From PLA to nylon: the filament masterclass

Published · Researched 2026-09-21

A spool of PLA, the default filament.

Filament is the least honest aisle in 3D printing. The spool promises the property; your printer, your dryer, and your enclosure decide whether you get it. Every step up this ladder is really a workflow tax. PLA prints itself. PETG demands a dryer. ABS/ASA demand an enclosure plus fume management. Nylon demands a dryer, an enclosure, a hardened nozzle, and glue. PEEK demands a printer you don't own yet.

Buy the material your setup can run. That's the one-line rule for picking a filament, and it beats every property chart.

Rung 1: PLA — the default, and when to leave it

Start here and stay here longer than your ego wants. PLA prints crisp detail on any machine, needs no enclosure, and smells faintly sweet rather than chemical. It softens around 55 °C, which rules out car dashboards and hot drinks — the part left on a sunny dashboard turns into modern art.

The move from commodity PLA is PLA+ / Tough PLA, not a fancier brand of the same thing. The "+" is a branding label (pioneered by eSUN) for formulations with noticeably higher impact resistance and elongation while printing identically to PLA. A ~140-comment Facebook thread from 2025 reached near-consensus: eSUN PLA+ at ~$16/roll prints like PLA and survives drops that shatter plain PLA. Prices today: Bambu repriced PLA Basic to $15.99/kg on Sept 16, 2026 (bulk down to $12.47/roll) — the cheapest name-brand PLA bought direct. Prusament at $29.99/kg is the "zero surprises" premium, rarely the value pick.

When to leave PLA: parts that take impacts (brackets, mounts), parts that live in heat (cars, gardens), anything load-bearing. PLA's brittleness is its real flaw — it snaps where PETG bends.

The decorative shelf — silk, marble, glow, wood — is PLA wearing costumes, and each costume has a price. Silk PLA is gorgeous and layer-line-hiding but brittle; one Bambu forum thread documents severe layer separation that no amount of drying, slowing, or heating fixed — thin silk parts are display-only. Glow-in-the-dark is genuinely abrasive (eSUN's own page says to use hardened-steel nozzles; the phosphors visibly enlarge brass). Wood-filled needs a 0.5 mm+ nozzle or you'll learn about partial clogs the slow way. None of these are engineering materials; buy them for how they look.

Rung 2: PETG — the functional default

PETG is what you buy when PLA isn't enough but you don't want to reorganize your life. Tougher, better layer adhesion, survives ~70–80 °C service and UV — brackets, mounts, outdoor fixtures, printer parts. No enclosure needed.

The real tradeoff, and the one owners complain about most: PETG is stringier and wetter. Nearly every PETG complaint in the groups — stringing, blobs, rough surfaces — traces to wet filament. Bambu's PETG HF says "must be dried before use" right on the product page; the recipe is 65–75 °C for 8–12 hours, stored under 20% RH, printed from a dry box on long prints. The second complaint: PETG bonds so aggressively to smooth PEI and glass it can rip chunks out on removal — textured plate or glue stick as a release layer, and let the plate cool before prying. (Owner tip worth stealing: one Engineering Filament Lab member chose PETG-CF for a robot arm specifically because they "don't have proper ventilation for abs/asa" — stiffness without the styrene burden. Budget CF grades must be dried first, and Z-impact is weak, so orient parts deliberately.)

Pricing today: Bambu PETG HF at $15.99/kg is the price leader among name brands after the Sept 2026 drop, and owners praise its near-PLA ease at speed. Overture historically undercut everyone (~$14/kg street, bulk under $11) — but those figures are stale crawls, re-verify before bulk-buying. Prusament PETG holds the premium at $29.99.

Rung 3: TPU — flexibility without the misery

A spool of flexible TPU filament.

TPU comes in Shore hardnesses: 95A (shoe-sole firm) up to 85A (rubber-band soft). Phone cases, gaskets, vibration dampers, drone parts, cosplay props — if it should bend, it's TPU.

The misery-avoidance checklist, in order of how much misery each prevents:

1. Dry it. Stringing is the #1 symptom of wet TPU, and TPU is moderately hygroscopic. eSUN says 50–55 °C before sessions; Bambu's 95A HF says 70 °C/8 h. One owner report in the research: brand-new Overture TPU needed 10 hours at 55 °C before it behaved. Never assume a fresh spool is a dry spool.
2. Slow down. 25–40 mm/s for standard 95A; softer grades slower still. Minimize retractions, keep the filament path constrained.
3. Direct drive for anything softer than 95A. Bowden tubes and soft filament jam — MatterHackers is blunt that NinjaFlex on Bowden "requires very specific fine-tuning." Cheetah 95A's low-friction skin makes it the most Bowden-tolerant. Bambu's TPU 95A HF prints up to 200 mm/s but is NOT AMS-compatible; their separate "TPU for AMS" (~68D, stiffer) is the AMS answer.

