{
  "question": "How do I fix blobs and zits?",
  "slug": "blobs",
  "useCase": "troubleshooting",
  "useCaseLabel": "Troubleshooting",
  "updated": "2026-10-15",
  "shortAnswer": "Blobs and zits come from seam pressure. Tune pressure advance, retraction, and where the seam sits, and dry the filament before you blame the spool.",
  "recommendedMaterials": [
    "pla",
    "petg"
  ],
  "printerConsiderations": [
    "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."
  ],
  "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."
  ],
  "community": "The consensus is that zits and blobs come from seams and pressure. Tune pressure advance, retraction, and seam placement, and dry the filament.",
  "related": [
    "ooze",
    "flow",
    "drying",
    "pla_print"
  ],
  "faq": [
    {
      "q": "What pressure advance should I enter?",
      "a": "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."
    },
    {
      "q": "Will a lower temperature remove a seam zit?",
      "a": "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."
    }
  ],
  "sources": [
    {
      "title": "Bambu PLA Basic technical data sheet V3.0",
      "url": "https://cdn.shopify.com/s/files/1/0584/7236/6216/files/Bambu_PLA_Basic_Technical_Data_Sheet_bf3411ce-be39-4db7-9669-1b4671d2196b.pdf?v=1734060943",
      "kind": "datasheet"
    },
    {
      "title": "PolyLite PLA technical data sheet",
      "url": "https://cdn.shopify.com/s/files/1/0548/7299/7945/files/PolyLite_PLA_TDS_EN_V5.4.pdf",
      "kind": "datasheet"
    },
    {
      "title": "PolyLite PETG technical data sheet",
      "url": "https://cdn.shopify.com/s/files/1/0548/7299/7945/files/PolyLite_PETG_TDS_EN_V5.4.pdf",
      "kind": "datasheet"
    },
    {
      "title": "Community source, r/BambuLab 1kpfdwo",
      "url": "https://www.reddit.com/r/BambuLab/comments/1kpfdwo/",
      "kind": "reddit"
    },
    {
      "title": "Community source, r/FixMyPrint 1mbigcb",
      "url": "https://www.reddit.com/r/FixMyPrint/comments/1mbigcb/",
      "kind": "reddit"
    },
    {
      "title": "Community source, r/3Dprinting va8t4p",
      "url": "https://www.reddit.com/r/3Dprinting/comments/va8t4p/",
      "kind": "reddit"
    },
    {
      "title": "Community source, r/3Dprinting 10lyhx4",
      "url": "https://www.reddit.com/r/3Dprinting/comments/10lyhx4/",
      "kind": "reddit"
    },
    {
      "title": "Community source, r/FixMyPrint zz67i6",
      "url": "https://www.reddit.com/r/FixMyPrint/comments/zz67i6/",
      "kind": "reddit"
    }
  ],
  "recommendations": [
    {
      "rank": 1,
      "note": "PolyLite 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.",
      "brand": "Polymaker",
      "product": "Polylite PLA",
      "material": "PLA",
      "url": "/brand/polymaker/polylite-pla",
      "nozzle": "190–230 °C (374–446 °F)",
      "bed": "25–60 °C (77–140 °F)",
      "pricePerKg": null,
      "datasheetUrl": "https://cdn.shopify.com/s/files/1/0548/7299/7945/files/PolyLite_PLA_TDS_EN_V5.4.pdf",
      "affiliateUrl": null
    },
    {
      "rank": 2,
      "note": "Prusament 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.",
      "brand": "Prusament",
      "product": "PLA",
      "material": "PLA",
      "url": "/brand/prusament/pla",
      "nozzle": "205–225 °C (401–437 °F)",
      "bed": "40–60 °C (104–140 °F)",
      "pricePerKg": null,
      "datasheetUrl": null,
      "affiliateUrl": null
    },
    {
      "rank": 3,
      "note": "PLA 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.",
      "brand": "Bambu Lab",
      "product": "PLA Basic",
      "material": "PLA",
      "url": "/brand/bambu-lab/pla-basic",
      "nozzle": "190–230 °C (374–446 °F)",
      "bed": "35–45 °C (95–113 °F)",
      "pricePerKg": null,
      "datasheetUrl": "https://cdn.shopify.com/s/files/1/0584/7236/6216/files/Bambu_PLA_Basic_Technical_Data_Sheet_bf3411ce-be39-4db7-9669-1b4671d2196b.pdf?v=1734060943",
      "affiliateUrl": null
    },
    {
      "rank": 4,
      "note": "PolyLite 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.",
      "brand": "Polymaker",
      "product": "Polylite PETG",
      "material": "PETG",
      "url": "/brand/polymaker/polylite-petg",
      "nozzle": "220–250 °C (428–482 °F)",
      "bed": "70–90 °C (158–194 °F)",
      "pricePerKg": null,
      "datasheetUrl": "https://cdn.shopify.com/s/files/1/0548/7299/7945/files/PolyLite_PETG_TDS_EN_V5.4.pdf",
      "affiliateUrl": null
    }
  ]
}