How strong is PETG? Real numbers, honest limits.
"Strong" means different things — resisting a steady pull, surviving a drop, holding shape in a hot car. PETG scores differently on each, so here are the actual figures and what they mean for a part you'd order.
The short version: ~50 MPa tensile strength, rigid to ~75°C, and — the bit datasheets undersell — genuinely tough: it bends and bounces where other plastics crack. For brackets, mounts, clips, enclosures and outdoor parts, PETG is strong enough with margin to spare.
The numbers
| Property | PETG (typical printed) | What it means in practice |
|---|---|---|
| Tensile strength | ~45–53 MPa | A 10 mm² cross-section holds roughly 45–50 kg in a straight pull |
| Elongation at break | ~20–25% | Stretches and deforms before failing — you get a warning, not shrapnel |
| Impact toughness (Charpy) | ~8–10 kJ/m² | Survives drops and knocks that crack PLA outright |
| Heat deflection | ~70–80°C | Car cabins and warm electronics fine; ovens and kettles not |
| UV & water | Very good | Same polymer family as drinks bottles — outdoor parts last |
| Density | 1.27 g/cm³ | Light — a chunky bracket is still only tens of grams (and pence of material) |
Figures are typical for well-printed parts; exact values vary with filament brand and print settings — which is precisely the point of the next section.
Printing matters as much as the polymer
Two parts from the same filament can differ in strength by 2–3× depending on how they're printed. The levers that matter:
- Layer adhesion — FDM parts are weakest along layer lines. PETG's layers weld unusually well (better than ABS's), but only when temperature and cooling are dialled in properly.
- Orientation — a hook printed upright snaps at a layer line; printed flat, the load runs along the layers and it holds many times more. We choose orientation per part, based on how it will be loaded.
- Walls over infill — for strength, extra perimeter walls beat higher infill percentages gram for gram. Functional parts here get thick walls by default.
This is most of the answer to "why not just buy the cheapest print?" — the material is only half the strength; the setup is the other half.
PETG vs the alternatives
vs PLA: PLA is stiffer and slightly stronger in a straight pull but brittle — it snaps without warning and softens at ~55°C. PETG trades a little stiffness for far more toughness and heat headroom. Full comparison: PETG vs PLA.
vs ABS: similar tensile numbers on paper, but printed ABS parts often fail early along poorly-bonded layer lines, and ABS warps during printing. PETG prints more reliably and bonds better; ABS (and its UV-stable successor ASA) keeps the edge above ~80°C.
vs "just buy metal": for precision gears under heavy sustained load, high temperatures or safety-critical duty, metal remains the answer — and if your part is one of those, we'll tell you rather than print it.
So is PETG strong enough for your part?
For the parts people actually order — replacement parts, brackets, mounts, jigs, enclosures, adapters, outdoor fittings — yes, comfortably. It's why PETG is our stocked default (black, engineering-grade). If you're unsure, upload the model anyway: every file is reviewed by a human before printing, and "this needs to be thicker here" or "this isn't a job for plastic" costs you nothing to hear.
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