How to print PETG: temperatures, cooling and stringing

Nozzle and bed temperatures for PETG, how much cooling to use, which build plate to pick, and how to stop the strings.

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Updated 2026-10-16

Short answer

Print PETG at about 230–250 °C on a bed of 70–90 °C, inside the ranges Prusa and Polymaker give, with the part cooling fan low or off for the first layers. Use a textured plate, or glue stick as a release layer on smooth PEI, because PETG can stick hard enough to damage it.

Most stringing goes away with dry filament, a slightly lower nozzle temperature and a little more retraction.

When PETG is the right choice

PETG is PET, the plastic of drink bottles, with glycol added. The glycol makes it less brittle and easier to print. Prusa's material guide sums it up as easy to print, tough, with good layer adhesion and little warping.

Compared with PLA, PETG bends before it breaks and handles more heat. Polymaker's PolyLite PETG data sheet gives a glass transition of 81 °C and a heat deflection temperature of 78 °C at 0.45 MPa. Prusa states PETG parts suit most indoor and outdoor uses below 80 °C. It also resists water and humidity.

That makes PETG a good choice for clips, hooks and brackets that flex, for parts that get wet, and for parts that sit outside. It is less suited to fine detail: bridges, steep overhangs and small text come out cleaner in PLA, and supports are harder to remove. For parts in strong sun all year or near real heat, ASA is the usual next step. Our guide to choosing a filament compares the materials.

If you want to try it, 3DJake has a range of PETG filamentPartner link from several makers. The settings below are starting points. Check the maker's own temperature range on the spool.

PETG in the Printaro generators

Many outdoor and garden generators here name PETG in their print tips. Of the 18 tools in the outdoor category, 16 mention it, and of the 16 garden tools, 13 do. The tips usually say "PETG or ASA" for parts that live outside, such as the tent stake, and PETG for parts that hold water, such as the self-watering pot. Car parts like the headrest hook say PETG, ABS or ASA, because a car in the sun gets hot enough to bend PLA.

These are tips, not settings: the files you download are the same whatever you print them in. The generators don't set a material for you.

Temperatures and cooling

Filament makers give a range, and the right value inside it depends on your printer and the spool. Two examples from the makers' own pages:

Prusa's material guide: 230 °C for the first layer and 240 °C after that.
Polymaker PolyLite PETG: 230–260 °C, with the cooling fan between off and 20 %, at 50–100 mm/s with a 0.4 mm nozzle.

Finding your temperature

The fastest way to find your temperature is a temperature tower. Set the highest temperature to 250 °C, the lowest to 220 °C and the step to 5 °C. In the slicer, change the temperature at the start of each block, as the tool page explains. Pick the block with the cleanest overhang, a straight bridge and the fewest strings.

Hotter PETG bonds its layers better and is stronger. Cooler PETG strings less and shows finer detail. For a clip or a bracket, lean to the hot end. For a part that has to look clean, lean to the cool end.

Cooling works the other way from PLA. PLA likes a strong fan. PETG needs less: Prusa suggests the fan off for the first few layers and at about half power after that, or off completely for the toughest parts. More fan gives sharper overhangs but weaker layer bonds. If a part splits along a layer line, turn the fan down.

Bed and first layer

PETG needs a heated bed. Polymaker gives 70–80 °C, and Prusa's guide uses 85 °C for the first layer and 90 °C after that. Start around 80 °C and adjust if the first layer doesn't stick.

The bigger issue is that PETG often sticks too well. On a smooth PEI sheet it can bond so strongly that it tears pieces out of the surface when you remove the part. Prusa advises a textured or satin sheet for PETG, and glue stick as a separating layer if you print on smooth PEI. Polymaker lists polycarbonate and textured PEI plates, with glue when needed.

Let the plate cool before you take the part off. Most PETG prints let go on their own once the bed is cold. Our guide to a first layer that sticks covers cleaning, leveling and brims.

PETG also doesn't like being squashed. A first layer that is too low drags plastic along with the nozzle and builds up blobs. If the first layer looks rough or wavy, raise the nozzle a little.

Stringing

Strings are thin hairs of plastic between parts of the print. They come from plastic oozing out of the nozzle while it travels. PETG strings more than PLA because it stays runny longer. Work through the causes in this order:

Dry the filament. PETG takes up water from the air, and wet filament strings and pops. Polymaker gives 65 °C for 6 hours for drying.
Lower the nozzle temperature by 5–10 °C, as long as layers still bond well.
Raise retraction a little. Prusa names higher retraction and a lower temperature as the two settings that cut stringing. Change one setting at a time.
Print a retraction test after each change. Strings between the towers show at once whether it helped.
Leave a few fine hairs. A short blast with a heat gun shrinks them away, and they are easy to pull off.

Common mistakes

Printing on bare smooth PEI. The part can tear the coating. Use a textured plate or glue stick.
Using PLA cooling. A full fan from the first layer weakens PETG and can lift corners.
Squashing the first layer. PETG needs a slightly higher first layer than PLA.
Wet filament. A spool that has been open for weeks can string no matter what you change in the slicer. Dry it first.
Taking the part off a hot bed. It sticks hardest while hot. Wait until the plate is cool.
Expecting PLA detail. Small text, sharp overhangs and bridges look rougher in PETG. Use PLA where looks matter more than toughness.

Frequently asked questions

What temperature should I print PETG at?

Prusa and Polymaker give 230–260 °C between them for the nozzle and 70–90 °C for the bed. Print a temperature tower to find the best value for your spool.

Should the fan be on for PETG?

Low or off. Prusa suggests off for the first few layers, then about half power. Off completely gives the strongest layers.

Why is my PETG stringing so much?

Usually wet filament, too high a temperature or too little retraction. Dry the spool, lower the temperature by 5–10 °C and test with a retraction test.

Can PETG go outside?

Yes. It resists water. Prusa rates PETG parts for use below about 80 °C, and Polymaker gives a heat deflection temperature of 78 °C. For parts in strong sun all year, ASA is the usual alternative.

Does PETG need an enclosure?

No. PETG warps little and prints on an open printer. An enclosure is for ABS and ASA.