The
Filament
Bible.
PLA, PETG, ABS, ASA, TPU, Nylon — six materials, endless confusion. Here's the definitive guide to knowing exactly which spool to load for any job.
Why choosing the wrong filament is the #1 beginner mistake
Every week, r/3Dprinting and r/FixMyPrint are flooded with the same failed prints — warped corners, brittle parts, snapped prototypes. Nine times out of ten, the culprit isn't the printer settings. It's the material.
Here's the uncomfortable truth: the printer rarely matters as much as the material. A well-tuned Ender 3 with the right filament will outperform a $2,000 machine loaded with the wrong one. Understanding material science isn't just for engineers — it's the single biggest unlock for any maker looking to move beyond Instagram-worthy vases into prints that actually work in the real world.
In this guide, we break down the six core filament families — their strengths, weaknesses, ideal use cases, and the print settings that matter — with real data from community testing and material science research.
Reddit Insight: The most upvoted posts on r/3Dprinting consistently show a pattern — beginners fighting PETG stringing, ABS warping disasters, or Nylon moisture failures. All of these are avoidable with the right foundational knowledge before you hit print.
The Big Six — know your materials
An honest breakdown of each major filament type, with no marketing fluff. Difficulty ratings reflect real-world printability across a range of consumer FDM printers.
The crowd favorite and the rightful starting point for every newcomer. Made from renewable corn starch, PLA prints cold, smells faintly of maple, and forgives almost every mistake. Testing by Stefan at CNC Kitchen consistently shows PLA outperforming most other filaments in stiffness and rigidity — a counterintuitive result that surprises many.
Best for: Prototypes, figurines, decorative prints, educational models, learning your printer
PETG sits in the sweet spot between PLA's easy printability and ABS's durability — making it the all-purpose workhorse for functional parts. Excellent layer adhesion, minimal warping, and genuinely useful chemical resistance. The main gotchas: it strings like crazy if retraction is off, and it sticks almost too well to PEI beds. Print slowly and dial in retraction.
Best for: Mechanical parts, brackets, containers, snap-fit designs, translucent prints
The legacy workhorse — what LEGO bricks, car interiors, and electronics housings are made of. Excellent impact resistance, handles heat above 100 °C, and can be acetone-smoothed to a glass-like finish. The trade-offs are real though: warping without an enclosure, styrene fumes requiring ventilation, and a steeper learning curve. In 2026, most makers reach for ASA instead.
Best for: Automotive parts, electronics enclosures, acetone-smoothed display models
Think of ASA as ABS's weather-hardened successor. It was developed specifically to address ABS's UV weakness — where white ABS yellows and degrades outdoors in months, ASA holds its color and structural integrity for years. Similar print settings to ABS but with a matte finish that many prefer aesthetically. Still needs an enclosure, still has fumes — but the outdoor performance gain is dramatic.
Best for: Outdoor fixtures, garden prints, automotive trim, signage, anything UV-exposed
If it needs to bend, stretch, or absorb impact without breaking — TPU is your material. Rubber-like elasticity with real engineering durability. 95A Shore hardness (the most common) hits the sweet spot between printability and flexibility. The critical caveat: Bowden-tube printers fight TPU constantly. Direct-drive extruders are strongly recommended. Print slow, never rush.
Best for: Phone cases, gaskets, seals, wearables, drone bumpers, flexible hinges
The engineering-grade champion. Nylon prints parts with outstanding wear resistance, low friction coefficients, and a toughness that lets it flex under load without snapping. Gears, bushings, living hinges, functional brackets — this is where Nylon earns its reputation. The nemesis is moisture: Nylon absorbs water from the air aggressively and must be dried before printing and stored in sealed dry boxes. Skip this step and you'll print spaghetti.
Best for: Gears, bushings, living hinges, high-wear functional parts, industrial prototypes
Quick-pick decision guide
Answer these questions and you'll know which spool to grab. No engineering degree required.
| If your situation is... | The answer is... | Why |
|---|---|---|
| You just got your first printer | PLA | Lowest failure rate, no heated bed required, odorless, forgiving of temperature variation. |
| The part needs to survive outdoors, year-round | ASA | UV-stable, weather-resistant, won't yellow or become brittle under sunlight. PETG is acceptable for mild exposure. |
| You need flexibility — it must bend or compress | TPU | No other common filament offers genuine rubber-like elasticity. 95A hardness is the best starting point. |
| It's a mechanical part under load or stress | PETG | Strong layer adhesion, impact-resistant, easier to print than ABS/ASA. Upgrade to Nylon for gear or bushing applications. |
| The part will be in a hot environment (car dashboard, near electronics) | ABS or ASA | Both handle sustained temperatures above 100 °C. PETG deflects around 80 °C — a car in summer easily exceeds that. |
| It's a precision gear, bushing, or high-wear component | Nylon | Unmatched wear resistance and low friction coefficient. PA12 offers better dimensional stability than PA6. |
| It needs to look perfect — smooth surface, painted finish | PLA | Best surface finish out of the extruder. Easy to sand, prime, and paint. ABS offers acetone-smoothing as an alternative. |
| You need a fast, cheap batch of functional objects | PETG | Fast to print, widely available under $20/kg, durable enough for most household and workshop applications. |
| Translucent or clear aesthetic is required | PETG | PETG maintains optical clarity far better than other materials. Excellent for light diffusers, display covers, lenses. |
| You have a Bowden-tube printer and want flexibles | Upgrade first | TPU with Bowden = guaranteed headache. Upgrade to direct drive before attempting flexible filaments. |
Print settings reference card
Copy these baselines into your slicer. They won't be perfect for every printer — treat them as a tuned starting point, not gospel.
The moisture trap: PETG, Nylon, and TPU are all hygroscopic — they absorb moisture from the air and print with bubbling, popping, and surface blemishes when wet. If your print sounds like it's frying, your filament needs drying. Store all filament in sealed containers with desiccant. Invest in a dedicated filament dryer if you print Nylon regularly.
Community wisdom from r/3Dprinting
The hive mind has spoken. These are the distilled insights from thousands of posts, failed prints, and hard-won victories across the 3D printing subreddits.
The final verdict
If you're still unsure, these are the picks for the three most common situations every maker eventually faces.