PETG has a reputation for being fussy. In our experience, ninety percent of the “PETG is fussy” complaints we hear from Kiwi makers are not really PETG’s fault — they’re print settings tuned for someone else’s climate, on someone else’s printer, with filament that has been sitting open in an Auckland garage for a fortnight.
This article is the settings sheet we wish we’d had when we started printing PETG in New Zealand. Every number below has been validated on the R3D PETG Pro range we sell, on the printers that walk through our workshop every week (Bambu, Prusa, Creality, Voron, Kingroon, and a few Voxelabs). Where settings differ between printers, we say so.
If you only read one section, read the moisture troubleshooting section near the bottom — that’s where most NZ-specific problems hide.
Where to start: our baseline PETG profile
Use these numbers as a starting point. They produce clean, strong prints on every well-tuned FDM printer we’ve tested with R3D PETG Pro. Tune from here.
| Setting | Starting value | Notes |
|---|---|---|
| Nozzle temperature | 235°C | First layer 240°C, drop to 230°C if stringing |
| Bed temperature | 75°C | First layer 80°C, then drop to 70°C |
| Print speed | 50 mm/s | Outer wall 30 mm/s, infill up to 80 mm/s |
| Initial layer speed | 20 mm/s | Lower if you see corner curl |
| Cooling fan | 40% | 0% on layer 1, ramp from layer 3 |
| Retraction (Bowden) | 4-6 mm @ 35 mm/s | Cap below 6 mm to avoid hot-end jams |
| Retraction (direct) | 0.8-1.5 mm @ 40 mm/s | Direct-drive needs much less than Bowden |
| Z-hop | Off | Only enable if your stringing is severe |
| Line width | 0.42 mm | For a 0.4 mm nozzle |
| Wall count | 3 | PETG layer adhesion is excellent — fewer walls than PLA is fine |
| Top/bottom layers | 5 | PETG slumps slightly more than PLA |
| Infill | 20% gyroid | Gyroid prints faster and stronger than grid in PETG |
| Build plate | Textured PEI | Smooth PEI works but needs a thin glue layer |
If you’re printing R3D PETG Pro CF Black, nudge the nozzle temperature up by 5-10°C (245-250°C) and use a hardened nozzle. Carbon fibre is mildly abrasive — a standard brass nozzle will round out within a kilo or two.
First-layer tuning is half the battle
PETG sticks to PEI build plates too well. A 75°C bed and a slightly raised nozzle is the safest combination for the first layer; pressing PETG hard into hot PEI can leave divots in the build plate when you peel the part off.
A few first-layer rules that have saved us hours:
- Add a 0.05 mm Z-offset above your normal PLA setting. PETG flows wider, not squashier.
- Skip the glue stick on a textured PEI plate. It’s not needed and makes the prints lift cleanly without fighting them.
- Use a thin layer of PVA glue (or hairspray) on a smooth PEI plate to act as a release agent — this protects the plate when prints adhere too well.
- Wash the plate weekly with warm water and a drop of dish soap. PETG adhesion drops sharply on oily plates and rises sharply once cleaned.
If your first layer is “elephant footing” (squashing outwards), drop the bed temperature five degrees rather than tightening the Z-offset further.
Cooling: less than you think
The standard PLA reflex is “more fan equals better surface finish”. With PETG, that destroys layer adhesion.
Our rule of thumb:
- Functional parts (brackets, jigs, anything load-bearing): 0-25% fan.
- Visual parts (overhangs, fine detail, miniatures): 40-60% fan.
- Bridges: 100% for the duration of the bridge, then back to your default.
If you see weak inter-layer bonding (parts that snap cleanly along a layer line with light pressure), you have either too much fan, too low a nozzle temperature, or both.
Speed and the outer wall trick
You can run R3D PETG Pro at high infill speeds — 80 mm/s and above is fine — but the outer wall is where surface quality lives or dies. Slow the outer wall to 25-35 mm/s independent of your other speeds. This single change is the difference between “smooth and uniform” and “visible seam plus shiny patches”.
Travel speed: leave it high (150-200 mm/s) so the nozzle doesn’t dwell over soft areas. PETG benefits from short, fast travel moves more than it suffers from them.
Retraction without stringing
PETG strings more than PLA. That’s physics, not your printer.
On a direct-drive machine, start at 0.8 mm at 40 mm/s and only increase if stringing persists. Going above 2 mm on direct-drive almost always causes more grinding than stringing.
