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PETG GF — Glass Fiber Reinforced PETG

PETG GF (glass fiber reinforced PETG) is one of the most popular materials for large structural and outdoor prints on the G1. The glass fibers dramatically reduce warping and improve dimensional stability compared to plain PETG.

Why use PETG GF

Section titled “Why use PETG GF”
  • Reduces warping significantly — especially important on large flat geometry
  • Better dimensional stability — parts hold their shape over time and with temperature changes
  • Outdoor performance — UV resistance and structural rigidity
  • Lower cost than engineering materials (PA, PC) while offering meaningful reinforcement
  • Same print temperatures as standard PETG — easy to switch

Glass fiber percentage — which to choose

Section titled “Glass fiber percentage — which to choose”
Fill %When to use
10% GFGood compromise: better rigidity than plain PETG, still smooth surface finish
20% GFMaximum stability and warp resistance; surface is rougher, fibrous texture visible

For products where surface finish matters (visible faces, design objects), start with 10% GF. For structural, technical, or outdoor parts where appearance is secondary, 20% GF.

Suppliers tested

Section titled “Suppliers tested”
SupplierNotes
FormfuturaRecommended starting point. Available in clear, 10% GF, 20% GF. Competitive price. Formfutura sources from consistent compound suppliers. Contact Formfutura sales for B2B pricing.
PolymakerSimilar quality to Formfutura, slightly more premium positioning. Chinese manufacturer.
NanoviaMore premium price point. Not personally tested by Ginger team as of 2026.

Coloring PETG GF

Section titled “Coloring PETG GF”

Standard PETG GF pellets come with a white pigment. To produce colored prints:

  • Use Liquid Masterbatch — add in a % to reach the target color (check masterbatch compatibility with PETG)
  • Solid masterbatch pellets: minimum 2% concentration for homogeneous output; changes viscosity slightly
  • For clear/natural base: request “GF clear” or “GF natural” from the supplier — then add color with liquid masterbatch
Section titled “Print settings”
ParameterRecommended value
Feeding zone220–230°C
Melting zone235–245°C
Nozzle zone240–250°C
Bed temperature70–80°C
Cooling20–40%; ramp up gradually
Line widthSame as standard PETG profile

Start from the standard PETG profile in Ginger Slicer and tune from there.

Formfutura PETG GF — confirmed settings

Section titled “Formfutura PETG GF — confirmed settings”
ZoneTemperature
Feeding Zone220°C
Melting Zone240°C
Nozzle Zone240°C

These values are confirmed for Formfutura PETG GF grades (10% and 20%). Other suppliers may require fine-tuning within the 220–250°C range.

Overhang behavior

Section titled “Overhang behavior”

PETG GF is more challenging on overhangs than plain PETG or PLA:

  • The stiff fibers make the material less flexible, so overhangs sag or separate more easily
  • Fix: reduce print speed on overhang sections, increase cooling
  • Test: print only the first third of the piece on overhangs before committing to a full print

Extruder wear

Section titled “Extruder wear”

The G1 extruder is built for abrasive materials. The barrel, screw, and nozzle are made from hardened stainless steel specifically to handle glass fiber, carbon fiber, and similar reinforced pellets. No special nozzle is required.

Section titled “Related notes”