By A
CLEAR PETG
Glass-like PETG prints from settings you can copy into any slicer
EVERY GAP AND SEAM SCATTERS LIGHT
Gaps between lines
Any tiny air gap between extruded lines bends and scatters light, so the part looks frosted instead of clear.
Crossing lines
When lines cross at different angles layer to layer, each boundary becomes one more surface for light to bounce off.
Cooled seams
Plastic that cools before the next line lands doesn't fully fuse, and that seam shows up as cloudiness.
The goal
One solid, slowly laid, fully fused block with lines stacked in the same direction.
Fact source: RandoTechNerd Clear PETG guide
CALIBRATE FIRST, OR FLOW 1.0 WON'T WORK
E-steps
Dial in e-steps so extrusion matches what's commanded
PID tune
PID-tune the hotend for a steady temperature
Level bed
Level the bed so the first layer goes down evenly
Dry filament
Dry the filament before you print
Pick filament
Elegoo PETG: the clearest in my testing. Overture was less clear for me, though one maker got clearer complex parts with it (maybe more heat, or an odd batch).
Fact source: RandoTechNerd Clear PETG guide
HOT, SLOW, THIN LAYERS, NO FAN
Fact source: RandoTechNerd testing on an Ender-5 Pro in Orca Slicer
THE INFILL IS THE PART
99.999% sparse infill
Not 100%. At 99.999% the slicer keeps it as aligned infill instead of switching to solid-infill patterns.
Aligned rectilinear, 90°
Aligned rectilinear pattern with infill direction 90°, so every layer's lines stack the same way.
1 wall
Just one wall loop, so most of the part is clean, aligned infill rather than a stack of perimeters.
0 top, 0 bottom shells
No top or bottom shell layers, so no solid-pattern layers end up crossing the aligned lines.
Fact source: RandoTechNerd Clear PETG guide
SLOW AND WIDE LINES FUSE BEST
Walls 120% of nozzle (0.72 mm); infill and top 110% (0.66 mm) Acceleration 500 mm/s², max volumetric speed 10 mm³/s From testing, 20 to 40 mm/s is the sweet spot
Fact source: RandoTechNerd testing, Clear PETG guide
KEEP THE NOZZLE OFF FINISHED INFILL
Every slicer
Retraction 0.3 mm at 60 mm/s Z-hop 0.5 mm Seam at back
Cura
Set Combing Mode to "Not in Skin" Keeps travel off the finished surface
Orca
No Combing equivalent Use z-hop and Avoid crossing walls Otherwise travel drags lines across the part
Fact source: RandoTechNerd Clear PETG guide
COPY THE RECIPE INTO YOUR SLICER
Fact source: RandoTechNerd Clear PETG guide
DOWNLOAD THE FREE TEST TILE
Free on Printables: printables.com/model/1322174 Orca .3mf with every setting built in (0.6 mm nozzle) A 0.4 mm version is coming Includes 20 x 20 x 4 mm tile STL and Clear Ironing test .3mf
Ironing test: 15% flow, 15 mm/s, 0.1 mm spacing, zig-zag. Clarity drops past 1 to 2 mm of thickness.
PRINT IT, PICK THE CLEAREST, KEEP IT
A multi-tile .3mf, one setting per tile Print it once, pick the clearest tile Keep that tile's settings for your clear parts Still testing: infill/wall overlap and per-tile settings in Orca
Still testing: infill/wall overlap (25%) and getting Orca to vary settings per tile
PRINT A TILE AND SHOW ME YOUR RESULTS
Watch the video and read the full guide at randotechnerd.com/tutorials · Questions: discord.gg/randotechnerd
Thank you Polymaker for providing clear PETG and PCTG, and EIBOS for providing the Cyclopes filament dryer, both at no cost. Filament links on the guide include Amazon affiliate links (3%, funds more PCTG testing).