The price ladder per kg (Sept 2026): eSUN ~$20 < Overture ~$23 < Polymaker PolyFlex TPU95 ~$40 ≈ Bambu TPU 95A HF $41.99 < NinjaFlex ~$108–118. Polymaker is the "reference 95A" for consistency; NinjaTek charges a 3–5× premium for the softest-feeling 85A. One caution from the research: one retailer published a Young's modulus of "33.6 GPa" for a TPU — an implausible unit error for rubber, almost certainly MPa. Read spec sheets skeptically.

Rung 4: ABS and ASA — where the enclosure becomes mandatory

ABS is the classic functional thermoplastic of the RepRap era: strong, ductile, usable around 90–100 °C, acetone-smoothable, and the primary recommended material for Voron builds. ASA is its outdoor twin — same styrene family, same enclosure demands, but the UV-vulnerable rubber phase is replaced with an acrylic elastomer, so it doesn't chalk and embrittle in sunlight. Voron's own materials guide names ABS primary and says ASA is "fully supported" with near-identical properties.

Why the enclosure matters here isn't just warping (though ASA warps hard without one — heated enclosure at 45–60 °C ambient is the Voron norm). It's the styrenics' real gate: fumes. ABS/ASA emit styrene + ethylbenzene VOCs and ultrafines. The community's working consensus is unusually frank: owners report headaches, nausea, and persistent cough from unventilated printing, and the accepted position is that carbon filtration or outdoor ducting is part of the material's cost. An enclosure alone holds the smell in the room — it doesn't touch the danger. And never print styrenics in a bedroom; one FB group member chose PETG-CF for a robot arm specifically because they "don't have proper ventilation for abs/asa." That sentence is the entire material-selection logic in miniature.

ASA has quietly displaced ABS as the Voron-world default for anything that sees sun: slightly less warp, matte finish that hides layer lines, similar price. Polymaker PolyLite ASA at $24.49–26.99/kg (live Sept 20, 2026) is the community's reference spool — and a 31-comment FB debate put ABS's position bluntly: price is the only reason anyone still buys ABS, with owners naming ~$10/kg ASA as their abandonment point. Bambu's ASA at $46.99/kg is the "luxury tax" version — RFID profiles and convenience, not mechanical advantage. ABS lives on at PolyLite's $19.99/kg.

Both need: enclosure (mandatory in practice), ventilation (non-negotiable), glue stick as a release layer on PEI (ABS bonds so hard it can rip the coating off). And one real trap: "ABS+" variants with unknown composition — Voron explicitly rejects them for new builds, because some have a Tg as low as ~75 °C.

Rung 5: nylon — the warping ladder, climbed one rung at a time

Nylon filament, an engineering material with a temper.

Nylon is the engineering workhorse: tough, abrasion-resistant, self-lubricating — gears, bearings, drone parts, jigs. The catch is legendary: PA6 absorbs moisture fast enough that a fresh sealed spool can clog the extruder, and parts warp off the bed if you look at them wrong.

The moisture reality. This is the best-documented number in the category: CNC Kitchen's conditioning showed PA6 samples reaching ~3% moisture versus ~0.7% for PA12, and PA6-CF dropping to 56% of its dry tensile strength after moisture conditioning. That's why the community preference is settled — pick PA12-based grades (Bambu PAHT-CF, NylonX) over PA6. Bambu's own wet-vs-dry data shows PAHT-CF declining 12–18% versus 40–45% for normal PA-CF. Most owners miss the kicker: the part reabsorbs moisture in service and changes properties — design for the conditioned state, not the as-printed state.

The warping ladder (from Sept 2026 owner threads in the Engineering Filament Lab, where small ~3 cm parts were warping even with chamber heaters):

1. Dry to ≤15% RH before printing — always, even new spools.
2. Glue stick on smooth PEI; Bambu's PA-CF profile with bed dropped to 65 °C worked for one owner where 100 °C beds failed.
3. Wide brim, elephant-foot compensation to 0, fans off.
4. Chamber heat: 35–40 °C is enough per one practitioner; preheat the bed 30–40 min.
5. Still failing: Vision Miner Nanopolymer adhesive eliminated warping on unfilled nylon even without a brim for one owner; another reports a KDEAVI plate running PA12/PA6 glue-free for hundreds of hours.
6. Accept the verdict from the threads: no truly glue-free engineering plate exists. Adhesive is cheap insurance against a failed print on $95/kg filament. And geometry dominates — higher infill makes bed-holding nearly impossible.