On a Bowden machine, start at 4 mm at 35 mm/s. Go up to 6 mm if needed, but stop there — past 6 mm you risk pulling melted filament back into the heatbreak and jamming.
If you’ve tuned retraction to the maximum and still see hair-like strings, the cause is almost certainly moisture in the filament — see below.
The moisture story: where NZ prints go wrong
Auckland’s relative humidity sits between 78% and 89% year-round. Wellington, Hamilton, Tauranga, and Christchurch are not much better. PETG absorbs moisture continuously once the original bag is open, and the symptoms creep in long before you’d think.
We covered the storage side of the workflow in our Auckland filament storage guide. Here are the print-time symptoms to watch for, ranked by severity:
Early signs (filament has been open 2-4 days)
- Faint hissing at the nozzle, like a hot pan with a drop of water.
- Light stringing that wasn’t there a few prints ago, even though retraction is unchanged.
- Surface bubbles when printing translucent — most visible on R3D PETG Pro Translucent.
- Slightly fuzzier outer walls under raking light.
At this stage, six to eight hours in a Kingroon 3D-X2 active dryer at 65°C brings the spool back to like-new.
Moderate moisture (1-2 weeks open in NZ humidity)
- Loud popping and crackling at the nozzle.
- Stringing that retraction can’t fix — adding more retraction now makes prints worse because the filament jams in the heatbreak.
- Layer adhesion drops noticeably. Test parts snap on the layer line with very little force.
- Inconsistent extrusion width — visible “ribbing” along walls.
Dry the spool for at least eight hours at 65°C. If the printer is in a humid space, run the next print directly from the dryer. The Kingroon 3D-X2 is designed exactly for this — you can leave it heated while feeding filament out of the lid.
Severe (filament forgotten for a month)
- Prints fail. Stringing turns into webs, extrusion stutters, and parts delaminate.
- Visible bubbles or steam coming off the nozzle in the print’s first minute.
- The spool weighs noticeably more than the date you opened it. PETG can absorb 1-2% of its mass in water.
Dry for twelve hours at 65°C, weigh before and after, repeat if the spool loses more than 5 g during a single drying cycle. We’ve recovered spools that gained 35 g of water this way.
Printer-specific tips we’ve seen
- Bambu A1 and P1 series: Reduce default outer-wall acceleration; the factory defaults are fast enough to cause PETG seam blobs. Bambu Studio’s “PETG HF” preset is a good starting point, but drop wall acceleration to 2000 mm/s².
- Prusa MK4 / MK3S+: PrusaSlicer’s stock PETG profile is conservative and reliable. Lower retraction to 1.5 mm if you’re on the MK4 direct drive.
- Creality Ender 3 / S1 Pro: Make sure your part cooling duct points cleanly at the nozzle tip. Stock ducts blow PETG too hard and cause delamination — the Hero Me or 5015 mods help a lot.
- Kingroon KP3S / KLP1: These run hotter at the nozzle than the thermistor reports. Start ten degrees cooler than our baseline.
- Voron / Vorondesign machines: PETG is happiest on a Voron at lower speeds than ABS — drop the print speed by 30% from your ABS profile.
A clean PETG checklist before every print
Print this and tape it to the workshop wall.
- Did the spool come straight from sealed storage or the dryer? If neither, dry it.
- Is the build plate clean? Wash it if it’s been more than a week.
- Is the part-cooling fan set sensibly for the part type?
- Have you slowed the outer wall to ~30 mm/s?
- Is the bed temperature high enough for the first layer to “wet out” properly?
- For translucent prints, is the spool dry dry? Translucent PETG shows moisture defects ten times faster than opaque.
Tick all six and your prints will be boringly consistent — which is exactly what you want.
What this gets you
Once your PETG profile is dialled in for NZ conditions, you stop fighting the material and start using it the way it was designed to be used: functional parts that survive Kiwi summers, tools and jigs that don’t crack under load, and prints that look good enough to give away or sell.
We use these exact settings on the R3D PETG Pro Gray spools sitting next to our Kingroon dryer right now. If you’re starting from scratch, the lowest-fuss kit is one spool of Gray or Black plus a Kingroon 3D-X2 dryer. That combination solves both the print-quality and the storage problem in one buy.
If your prints still look off after working through the checklist, get in touch — we’ve yet to meet an FDM printer in NZ that R3D PETG Pro can’t print well on, and we’d rather help diagnose than have you blame the filament.