PETG-CF Print Settings: Temps, Drying, and Tuning That Actually Work

You bought PETG-CF for the stiffness without the nylon price tag. Then your first print came out stringy, dull, and weak between the layers. Before you blame the spool, check your settings. PETG-CF looks like carbon nylon, but it prints by its own rules — and most presets are written for plain PETG, which gets you maybe halfway there. Here's what actually works on a real machine.

Dry the spool first, no exceptions

PETG absorbs moisture. Carbon fiber doesn't stop it — it just makes the failure less obvious. Wet PETG-CF prints matte, strings across every gap, and layers peel apart under load. Dry it at 60-65°C for four to six hours before you start, and keep it in a dry box while printing. This one step fixes more PETG-CF problems than every other setting combined.

Temps, speed, and fan that actually work

Run the hotend at 250-260°C. Start at 255 and tune from there — too cold and the layers don't fuse, too hot and it oozes. Set the bed to 70-80°C for the first layer, then hold 70°C for the whole print. Print at 40-60 mm/s; carbon fiber doesn't want to be rushed. Keep the part fan off for the first two or three layers, then run 30-50%. That's the difference between curling corners and flat parts.

Retraction and nozzle choice

On a direct-drive machine, start at 0.8-1.5 mm retraction at 30-40 mm/s. Bowden setups need more — expect 3-5 mm. And do not run this filament through a brass nozzle. The carbon fiber grinds brass out fast; use hardened steel. A 0.6 mm nozzle is the sweet spot for CF filament — fewer clogs, stronger parts, and you won't miss the detail on functional parts anyway.

First layer and bed prep

Slow the first layer to 25-30 mm/s and run it a touch thicker at 0.24-0.28 mm. Textured PEI grabs PETG-CF well. If it still won't stick, wash the sheet with warm water and dish soap — not just IPA — and let it dry fully. Most adhesion complaints with PETG-CF are actually dirty build plates.

What we run

We test filament on the same machines you're printing on. The spool we keep coming back to for PETG-CF is Elegoo's 1 kg — it's consistent, dries well, and the settings above are exactly what we run with it. Grab it here: Elegoo PETG-CF with tested print settings.

Affiliate disclosure: some links are affiliate links — you pay the same price, we earn a small commission that keeps our testing free.