{
  "opening": "A pop at the nozzle followed by a gap is the sign the leading comment treats as water boiling in the melt. PETG bubbles can instead be a random Z seam, and three of these five threads are not about moisture.",
  "question": "Which filaments absorb moisture, and how do I tell if filament is wet?",
  "slug": "hygro",
  "useCase": "drying",
  "useCaseLabel": "Drying",
  "updated": "2026-10-20",
  "shortAnswer": "A pop at the nozzle followed by a gap is the sign the leading comment treats as water boiling in the melt. PETG bubbles can instead be a random Z seam, and three of these five threads are not about moisture.",
  "recommendedMaterials": [
    "pla",
    "petg",
    "pa6"
  ],
  "printerConsiderations": [
    "Brand-new filament can still be wet. That is a score-17 reply on r/FixMyPrint 1098exl.",
    "Popping is not always moisture. A score-12 reply on the same thread describes an air gap after a hotend rebuild that popped.",
    "r/prusa3d 1ilu19b is a CORE One waiting about 7:40 before PETG. The leading comment says an unenclosed MK4 has only the room to heat. That wait is chamber heat, not a wet spool."
  ],
  "pros": [
    "The pop-then-gap description is quoted from the highest-scored reply on the thread that recorded the pop.",
    "Drying temperatures stay on the product row and on the drying dataset."
  ],
  "cons": [
    "r/3Dprinting 11u348w and r/functionalprint 11u37q5 are the same laser-level joke. They do not diagnose wet filament.",
    "The PETG bubble thread's leading replies say the Z seam is set to random. Wet filament is the score-14 alternative, not the consensus of that thread."
  ],
  "community": "r/FixMyPrint 1098exl shows gaps that appear right after a pop, printing PLA at 200 °C (392 °F) and a 60 °C (140 °F) bed. The score-80 reply says the pop is water boiling in the nozzle and the vapor blowing a hole in the extrusion, and says to dry the spool. A score-21 reply describes the same steam gap. A score-17 reply says filament can arrive wet. A score-12 reply says popping is not always moisture and describes a hotend rebuilt at room temperature that left an air gap. r/prusa3d 1mndze5 shows bubbles in two PETG spools on a CORE One with a 0.4 mm nozzle at 235 °C (455 °F). The score-88 reply asks if the Z seam is random. The poster says it is. Two more replies treat the random seam as the cause. A score-14 reply says that, or it is wet. r/prusa3d 1ilu19b asks why a CORE One absorbs heat for about 7:40 before PETG when an MK4/S does not. The score-71 reply says an MK4 without an enclosure has only the room to heat. A score-53 reply says the gcode is waiting on a chamber temperature. r/3Dprinting 11u348w and r/functionalprint 11u37q5 are a joke about a laser-level case. The title says ABS and a flexible shell. The top comments are jokes.",
  "related": [
    "drying",
    "storage"
  ],
  "faq": [
    {
      "q": "What does wet filament sound like in these threads?",
      "a": "On r/FixMyPrint 1098exl the score-80 reply says a pop is water boiling as it hits the hot nozzle, and the vapor leaves a hole. A score-12 reply on the same thread says a pop can also be an air gap in a rebuilt hotend."
    },
    {
      "q": "Are the PETG bubbles moisture?",
      "a": "The score-88 reply on r/prusa3d 1mndze5 asks about a random Z seam, and the next replies agree after the poster checks the slicer. A score-14 reply says it might be wet instead. The post's 235 °C (455 °F) sits inside Bambu PETG HF's 230–260 °C (446–500 °F) nozzle and below SUNLU PETG's 240–260 °C (464–500 °F) nozzle."