Overdrying is real too: one owner dried PA612-CF15 for 10 days at 100–104 °C and got poor top surfaces — 10 days at 100 °C is excessive. Also worth knowing: PA612-CF15 drew a batch-variance warning from one owner (30+ kg printed fine, then a bad batch), single-source — and Polymaker renamed PolyMide PA6-CF to Fiberon PA6-CF20 (same formula), so old PolyMide-branded stock still circulates. Bambu is explicit that PAHT-CF is "unsuitable for use with open-frame printers."

The price ladder per kg (Sept 2026): Polymaker Fiberon PA6-CF20 $40–53 < Xtellar 645 $60 < Bambu PAHT-CF $94.99 < NylonX ~$121–126 < Prusament PA11 ~$125–153. PAHT-CF is the default buy — cheapest entry to CF-nylon, PA12-based, AMS-compatible. Prusa's PA11 is the premium impact/chemical-resistance pick but needs their PA sheet or equivalent for adhesion, since nylon won't stick to bare PEI.

Every filled grade needs a hardened steel nozzle (chopped fiber destroys brass within a few hundred grams) — 0.6 mm recommended for CF grades — and plain nylons are fine on brass. Prusa recommends active filtration for PA11-CF (odour + ultrafines), which is your ventilation cue for the bedroom article.

Rung 6: the exotics — PC, PP, POM, and who they're actually for

Carbon-fiber composite filament, one of the exotics.

Polycarbonate is the "last resort when PETG/ABS won't survive heat or impact" filament. Pure PC wants 270–310 °C nozzles, a 100–135 °C bed, and a fully heated enclosure; it warps aggressively and bonds to plates so hard you need a release layer or it damages the sheet. The pragmatic buy is Prusament PC Blend ($49.99/kg, glue stick ships free) — engineered to print easier, genuinely simpler than pure PC, though large models still warp. Pure Polymaker PolyMax PC runs ~$53/kg. PC emits noticeable odor at print temps — ventilate.

POM/acetal (Delrin) is the gear-and-bearing specialist: the lowest friction and best wear resistance you can print, the highest stiffness — "the strongest, toughest, best layer adhesion material you can print with" once dialed in, per a Bambu forum practitioner who prints POM parts to 150 mm on a G10/Garolite bed at 110 °C. The price: bed adhesion is legendarily bad, and POM can release formaldehyde when overheated — emission data is UNVERIFIED in this research, so ventilate regardless. Gizmo Dorks POM sits at ~$27/kg on a 224-day-stale crawl — re-verify live.

Polypropylene is the one-trick king: living hinges that survive thousands of flexes, excellent chemical resistance. The trick is the entire battle — PP barely sticks to anything, so it's packing-tape-on-the-bed, fan off, 3–4 perimeters minimum. Forward AM Ultrafuse PP (unfilled) is $94.55/kg; Caverna PP runs $220/kg. Fewer than a dozen active SKUs were tracked — expect stock gaps.

The ultra-polymers (PEEK/PEI/PEKK): don't buy them. Not yet. 3DXTech ThermaX PEEK runs $513–770/kg depending on spool size, needs 375–410 °C nozzles and an 80–140 °C actively heated chamber, and AON3D's guidance is brutal: PEEK printed below ~133 °C chamber temperature doesn't properly crystallize — the part looks like PEEK but doesn't deliver PEEK's properties. No sub-$2k consumer machine was verified PEEK-capable in this research. The filament is the cheapest part of that project.

Two oddballs worth naming: conductive PLA (carbon-black filled, 30 ohm-cm in X/Y but 115 ohm through layers) is a resistor that happens to be plastic — fine for touch sensors and LEDs, useless as wiring, and it heats under load. Don't confuse it with metal-look filaments, which are decorative and electrically insulating. And metal-sintering filament (BASF Ultrafuse 316L at $188/kg; Filamet at $360–422/kg): Virtual Foundry explicitly warns Filamet spools must not be dried — dryers damage the metal-loaded feedstock. The one filament where the instinct backfires.

