF | PA6-CF20 |
|---|---|---|---|
| Tensile strength XY (dry) | 92 MPa | 77 MPa | 109 MPa |
| Tensile strength XY (wet) | 83 MPa | ~70 MPa | 55 MPa |
| Wet-state tensile retention | 90% | ~90% | 50% |
| Stiffness (Young's modulus, dry) | 5137 MPa | 3311 MPa | 8636 MPa |
| Heat deflection (HDT 0.45) | 175°C | 131°C | 215°C |
| Heat deflection (HDT 1.8) | 114°C | 105°C | ~155°C |
| Equilibrium water absorption | 2.2% | ~1.5% | ~3.5%+ |
| Density (lighter = better) | 1.03 g/cm³ | 1.06 g/cm³ | ~1.13 g/cm³ |
| Heated chamber required? | No · room temp | Preferred | Preferred |
| Anisotropy XY / Z (dry) | 1.90× | 1.48× | ~2.0× |
| UV retention claim | 92% at 1,000h (mfr claim) | Not published | Not published |
| Cost per kg (filament) | £60-110 | £90-130 | £70-110 |
| Best for | Outdoor, fuel-system, humid-service CF nylon | Dry-storage stiffness, large parts, lowest moisture sensitivity | Indoor dry bench-test-hero, peak stiffness |
The other common engineering-nylon process decision. SLS is a different machine entirely · different base polymer, near-isotropic strength, different cost structure. Pick the row that matches your job.
| Property | FDM PA612-CF (here) | SLS PA12 (powder-bed) |
|---|---|---|
| Process | Filament extrusion, layer-by-layer | Powder-bed, laser-sintered |
| Tensile strength XY | 92 MPa | 48 MPa |
| Stiffness (Young's modulus) | 5137 MPa | 1700 MPa |
| Tensile anisotropy XY/Z | 1.90× | ~1.1× (near-isotropic) |
| Elongation at break | 2.6% | ~20% (ductile) |
| HDT @ 0.45 MPa | 175°C | 163°C |
| UV resistance | 92% retention at 1,000h (mfr claim) | Not published · UV-stabilised grades exist |
| Surface finish · as printed | Layer lines visible · sand or paint for smooth | Matte powder-grain finish, uniform |
| Min wall thickness | 1.5 mm structural | 0.7 mm achievable |
| Internal channels / lattices | Limited (support material) | Excellent (powder is the support) |
| Per-part cost · 1-off | Lower | Higher (machine + powder cost) |
| Per-part cost · batch of 100 | Comparable | Lower (efficient bed packing) |
| Best for | Outdoor / UV-exposed CF nylon, fuel-system parts, drone airframes, humid-service brackets | Complex geometry, lattices, near-isotropic strength, batch-of-50+, food-contact certified grades |
This is 3DPE's standard process for PA612-CF · the equipment and the dried-filament discipline are included, no surcharge. Slicer profile and orientation are tuned per part at quote stage.
File or sketch in. We confirm material, orientation, finish, outdoor/humidity exposure.
Engineer reviewed. Lead time + per-unit cost back inside 24 hours.
Wall thickness, anisotropy, fuel/chemical exposure flagged before print.
Filament dried 100°C / 10h pre-print. Hardened steel nozzle. ISO-spec adherence.
100°C / 16h anneal strongly recommended. Sand or 2K paint to spec.
Tracked UK courier, tracking number sent the moment it leaves.
Drying adds 10 hours and annealing adds 24 hours (16h dwell + cooldown) to any of the above. Lead times start when CAD is signed off · CAD round-trips on rev requests can extend the clock.
Outdoor drone-mount bracket for a multispectral camera that spends 8 hours a day in full UK sun, typical RH 70-90%. Weight reduction vs CNC-milled aluminium · the carbon-fibre stiffness held the camera pointing where the flight plan said it should, and the manufacturer's UV story held up against a season's worth of agricultural-field deployment.
