eSun produces some transparent reusable spools which can be separated by removing two bolts. This design makes them compatible to the Masterspool conventions by RichRap. There is a generic version available that meets the original Masterspool dimensions (46.7 mm width 102 mm outer core diameter), as well as a version which is optimized for DasFilament PETG refill bundles. They commonly seem to have a larger core diameter. The adapter uses as little material as possible and also features a notch to attach the filament end.

Additional parts:

• 2x M6x35 mm screws

Printing:

• PLA / PETG or ABS if you use a dry box etc.
• arbitrary layer height
• 15%+ infill
• 3+ perimeters
• no supports

Assembly:

1. Place the M5 nuts on a flat surface and one half of the eSun spool accordingly:
2. Insert the printed adapter piece and the refill bundle. Put the filament end into the notch and take care of the alignment of the cable ties.
3. Attach the second half of the eSun spool. There is also a small notch on the outer ring. Align the filament end accordingly. Turn the pieces until the holes for the bolts are aligned properly:
4. Insert the two M6x35 mm bolts and slightly tighten them almost hand-tight:
5. Cut and remove the cable ties. Take care not to tangle the filament start by putting it through the provided holes on one half of the eSun spool:
6. Finally, tighten the bolts completely :