    }
  ],
  "sources": [
    {
      "title": "SUNLU filament wiki",
      "url": "https://www.sunlu.com/wiki/61",
      "kind": "manufacturer"
    },
    {
      "title": "SUNLU PETG product page",
      "url": "https://www.sunlu.com/products/petg-3d-printing-filament",
      "kind": "manufacturer"
    },
    {
      "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": "Bambu PETG HF technical data sheet",
      "url": "https://store.bblcdn.com/ce12d65176a94f1086e6aefa238e62e2.pdf",
      "kind": "datasheet"
    },
    {
      "title": "Open Filament Database, Overture Easy Nylon",
      "url": "https://api.openfilamentdatabase.org/api/v1/brands/overture/materials/PA6/filaments/easy_nylon/index.json",
      "kind": "other"
    },
    {
      "title": "Community source, r/3Dprinting 11u348w",
      "url": "https://www.reddit.com/r/3Dprinting/comments/11u348w/",
      "kind": "reddit"
    },
    {
      "title": "Community source, r/functionalprint 11u37q5",
      "url": "https://www.reddit.com/r/functionalprint/comments/11u37q5/",
      "kind": "reddit"
    },
    {
      "title": "Community source, r/prusa3d 1ilu19b",
      "url": "https://www.reddit.com/r/prusa3d/comments/1ilu19b/",
      "kind": "reddit"
    },
    {
      "title": "Community source, r/FixMyPrint 1098exl",
      "url": "https://www.reddit.com/r/FixMyPrint/comments/1098exl/",
      "kind": "reddit"
    },
    {
      "title": "Community source, r/prusa3d 1mndze5",
      "url": "https://www.reddit.com/r/prusa3d/comments/1mndze5/",
      "kind": "reddit"
    }
  ],
  "recommendations": [
    {
      "rank": 1,
      "note": "SUNLU PLA lists 190–230 °C (374–446 °F) and a bed of 50–70 °C (122–158 °F). Drying on the row is 50–55 °C (122–131 °F) for 8 h from the SUNLU wiki. The PLA pop thread printed at 200 °C (392 °F) and a 60 °C (140 °F) bed. Both numbers sit inside this row.",
      "brand": "SUNLU",
      "product": "PLA",
      "material": "PLA",
      "url": "/brand/sunlu/pla",
      "nozzle": "190–230 °C (374–446 °F)",
      "bed": "50–70 °C (122–158 °F)",
      "pricePerKg": null,
      "datasheetUrl": null,
      "affiliateUrl": null
    },
    {
      "rank": 2,
      "note": "PolyLite PLA lists 190–230 °C (374–446 °F), a bed of 25–60 °C (77–140 °F), and drying at 55 °C (131 °F) for 6 h. 200 °C (392 °F) and 60 °C (140 °F) from r/FixMyPrint 1098exl sit on this row. 60 °C (140 °F) is the top of the bed.",
      "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": 3,
      "note": "SUNLU PETG lists 240–260 °C (464–500 °F) and a bed of 60–70 °C (140–158 °F), checked 19 October 2026, and drying at 60–65 °C (140–149 °F) for 6–8 h. The PETG bubble post is at 235 °C (455 °F), which is below this nozzle.",
      "brand": "SUNLU",
      "product": "PETG",
      "material": "PETG",
      "url": "/brand/sunlu/petg",
      "nozzle": "240–260 °C (464–500 °F)",
      "bed": "60–70 °C (140–158 °F)",
      "pricePerKg": null,
      "datasheetUrl": null,
      "affiliateUrl": null
    },
    {
      "rank": 4,
      "note": "PETG HF technical data sheet. Nozzle 230–260 °C (446–500 °F), bed 65–75 °C (149–167 °F), drying at 65 °C (149 °F) for 8 h. 235 °C (455 °F) from r/prusa3d 1mndze5 sits inside this nozzle. The leading replies on that thread blame a random Z seam, and a score-14 reply adds that it might be wet.",
      "brand": "Bambu Lab",
      "product": "PETG HF",
      "material": "PETG",
      "url": "/brand/bambu-lab/petg-hf",
      "nozzle": "230–260 °C (446–500 °F)",
      "bed": "65–75 °C (149–167 °F)",
      "pricePerKg": null,
      "datasheetUrl": "https://store.bblcdn.com/ce12d65176a94f1086e6aefa238e62e2.pdf",
      "affiliateUrl": null
    },
    {
      "rank": 5,
      "note": "Overture Easy Nylon lists 245–260 °C (473–500 °F) and a bed of 50 °C (122 °F) from the Open Filament Database. The catalog stores drying at 95 °C (203 °F) for 7 h. Nylon is the high-drying row in this set. The five threads do not print nylon.",
      "brand": "Overture",
      "product": "Easy Nylon",
      "material": "PA6",
      "url": "/brand/overture/easy-nylon",
      "nozzle": "245–260 °C (473–500 °F)",
      "bed": "50 °C (122 °F)",
      "pricePerKg": null,
      "datasheetUrl": null,
      "affiliateUrl": null
    }
  ]
}