PA612-CF is 15% carbon-fibre-reinforced polyamide 6/12 · a long-chain semi-crystalline copolyamide filament reinforced with chopped carbon fibre. The base PA612 polymer is a copolyamide alternating short-chain PA6 and long-chain PA12 segments · used commercially as the inner layer in multi-layer automotive fuel-line tubing for its resistance to petrol, diesel, ethanol-blend fuel, and engine oils. Carbon-fibre at 15 wt% delivers 92 MPa tensile XY dry, 5137 MPa Young's modulus, 175°C HDT at 0.45 MPa, and a density of 1.03 g/cm³ · the lowest of the commodity CF engineering nylons. PA612 sits between PA6 and PA12 on moisture sensitivity · 2.2% equilibrium absorption vs 3.33% PA6 and 1.5% PA12 · so wet-state tensile retention is 90% (vs 50% for PA6-CF). The defining wedge is the manufacturer's published 92% UV strength retention claim after 1,000 hours · the only commodity CF nylon with a real outdoor story.
"PA612-CF is the CF nylon I reach for when the part lives outside or in a workshop without climate control. PA6-CF is stiffer on the bench but loses half its tensile when the humidity climbs · PA12-CF holds dimensions but isn't as strong. PA612-CF splits the difference, holds 90% of dry tensile when fully wet, and is the only commodity CF nylon with a published UV story. The trade is anisotropy · 1.9× XY-to-Z means you really do need to think about orientation before you slice. Get that right and it earns its place outdoors."
Three questions every engineer Googles when picking PA612-CF · the copolyamide chemistry, how 15% carbon fibre changes it, and what the UV claim actually means in service.
PA612 is a copolyamide alternating short-chain PA6 segments (6 carbons between amides · top row) and long-chain PA12 segments (12 carbons between amides · bottom row). Averages ~9 carbons per amide · half the moisture sites of PA6, double of PA12. Tm 210°C, HDT 175°C, equilibrium water 2.2% · sits mathematically between the parent polymers.
15% chopped carbon fibre (~100-200 micron length) aligns along extrusion direction during deposition · drives the 1.90× XY/Z anisotropy ratio. Higher than PA12-CF (1.48×) because the 15% CF loading is denser than PA12-CF's 10%, but lower than PA6-CF20's ~2.0×. Design load paths along XY whenever possible.
PA612-CF retains ~90% tensile XY wet (91.9 → 83.1 MPa per ISO 527, 2.97% moisture content). PA6-CF loses ~53% (115 → 55 MPa) · the PA6 matrix is far more hygroscopic. This is the practical advantage of the long-chain PA612 backbone for outdoor and humid service.
Polyamide 6/12 (PA612, also written PA6/12 or nylon 6,12) is a copolyamide · a single polymer chain that incorporates both PA6 and PA12 repeat units in alternating segments. The 6 refers to the 6-carbon diamine (hexamethylenediamine), the 12 to the 12-carbon diacid (dodecanedioic acid). The result is a chain that alternates short and long segments, splitting the difference between the two parent polymers on every property that matters.
The commercial pedigree is fuel-line tubing. PA612 is the engineering polymer used as the inner layer of multi-layer automotive fuel-line systems specifically because of its resistance to extraction by petrol, diesel, E85 ethanol-blends, and engine oils over decades of service. The same hydrocarbon-resistance carries through to the FDM-printed grade · engine-bay fixturing, fuel-system brackets, and oil-environment service parts inherit the chemistry's pedigree.
Every amide linkage in a nylon chain is a potential hydrogen-bonding site for water molecules. More amides per unit length means more water-attackable sites. PA6 has one amide every 6 carbons (the most). PA12 has one every 12 (the fewest). PA612 averages roughly one amide every 9 carbons · materially fewer than PA6 but more than PA12. The practical result: 2.2% equilibrium water absorption (TDS value) vs 3.33% for PA6 and 1.5% for PA12.
The wet-state property retention follows the same pattern. PA612-CF holds 90% of dry tensile when fully saturated (92 → 83 MPa). PA6-CF20 halves to 50% (109 → 55 MPa). PA12-CF holds dimensions even better but starts from a lower mechanical baseline. PA612-CF is the only commodity CF nylon where high mechanical AND good wet retention coexist.
Our stocked grade is 15% carbon fibre by weight, chopped to short segments (typically 100-200 microns long, not continuous strands). The fibres orient along the print-head direction as the molten filament extrudes. That orientation drives the 1.90× XY/Z anisotropy ratio · XY (in the print plane) inherits the fibre-alignment strength; Z (layer-to-layer) relies on polymer-to-polymer bonding with minimal fibre bridging across layers.