The traps, short version

• Silk PLA as anything but decoration. Gorgeous, brittle, and one forum thread documents layer separation no settings fixed.
• PLA-CF sold as stronger PLA. A trade writeup is blunt: the fibers are an aesthetic/dimensional-stability product that can worsen PLA's brittleness. Expecting PA-CF performance from it is a category error.
• Glow-in-the-dark on brass. Budget the hardened steel before the spool.
• Bambu-priced engineering filament by default. PETG-CF at $30–38/kg vs budget grades that print fine dried; ASA at $46.99 vs Polymaker's ~$25. You're paying for RFID profiles and convenience, not mechanical advantage.
• "Recycled" with no paperwork. Filamentive publishes an ISO 14021 recycled-content declaration — credible. Unbranded "recycled" claims with no standard are the greenwashing tier; desktop-recycled filament is a hobby, not a supply chain.
• Above PETG, buy the workflow before the spool. A dryer fixes most "bad filament" threads; then an enclosure; then ventilation. Most "this filament is terrible" posts are wet spools, cold chambers, or missing PPE.

Bottom line

PLA+ for everything it can survive. PETG the day you need tougher, hotter, or outdoors — with a dryer. ASA for the enclosure-owning outdoor-parts crowd; ABS only while the price gap says so. TPU when it must bend, dried and slowed down. Nylon when PETG and ASA aren't strong or wear-resistant enough — PA12 over PA6, glue on everything, hardened nozzle, and no complaining about the workflow tax because you were warned. PC Blend for heat-stressed parts. POM for gears, PP for hinges, PEEK for... the year you buy a second mortgage on a printer. And the rule that makes every choice easy: buy the material your setup can run.

Sources & caveats

Drew on all 21 filaments/files/ profiles plus reviews/categories/filaments.md (the pre-digested category review, used as evidence scaffolding — articles written fresh, not stitched from review text): pla.md (Bambu PLA Basic $15.99 Sept 16 2026 drop, eSUN PLA+ ~$16–17 community pricing STALE, silk brittleness), petg.md (Bambu PETG HF $15.99, drying rule 65–75 °C/8–12 h, aggressive bed bonding, Overture ~$14 street STALE), tpu.md (hardness ladder, direct-drive rule, speed limits, price ladder eSUN ~$20 → NinjaFlex ~$108–118, Polymaker unit-error flag), abs.md (styrene/ethylbenzene VOCs, enclosure mandatory, owner headache/cough reports, Polymaker PolyLite ABS $19.99/kg, Voron ABS+ rejection), asa.md (PolyLite ASA $24.49–26.99 live Sept 20 2026, Bambu ASA $46.99, FB 31-comment thread ~$10/kg abandonment point, "ASA fog", Voron materials guide), nylon.md incl. all three deepening passes (CNC Kitchen PA6 3% vs PA12 0.7%, PA6-CF 56% dry-tensile-after-conditioning, FB warping threads Sept 2026 with glue/Vision Miner/Darkmoon findings, no-glue-free-plate verdict, overdrying and batch-variance signals, price ladder $40–153/kg, Prusament PA11), polycarbonate.md (PolyMax PC $53.32/kg, Prusament PC Blend $49.99, release-layer requirement, pure-PC demands), polypropylene.md (living-hinge reputation, $94.55–220/kg ladder, PP-tape adhesion, stock-gap note), pom-acetal.md (G10/Garolite practitioner recipe, formaldehyde caution, Gizmo Dorks $26.95 STALE), uht-polymers.md (3DXTech PEEK $513–770/kg, AON3D >120–133 °C chamber crystallization rule, no verified sub-$2k PEEK-capable machine, PEKK-A/PEI positioning), cf-composites.md (PETG-CF no-ventilation use case, Z-impact weakness, PLA-CF brittleness-worsening via trade writeup), specialty-filaments.md (silk/marble/glow/wood profiles, eSUN hardened-nozzle warning for glow), conductive-pla.md (30 ohm-cm X/Y / 115 ohm Z resistivity, heats-under-load), sintering-filaments.md (Filamet do-not-dry warning, BASF $188/kg / Filamet $360–422/kg), recycled-filaments.md (Filamentive ISO 14021). UNVERIFIED in this article: eSUN PLA+/Overture current street prices (180–340-day crawls); Bambu TPU-for-AMS pricing; X1C-style styrenics' long-term health data (none exists in this research); POM emission figures; Prusament ABS price; Gizmo Dorks POM live availability. No raw-quotes file exists in this corpus — all community experience is paraphrased, never verbatim quotes.