Troubleshooting
How do I fix blobs and zits?
First in this ranking: Polymaker Polylite PLA.
- Nozzle190–230 °C (374–446 °F)
- Bed25–60 °C (77–140 °F)
- Speed40–60 mm/s
- Dry55 °C (131 °F) for 6 h
- Density1.17 g/cm³
Ranked filaments
| Rank | Filament | Material | Nozzle | Bed | Price / kg | Datasheet | Buy |
|---|---|---|---|---|---|---|---|
| 1 | Polymaker Polylite PLAPolyLite PLA stores a nozzle of 190–230 °C (374–446 °F) and drying at 55 °C (131 °F) for 6 h. Pressure advance is not a field. Dry at the listed temperature, then calibrate advance for this spool. | PLA | 190–230 °C (374–446 °F) | 25–60 °C (77–140 °F) | — | Datasheet | |
| 2 | Prusament PLAPrusament PLA stores 205–225 °C (401–437 °F) and a bed of 40–60 °C (104–140 °F). A pressure-advance value from another PLA does not transfer. The row has no advance number to copy. | PLA | 205–225 °C (401–437 °F) | 40–60 °C (104–140 °F) | — | — | |
| 3 | Bambu Lab PLA BasicPLA Basic’s sheet lists 190–230 °C (374–446 °F) and retraction of 0.6–1.0 mm. That retraction is a starting band, not a zit cure by itself. The sheet does not list pressure advance. | PLA | 190–230 °C (374–446 °F) | 35–45 °C (95–113 °F) | — | Datasheet | |
| 4 | Polymaker Polylite PETGPolyLite PETG stores 220–250 °C (428–482 °F) and a bed of 70–90 °C (158–194 °F). The same three tunes apply. PETG is not given a separate zit distance in this consensus. | PETG | 220–250 °C (428–482 °F) | 70–90 °C (158–194 °F) | — | Datasheet |
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A zit at the start or end of a loop is unused pressure at the seam. Sanding it off works once. The consensus tunes the pressure instead.
Order of work
Dry the spool. PolyLite PLA lists 55 °C (131 °F) for 6 h. Other rows may not list hours. The bands by material are on drying.
Then retraction, inside the extruder’s band. Direct drive is about 0.5–1 mm on the ooze page. PLA Basic’s sheet lists 0.6–1.0 mm. A longer retraction can trade a zit for a clog.
Then pressure advance, also called linear advance. How to calibrate flow and pressure advance is the sequence, including the temperature tower. This page does not have a K value to type in.
Then seam placement. Park an aligned seam on a rear corner you can sand. Random seam is a scatter, not a cure.
What the ranked rows are for
Prusament PLA, PLA Basic, and PolyLite PETG are examples of spools you calibrate one at a time. None of them store pressure advance. A profile that looked clean on one of them can zit on the next because the advance value moved with the spool.
Pros and cons
Pros
- The fix list is short: pressure advance, retraction, seam, dry filament.
- No fake K factor is printed. The consensus did not supply one.
Cons
- A random seam hides the defect on a round part and makes a painted part harder to sand in one line.
- Drying hours are missing on Prusament PLA and PolyLite PETG. Only PolyLite PLA stores 6 h among these four.
Printer considerations
- Pressure advance and linear advance are the same idea under two names. The consensus names both. It does not publish a K value.
- Seam placement is a slicer choice: aligned, rear, or random. Random spreads the zit. It does not remove the pressure that caused it.
- Direct-drive retraction stays near 0.5–1 mm. Lengthening it to mash a zit flat is how the clog page’s long retraction starts.
What the community says
The consensus is that zits and blobs come from seams and pressure. Tune pressure advance, retraction, and seam placement, and dry the filament.
- Community source, r/BambuLab 1kpfdwo
- Community source, r/FixMyPrint 1mbigcb
- Community source, r/3Dprinting va8t4p
- Community source, r/3Dprinting 10lyhx4
- Community source, r/FixMyPrint zz67i6
Sources & notes
Accessed 15 October 2026.
- Bambu PLA Basic technical data sheet V3.0 datasheet
- PolyLite PLA technical data sheet datasheet
- PolyLite PETG technical data sheet datasheet
- Community source, r/BambuLab 1kpfdwo reddit
- Community source, r/FixMyPrint 1mbigcb reddit
- Community source, r/3Dprinting va8t4p reddit
- Community source, r/3Dprinting 10lyhx4 reddit
- Community source, r/FixMyPrint zz67i6 reddit
Related questions
- How do I get good PLA prints?PLA
- Do I need to dry filament, and how?Drying
- How do I calibrate flow rate and pressure advance for a new filament?Troubleshooting
- How do I stop oozing between moves?Troubleshooting
Questions
What pressure advance should I enter?
None from this page. Calibrate it for the spool. The flow page is the order: temperature, flow, then pressure or linear advance. OrcaSlicer is the tool that consensus names for the calibration, on the flow page.
Will a lower temperature remove a seam zit?
Temperature is the ooze lever, and a wet spool makes both ooze and blobs. Dry first. Then set seam and pressure advance. Dropping under the nozzle minimum is a clog, not a surface fix.