On the UV claim · the manufacturer's product page publishes a 92% tensile strength retention figure after 1,000 hours of UV exposure. This is a real published number on the supplier-side, and the long-chain PA12 segment chemistry in PA612 does support better UV behaviour than PA6. However, the TDS V1.0 does not specify the test method (ISO 4892, ASTM G154, QUV cycle, or otherwise) or the specific exposure conditions. We present this on the page as the manufacturer's published claim rather than as an ISO-tested specification. For mission-critical outdoor specifications, request a 3DPE-printed coupon for third-party accelerated-weathering testing.
Values measured to the ISO standards cited in the right-hand column, on the manufacturer's own injection-moulded test specimens · directly comparable to other engineering thermoplastics.
| Property | XY · print plane | Z · build axis | Wet · XY / Z · post-immersion | Unit | Standard |
|---|---|---|---|---|---|
| Mechanical · dry status | |||||
| Tensile strength | 91.9 | 48.3 | 83.1 / 35.6 | MPa | ISO 527 |
| Young's modulus | 5137 | 2786 | 3991 / 2387 | MPa | ISO 527 |
| Elongation at break | 2.6 | 2.1 | 4.1 / 1.7 | % | ISO 527 |
| Flexural strength | 138.0 | · | 118.1 | MPa | ISO 178 |
| Flexural modulus | 4584 | · | 3888 | MPa | ISO 178 |
| Charpy impact (notched, XY) | 8.1 | · | 7.7 | kJ/m² | ISO 179 |
| Charpy impact (unnotched, XY) | 25.9 | · | · | kJ/m² | ISO 179 · Fiberon PA612-CF15 TDS V1.1 |
| Thermal | |||||
| Heat deflection (HDT @ 0.45 MPa) | 175 | °C | ISO 75 | ||
| Heat deflection (HDT @ 1.8 MPa) | 114 | °C | ISO 75 | ||
| Glass transition temperature (Tg) | Not published in TDS V1.0 · literature 46-70°C for PA612 family | °C | DSC, 10°C/min | ||
| Melting temperature (Tm) | 210 | °C | DSC lab figure · not the print temperature or the in-service softening limit (see HDT/Tg) | ||
| Crystallisation temperature (Tc) | 180 | °C | DSC, 10°C/min | ||
| Decomposition temperature | 446.4 | °C | TGA, 20°C/min | ||
| Physical | |||||
| Density | 1.03 | g/cm³ @ 23°C | ISO 1183 | ||
| Carbon-fibre content | 15 | % by weight | manufacturer spec | ||
| Equilibrium water absorption | 2.2 | % | manufacturer absorption curve | ||
| Melt flow index | 9.9 | g/10min (260°C, 2.16kg) | ISO 1133 | ||
| UL94 flame rating | HB at 1.5mm | · | UL 94 | ||
| Surface resistivity | >10¹² | Ω/sq (insulator) | ANSI ESD S11.11 | ||
| UV strength retention @ 1,000h | 92 (manufacturer claim · method unspecified) | % | Manufacturer product page | ||
| Processing | |||||
| Recommended print temperature | 250-300 | °C | manufacturer spec | ||
| Recommended bed temperature | 40-50 | °C | manufacturer spec | ||
| Chamber requirement | Room temperature (no heated chamber required) | · | manufacturer spec | ||
| Drying conditions | 100°C / 10h before printing | · | manufacturer spec | ||
| Annealing | 100°C / 16h post-print (strongly recommended) | · | manufacturer spec | ||
| Nozzle material | Hardened steel or ruby (brass ~9h life) | · | manufacturer spec | ||
Tensile load > 30 MPa: orient with load in the XY plane (Z bonds are 47% weaker · 48 vs 92 MPa, anisotropy 1.90×). Below 20 MPa, orientation is less critical. Anisotropy rises to 2.33× in wet service.
Sub-1 mm walls can snap cold under load · 0.8 mm is cosmetic only · 1.5 mm or thicker for engineering use. The 15% CF loading is stiffer than 10% CF in PA12-CF · thin walls go brittle faster.
