Measure the actual spool before choosing hardware. EIBOS lists Polyphemus clearance up to Ø250 × 170 mm with its expansion parts. Polymaker Box XL supports spools up to 3 kg and Ø300 × 118 mm; its Dock Adapter is sold separately, and Polymaker says the XL box is not designed for high-power drying.
Check actual spool clearance
Spool mass alone does not establish whether a reel will fit. Measure its outer diameter and width, then compare both with the manufacturer’s limits for the exact dryer, box, and feed path. Do not assume a 3 kg spool fits standard 1 kg equipment.
| Hardware | Published spool fit | Drying or storage | Check before use |
|---|---|---|---|
| Creality Space Pi X4 | Up to 200 mm diameter and 150 mm width | Active drying · 45–85°C | Confirm the spool fits one chamber |
| SUNLU FilaDryer S4 standard | Four 1 kg rolls; 450 × 210 × 211 mm internal dimensions | Active drying · up to 70°C in one shared chamber | Compare reel dimensions with the internal space |
| EIBOS Polyphemus | Up to Ø250 × 170 mm with expansion parts | Active drying · 30–80°C · 130 W | Expansion parts are required for the larger clearance |
| Polymaker PolyDryer Box XL | Up to 3 kg · Ø300 × 118 mm | Sealed storage; optional dock connection is not designed for high-power drying | XL Dock Adapter is sold separately |
| Polymaker PolyDryer standard box | Up to 1 kg | Sealed storage; complete system includes a 68 W dock | Standard box is not the XL version |
EIBOS Polyphemus specifications and Polymaker Box XL specifications.
Hardware for a larger spool
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Active drying · expansion option
EIBOS Polyphemus rotary dryer
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Sealed storage · up to 3 kg
Polymaker PolyDryer Box XL
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Dock included · standard box
Polymaker PolyDryer complete system
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Choose the cycle from the filament maker
There is no universal drying time based only on spool mass. Use the exact filament maker’s temperature and time, then check that the dryer can meet the setting and that the spool itself tolerates it. Do not automatically double a 1 kg schedule for a 3 kg spool.
Keep active drying separate from sealed storage. The Box XL is mainly a storage box; its optional dock adapter does not make it a high-power dryer. For product-by-product details, see PolyDryer system, 1 kg box, and Box XL. For general schedules and equipment ranges, see the filament dryer guide.
Plan the feed path
Use a stable spool support and make sure the reel turns freely before starting a long print. Route filament through the outlet or holder specified by the dryer and printer makers. If the spool is too wide or too large for the printer’s enclosed feeder, check the printer’s supported external feed path instead of forcing it into the feeder.
For two-spool rotary drying and expansion sizes, see compact dryer comparisons. For a four-spool machine, compare the Creality Space Pi X4 and SUNLU S4.
When a 3 kg spool is the wrong fit
Choose a smaller spool when the exact reel does not fit a supported dryer or feed route, or when you do not need the extra capacity. Check the dimensions of the selected spool and the limits of every part in its path.
Common questions
Will every 3 kg spool fit the EIBOS Polyphemus or PolyDryer Box XL?
No. EIBOS lists up to Ø250 × 170 mm with its expansion parts. Polymaker lists up to 3 kg and Ø300 × 118 mm for Box XL. Compare the actual spool dimensions with the selected product’s limits.
How long does it take to dry a 3 kg spool?
There is no universal time based only on spool mass. Follow the exact filament maker’s temperature and duration, and check that the dryer and spool support that cycle.
Can I feed a 3 kg spool through an enclosed filament feeder?
Do not assume it fits. Compare the actual spool dimensions with the feeder’s limits. If it exceeds them, use a printer-maker-supported external spool route and follow both manuals.