Frequently asked questions
The questions that come up most, answered from published manufacturer documentation. Each answer links to the page that covers it properly.
Questions
Which filament should I buy first?
A toughened PLA+ from a brand that publishes a diameter tolerance. It prints on any machine with no extra hardware and it is meaningfully less brittle than plain PLA at the same price. See best PLA filament.
What temperature should I print PLA at?
Prusa Research publish 185 to 235 C at the nozzle and 50 to 60 C at the bed for PLA as a class. The correct value inside that depends on your hotend, so run a temperature tower — see PLA print settings.
What is the difference between PLA and PLA+?
There is no standard behind the plus. In practice the grades sold under it are modified for impact toughness, so parts survive being dropped. It does not improve heat resistance. See PLA versus PLA+.
When should I switch from PLA to PETG?
When a part broke, when it gets warm, or when it lives outdoors. Prusa list impact resistance as PETG's noted property and low warping as PLA's. See PLA versus PETG.
Why does my PETG string so much?
Moisture first, temperature second, retraction third. Wet PETG strings in a way no retraction setting corrects, so drying comes before tuning. See PETG print settings.
Will PETG damage my build plate?
It can. PETG bonds chemically to smooth PEI and can tear material out of the sheet when the part is removed. Use a textured plate, or a glue stick as a deliberate release layer. See build plates.
How do I tell if my filament is wet?
Heat the hotend and extrude by hand for twenty seconds. Dry filament comes out as a smooth glossy strand, quietly; wet filament pops and the strand shows bubbles. See wet filament signs.
How long does dried filament stay dry?
Bambu Lab publish 2 to 7 days below 20 percent relative humidity, and 2 to 12 hours at around 55 percent, which is ordinary indoor air. See drying and storage.
What temperature do I dry filament at?
It depends on the material and the manufacturers disagree. Prusa publish 45 C for PLA and 55 C for PETG; Overture publish 50 C and 65 C. Both sets are on how to dry filament.
Does PLA need drying?
Usually not. PLA is the least hygroscopic common filament, so a fresh sealed spool prints fine. A spool left open for months in a humid room might. See does PLA need drying.
Can I dry filament in the oven?
We would recommend against it. Domestic ovens overshoot their setpoint and cycle widely, and PLA's published drying temperature is low enough that the overshoot can weld a spool into a solid block.
Do I need a hardened steel nozzle?
Only for filled filament: carbon fiber, glass fiber, metal-filled or glow-in-the-dark. E3D document substantial brass wear from abrasives within a few hundred grams. See nozzles.
How do I tell a worn nozzle from a clog?
A clog under-extrudes inconsistently and cleaning fixes it. Wear over-extrudes consistently and cleaning changes nothing. See the nozzle wear guide.
Does carbon fiber filament make parts heat resistant?
No. Heat deflection is a property of the base polymer, so carbon-filled PLA softens at the same temperature plain PLA does. Carbon adds stiffness and dimensional stability. See carbon fiber filament.
Which filament should I use for outdoor parts?
ASA. Prusa list UV and chemical resistance as its noted properties. PETG works for a season if you have no enclosure. PLA fails quickly from heat and UV. See outdoor filament.
Which filaments need an enclosure?
Prusa mark ABS, ASA, polycarbonate and polyamide as enclosure recommended. PLA, PETG and flexible materials are not. See does PETG need an enclosure.
Can I print TPU on my printer?
On a direct-drive extruder, yes. On a Bowden printer, Shore 95A is sometimes possible at very low speed and softer grades effectively are not, because soft filament buckles inside the tube. See TPU.
Are 3D printed parts food safe?
Not reliably. The channels between printed layers hold bacteria that washing does not remove, standard brass nozzles are not certified for food contact, and most filament has no published food-contact certification. See is PETG food safe.
Is resin printing worth it if I already print filament?
For miniatures and detailed models, yes. For functional parts, no — filament is better at almost all of them, and resin adds a chemical handling routine and a disposal obligation. See is resin printing worth it.
Is cheap filament worth it?
Usually, if it publishes a diameter tolerance and ships vacuum sealed. Those two checkable properties separate cheap filament from bad filament. See is cheap filament worth it.
Why do you not publish filament prices in your articles?
Because a price typed into an article is wrong within weeks. Prices here render from a live retail lookup and disappear entirely once they pass a freshness limit, at which point the button says “check price”. See how we choose.
Have you actually tested any of this?
No, and every page says so. We compile manufacturers' published specifications into comparable tables, cite each figure where it is used, and show the arithmetic. That is reproducible in a way a testing claim would not be. See how we choose.
Not answered here
The master material ledger puts every common filament on one table, and the site index lists every page. If your question is not covered anywhere, the contact form reaches us directly — and if the answer is a correction to something here, it goes to the top of the queue.