Above 45° from vertical needs support material · plan part orientation to keep critical surfaces support-free.
Tight-tolerance ±0.1 mm achievable on small parts with calibration · ask before finalising CAD.
Removes 0.1-0.3 mm per surface · pre-paint prep or stand-alone hand-feel polish.
Manufacturer states annealing is strongly recommended for PA612-CF15. Anneal IF service temp > 60°C, sustained load, thermal cycling, OR outdoor / humidity service. Costs ~0.6-0.85% shrinkage XY/Z.
Adds 0.05-0.15 mm per surface · sand 800 grit first, primer + topcoat · for colour-matched exterior parts.
Vapour fuses the matrix without flattening exposed carbon · glossy but textured · sand + paint instead.
Every value on this page traces to an ISO test method. We don't quote derived numbers without naming the standard. The UV claim is the only published-but-method-unspecified figure on the page · and we flag it that way.
No offshore subcontracting. Files, prints, and couriers all stay in the UK.
Send three things: peak load (N or MPa), peak service temperature (°C), and outdoor / humidity exposure. our team come back inside 24 hours with material, orientation, and post-process recommendation · if PA12-CF, PA6-CF, ASA, or PEEK fits better, we say so.
our team review every brief before quote. No ticket queue, no account managers.
According to the Fiberon PA612-CF15 TDS, PA612-CF15 reaches Young's modulus 5137 ± 192 MPa (XY) per ISO 527 with HDT 175 °C @ 0.45 MPa and Tm 210 °C · moderate moisture sensitivity (−22% wet stiffness drop).
Two reasons. First, the long-chain PA12 segment in the PA612 copolyamide backbone gives it the same UV-resistance heritage as plain PA12 (better than PA6 or PA66). Second, the manufacturer publishes a 92% strength retention claim after 1,000 hours UV exposure on the carbon-fibre grade · though we note the test method and standard are not specified in the TDS V1.0, so we present this as the manufacturer's published claim rather than as an ISO-tested specification. For service applications that need real outdoor tolerance over months and years, PA612-CF is the only commodity CF nylon with a published UV claim · everything else (PA12-CF, PA6-CF) yellows and embrittles in sustained UK sun.
Yes · density 1.03 g/cm³ vs PA12-CF at 1.06 g/cm³. The TDS V1.0 publishes 1.03 g/cm³ for this specific grade · and the chemistry supports it (15% CF loading at 1.8 g/cm³ raises composite density less than 25% glass-fibre at 2.5 g/cm³ in PA6-GF which is why PA6-GF density is 1.20). Lowest-density CF engineering nylon on our shelf.
PA612-CF wins on strength (92 vs 77 MPa XY tensile dry), stiffness (5137 vs 3311 MPa Young's modulus), HDT (175 vs 131°C at 0.45 MPa), and UV tolerance (manufacturer's 92% retention claim). PA12-CF wins on moisture stability (1.5% vs 2.2% water absorption), anisotropy (1.48× vs 1.90×), and ductility (4% vs 2.6% elongation at break XY). For outdoor and humid service, PA612-CF. For indoor dry-storage parts where ductility matters, PA12-CF.
PA6-CF wins on absolute strength (109 vs 92 MPa XY tensile dry) and HDT (215 vs 175°C at 0.45 MPa). PA612-CF wins on moisture tolerance · PA6-CF loses 50% of its tensile strength wet (109 → 55 MPa) while PA612-CF loses only 10% (92 → 83 MPa). For any application that sees humidity in service, PA612-CF holds dimensions and strength better. PA6-CF is a bench-test hero with a humidity asterisk.
No · the TDS specifies room temperature chamber. PA612-CF prints reliably on a build plate at 40-50°C without enclosure heating · same as PA6-GF. This is the practical advantage vs PA12-CF (typically prefers some chamber heating to suppress warp on large parts) or PC (needs 70-100°C chamber). PA612-CF runs on standard open-frame industrial FDM.
The TDS V1.0 lists Tg as N/A · not separately published for this specific grade. Literature values for PA612 base polymer range from 46°C (polymerprocessing.com) to ~70°C in CF-filled variants. For practical design margin, assume Tg ~50-60°C · loaded parts above this temperature transition from glassy to leathery. HDT at 0.45 MPa is 175°C (3-minute load test) and HDT at 1.8 MPa is 114°C. Sustained load above 90-100°C is a red-line.
Hardened steel or ruby. Carbon-fibre is abrasive · brass nozzle lifetime is ~9 hours per the TDS, same as PA12-CF and PA6-CF. We run hardened steel on every CF print as standard, included in the quote · no surcharge.
Excellent for hydrocarbons · the long-chain PA612 polymer is used commercially as the inner layer of multi-layer fuel-line tubing in modern automotive systems specifically because of its low extractables under petrol, diesel, ethanol-blend fuels, and engine oils. Native pass for fuel chemistry. Limited against acetone, MEK, and strong alkalis. Fails against strong acids, formic acid, chlorinated solvents, and sustained hot water above 80°C.
| Chemical / family | Resistance | Notes |
|---|---|---|
| Petrol / gasoline | Excellent | PA612 commercial fuel-line inner-layer chemistry |
| Diesel | Excellent | Including biodiesel and E85 ethanol-blends |
| Engine oil, gear oil, hydraulic oil | Excellent | All standard service grades |
| Brake fluid (DOT 3 / 4 / 5.1 glycol) | Excellent | DOT 5 silicone also fine |
| Coolant / antifreeze (ethylene glycol) | Excellent | Including diluted service coolant |
| Methanol, ethanol, IPA | Excellent | Cleaning + assembly OK |
| Detergents, soap, weak alkalis | Excellent | Workshop wash-down OK · better than PA6 chemistry |
| Sea water / saline solution | Good | Better than PA6 thanks to long-chain backbone · short-to-medium term immersion |
| Hydrogen peroxide ≤ 6% | Good | Stronger H₂O₂ attacks long-term |
| Acetone | Limited | Surface attack + softening over hours |
| MEK, toluene, xylene | Limited | Brief contact only · no soak |
| Strong alkalis (NaOH > 10%) | Limited | Polymer-chain hydrolysis risk |
| Weak organic acids (acetic, citric) | Limited | Slow attack over weeks |
| Hot water (sustained > 80°C) | Limited | Hydrolysis risk · better than PA6 but worse than PA12 |
| Strong acids (sulphuric, HCl, nitric) | Fails | Polymer chain breakdown |
| Chlorinated solvents long-term (TCE, DCM) | Fails | Solvent crazing + dissolution |
| Phenols | Fails | Strong PA solvent |
| Formic acid | Fails | Industry-standard PA dissolution solvent |
Ratings reflect long-term immersion / sustained exposure. Brief contact (cleaning wipes, splashes) is more forgiving. For mission-critical chemical service, request a 7-day immersion sample before committing the design.
Yes · the TDS strongly recommends 100°C for 16 hours post-print. Annealing relaxes residual print stresses, raises crystallinity, and gains 10-20% tensile and HDT. Causes ~0.85% XY and ~0.6% Z shrinkage (per the manufacturer shrinkage block · 40mm specimen). For load-bearing engineering parts, annealing is the recommended default.
Standard PA612-CF15 is rated UL94 HB at 1.5mm wall · the lowest horizontal-burn rating, but rated. For UL94 V-0 / V-2 self-certification we stock dedicated flame-retardant grades on request, including PA6-FR which is the same base polymer family with a flame-retardant additive package.
No · standard PA612-CF15 is insulative. Surface resistivity is >10¹² Ω/sq per the TDS (rated OL · overload, beyond ESD-safe range). The 15% CF loading sits at the edge of the percolation threshold but is not consistently conductive. For ESD-sensitive applications use PA612-ESD (dedicated anti-static grade in the same base polymer family) or PETG-ESD.
Continuous service: -40 to ~90°C (Tg-limited). Short-term load: up to ~175°C (HDT at 0.45 MPa, 3-minute test). Outdoor: yes, with the manufacturer's 92% UV retention claim and demonstrated humidity tolerance (90% tensile retention wet). Fuel-resistant chemistry. Not for steam autoclave (Tg too low), not for ESD service (insulative), not for live hinges (CF brittleness).
You'll hear back from our team within 24 hours · with material-fit check, ISO-referenced spec, and lead time on every quote.